Title Studies on Diagnostic Imaging of the Caudal Vena Cava in DairyCattle( 本文(Fulltext) )

Author(s) 吉, 林台

Report No.(DoctoralDegree) 博士(獣医学) 甲第231号

Issue Date 2007-03-13

Type 博士論文

Version publisher

URL http://hdl.handle.net/20.500.12099/21414

※この資料の著作権は、各資料の著者・学協会・出版社等に帰属します。

Studies on Diagnostic Imaglng Ofthe Caudal Vena Cava in Dairy Cattle●

(乳牛の後大静脈における画像診断に関する研究)

2006

The United Graduate School of Veterinary Sciences Gifu Umiversity

(Obihiro University of Agriculture and Veterinary Medicine)

Jilintai

Table of Contents

Page

Chapterl･ ･･ ･

･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･1

Introduction･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･1

Chapter2･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･4

RadiographicParametersoftheCaudalVenaCavainDairyCattle ･ ･ ･ ･ ･ ･

4

Introduction･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･4

MaterialsandMethods･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･

･5

Results･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･6

Discussion ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ I

･8

Chapter3 ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･23

Pulsation of the Caudal Vena Cava Alters Parturition and Lactation in Dairy

Cattle･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･23

Introduction ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･

･23

MaterialsandMethods ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･

･24

Results ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･26

Discussion･ ･･ ･

･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･

･28

Chapter4･･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･

･36

Dimensions and Dynamics of the Caudal Vena Cava and Hepatic Vein Alter

1

ParturitionandLactationinDairyCattle･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･36

Introduction ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･36

MaterialsandMethods ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･

･37

Results ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･

･39

Discussion ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･

･41

Chapters ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･

･51

Intravascular Pressure of the Caudal Vena Cava Alters Reproductive Cycle of

I)airyCattle ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･

･51

Introduction ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･

･51

MaterialsandMethods ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･52

Results ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･

･54

Discussion･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･

･55

Chapter6 ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･

･71

The Clinical Application of FIuoroscopIC and Ultrasonographic Measurementof

theCaudalVenaCavainDairyCattle ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･71

Introduction ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･

･71

MaterialsandMetbods ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･

･72

Results ･ ･ ･ ･ ･ ･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･

･73

Discussion･ ･ ･ ･ ･･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･･ ･ ･

･75

ii

Chapter7･ ･ . ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ . ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･86

GeneralI)iscussionandConclusion ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･86

JapaneseSummary ･ ･ ･･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･92

Acknowledgements･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･

･98

References･･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･ ･

･99

iii

Abbreviations :

Ao, diameter of the aorta;

ACVP, intravascular pressure of abdominal caudal vena cava;

BW, body weight;

Chq chest girth;

CI, collapsibility index;

CVC, caudal vena cava;

CVCare, average area of the caudal vena cava;

CVCave, average diameter of the caudal vena cava;

CVCdeptb, depth oftbe caudal vena cava;

CVCmax, maximum diameter oftbe caudal vena cava;

CVCmin, minimal diameter of the caudal vena cava;

CVCp, pulsation beat of caudal vena cava;

CVCp.i., pulsation index of caudal vena cava;

CVP, central venous pressure;

ECG electrocardiogram;

HCAJ, the Holstein cattle association of Japan;

HV hepatic veln;

HW, height at withers;

IVC, inferior vena cava;

JVP; jugularvein pressure;

RAP, right atrial pressure;

RVP, right ventricular pressure;

1V

TCVP, intravascular pressure of thoracic caudal vena cava;

vL, length of the 8th thoracic vertebrae;

Wq weeks gestation;

WPP, week postpartum.

Ⅴ

Chapter 1

Introduction

As industrial animals, adult dairy cows essentially undergo a continuous cycle of

reproductive actlVlty. Throughout their entire lives they are either pregnant or lactatlng,

and approximately half of this time they are subjectedto both conditions simultaneously.

At the same time there are severe changes in abdominal pressure and the cardiovascular

system, especially the circulatory system, which play an important role in maintainlng

the high lactating capaclty. However, circulatory dysfunction is not only a common

disease, but also a main reason fわr a decline in milk secretion in dairy cows.

Considering the economic efrlCiency of dairy cows, early diagnosis of circulatory

dysfunction is crucial. There are many methods used to diagnosis cardiac disease,

including an echocardiographic examination fわr severe cardiac disease, however, an

echocardiographic test requlreS a Skilled professional operator. What is needed isan

efrlCient and simple diagnostic method that canbe used in a clinical practice.

In human medicine and small animal clinics, measurlng the dimensions and dynamics

of the vena cava is widely used as an effective method for the diagnosis of circulatory

dysfunctions, because it is a highly compliant low-pressure capacity vessel (30). The

intravascular pressure of vena cava is referred to as central venous pressure (CVP),

which clearly renects the right atrial pressure an indicatorof a healthy

subjector the

presence of cardiac illness (10, 15, 84 and 98). CVP may be in且uenced by abdominal

pressure, blood volume, cardiac output, venous constriction or arterial dilation (44).

Consequently, the measurement of a CVP can be help丘11 in the diagnosis and

management of a variety of critical illnesses and injuries including trauma, burns, sepsis,

1

congestive heart failure, cardiogenic shock, traumatic brain injuryin humans (22, 28, 36,

75, 86, 87 and 93)･Similarly, the dimensions and dynamics of the inferior vena cava

(ⅠVC) vary with changes in circulatory blood volume and total body water (40, 45 and

55), which may be in且uenced by the systemic and hepatic circulatory status (13), the

compliance of the hepatic parenchyma (97) and changes in thoracic and abdominal

pressure (65)･ Therefわre, measuring the dimensions and dynamics of the IVC is widely

used as a noninvasive method, instead of uslng Catheterization to measure CVP, of

diagnosing Circulatory dysfunction in humansand small animals.

In human medicine, the IVC corresponds to the caudal vena cava (CVC) of cows, and

both the diameter and collapsibility index (CI,called the pulsation index incattle)of the

IVC are important for the diagnosis of circulation dysfunction. Measurement of the IVC

has been reported as a means of diagnoslng patients with cardiac disease classically

associated with right-sided congestive heart failure, including severe or chronic

congestive heart failure (27, 34), tricuspid incompetence (71, 96), and pericardial

e凪ISion (20, 71)･ Furtbe-ore, the dilatation of the IVC is also observed in patients

with cirrhotic portal hypertension (97)･Measurement of the IVC has been applied to

assess right heart function (57),the risk of pregnancy-induced hypertension (79),and to

monitor the effect of therapy on patients with congestive heart failure (56).

In small animal clinics, dilatation of the CVC is o氏en listed as an indicatorof

right-sided congestive heart failure (26, 47)and isapplied to the diagnosis of dogs with

that type of condition, including heartwormdisease (51), pericardial disease (26),

pulmonic stenosis (78),tricuspid valve regurgitation and dilated cardiomyopathy (47).

In dairy cows, however, with the exception of Braun U. et al. (13, 14), no one has

described the alteration of the CVC secondary to poISOnlng Or thrombosis of the CVC.

2

A洗er treatlng dairy cows in a clinical practice for several years, I noticed alterations of

the CVC in different reproductive stages when uslngfluoroscopIC Or ultrasonographic

teclmiques for diagnosis. Therefore, I referred to the human medicine and small animal

clinics to check our hypothesis that focuslng On the CVC may offer a useful means of

the diagnoslng Circulatory dysfunctions･ Consequently, the objectivesof this study were:

1) To clarify the alteration of hemodynamics and dimensions of the CVC and hepatic

vein (HV) in dairy cows during different stages of single reproductive cycle; 2) To

clarify the changes in intravascularpressure of the CVC and the right cardiac pressure

of dairy cows during different stages of single reproductive cycle; 3) To investigate

whether the dimensionsand dynamics of the CVC and the HV renect the CVP or right

cardiac pressure; 4) To demonstratewhether thefluoroscopic and ultrasonographic tests

are useful methods for the diagnosis of circulatory dysfunctions･

3

Chapter 2

Radiographic Parameters of the Caudal Vena Cava in Dairy Cattle

Introduction

Tbe vena cava is a highly compliant low-pressure capacity vessel (30).Its dimensions

and dynamicsvary with changes in total body water and circulatory blood volume (45,

55), and may be influenced by the systemic and hepatic circulatory status (13), the

compliance of the hepatic parenchyma (97) and changes in thoracic and abdominal

pressure (65).

In human medicine, the inferior vena cava (IVC) corresponds to the caudal vena cava

(CVC) of cows, its diameter and collapsibility index (CI) are both important for the

diagnosis of circulation dysfunction･ The measurement of IVC has beenreported in

patients with cardiac disease classically associated with right-sided congestive heart

failure including severe or chronic congestive heart failure (27, 34), tricuspid

incompetence (6,96) and pericardial effusion (6,20).Furthermore, the dilatation of the

IVC is also obseⅣed in patients with cirrhotic portal hypertension (97).The

measurement of IVC has been applied to assess right-heart function (57),the risk of

pregnancy-induced hypertension (78),and to monitor the effect of therapy in patients

with congestive heart failure (27).

In smallanimal clinics, dilatation of the CVC is often listed as an indicat.r.f

right-sided congestive heart failure (26, 47) and is applied to the diagnosis of dogs with

that condition, including heartworm disease (51), pericardial disease (26), pulmonic

stenosis (88), tricuspid valve regurgitation and dilated cardiomyopathy (47). The

4

dimensions and dynamics of the CVC in cattle have not been documented

systematically･ The aim of this study is to evaluate the radiographic parameters of the

CVC in healthy dairy cows.

Materials and Methods

Cows･･ Eighty-one healthy Holstein cows were divided into 2 groups according to the

"Standard Growth Values of Holstein Dairy Cattle" (91). Group 1 comprised 43

growing cows ranging in age丘om 9 to 35 months (mean土SD: 18.72士8.16months).

Among the 43 growlng COWS, 16 were examined in the lactatlngperiod of their丘rst

calve･ Gro叩2 consisted of38 mature cows over 36 months of age (37 to 95, mean士SD:

60･87土15･84months)･

During the study, all proceedings were perf♭med in accordance

with the guidelines approved by the Animal Research Ethics Committee of Obihiro

Universlty OfAgriculture and Veterinary Medicine ･

X-ray αamination･･ The radiographic examinations were performed uslng an

industrialfluoroscopicapparatus (MG321; Hitachi Medico, Tokyo) with a camera

installed in a large animal X-ray mass scannlng Car･ Each cow was loaded into the X-ray

car, and was restrained in the middle of the stock･ While perfbmlng the tests listed

below, the radiographic images were recorded on videotape･ The initial diagnosis of the

animals'health was perfb-ed by X-ray ln a Standing position･ These included: the

contractions of the reticulum and the presence of fbrelgn bodies, level of omasum gas,

the position of the abomasums, the content and level of rumen gas, level of colon gas,

imaglng Of the lungs, the CVCand the surface of the diaphragm･ Continual observation

was done of the CVC, thoracic vertebrae at the same intercostal spaces as the CVC

5

observation (usually the 8th thoracic vertebrae, Fig. 1),and the aorta positioned below

the same thoracic vertebrae. A timer was set when the video was recording the pulsation

of the CVC, while simultaneously doing electrocardiography (ECG). Later, the

videotape was replayed to measure the length of the 8th thoracic vertebrae (VL) (Fig.2),

diameter of the aorta (Ao) (Fig. 2), maximal and minimal diameters of the CVC

(CVCmax and CVCmin) at the end of the inspiration (Fig.3 and 4).

Statistical Ana[ysis･'The average diameter of CVC (CVCave) was defined as:

CVCave = (CVCmax + CVCmin)/2; Pulsation index of CVC (CVCp.i) was de丘ned as:

CVCp.i. - (CVCmax-CVCmin)/CVCmaxx 100

Characteristics of cows, diameter and pulsation of CVC were expressed as mean土SD

value for each group･ Linearregression analyses and independent-sample t-tests were

performed to analyze all related data using the SPSS analysis software (SPSS 12.0.J for

Windows Advanced Models, SPSS Inc., Japan). p values of less then 0.05 were

considered statistically slgni丘cant.

Results

As shown in Table 1, growing cows were significantly youngerand weighed (BW)

significantly less than mature cowsわ<0.001).The height at withers (HW) and chest

girth (ChG) of growing cows were significantly @<0.001 both) lower than that of

mature cows, respectively･ Furthermore, the diameter of the aorta and the length of the

8th thoracic vertebrae in growing cows were significantly (p<0.001 both) lower than in

milking cows, respectively･ The maximum diameter of the CVC was slgniflCantly lower

in growing cows than in mature cows @<0.01) (Table. 2). On the other hand, the

6

minimum diameter of the CVC fわr all cows was 18.83土4.08mm, and values did not

differ significantly between the two groups of cattle･ However, the average diameter and

the pulsation indices of the CVC were slgnificantly lower in growlng COWS than in

mature cows @<0.01).

Linear regression analyses used to evaluate the correlation between the diameter of

the CVC and the characteristics of all cattle revealed significant coefficients･ Value of

R2 fわrlinear regression analyses of age, BW, HW, Chq Ao and VL was 0.22, 0.33, 0.26,

0･24, 0･29 and O･36, respectively (Fig.5-10). Linear regression analyses of correlation

between the diameter of the CVC and all the characteristics of growlng COWS Showed

slgnificant coefrlCients･ Values of R2 for linearregression analyses of age, BW, HW,

Chq Ao and VL were O･23, 0･26, 0･17, 0･14, 0･18 and 0.35, respectively. But in milking

cows, the diameter of the CVC was merely slgniflCant correlated to the characteristics

of BW, HW, Ao and VL; their R2 values fわr linear regression analyses were O･23, 0.10,

0･21 and O･17, respectively･ Linear regression analyses also showed that there was no

correlation between pulsation indexes of the CVC and the various characteristics of the

cattle in both groups.

Tbe ratio of the CVCave to the diameter of the aorta (CVCave/Ao) was 0.62土0.09

(ranged from O･39 to O･90) in growing cowsand O･60士0.10 (rangedfrom 0.43 to 0.79) in

mature cows･ Ratio of the CVCave to the length of the 8th lhoracic vertebra

(CVCaveⅣL) was O･42士0･06 (ranged丘om O･25 to 0.59) in growing cows and

O･41i=0･06 (ranged from O･25 to 0. 52) in mature cows (Table 2). Furthermore, the ratio

for the diameter of the aorta to the length of the 8th lhoracic vertebra (AoNL) was

O･69士0･08 (ranged from O･55 to O･90) in growing cows and 0.67土0.05 (ranged from 0.57

to O･80) in mature cows, respectively (Table 2). Thus, the ratio of the CVC to Ao and

7

VL or the ratio or Ao/VL was essentially consistent in both groups, and its mean values

were O･61士0･10, 0･41士0･06and O･68士0･07 in all cows, respectively (Table 2).

Discussion

An examination of the growth pattems of Holstein cows revealed a cuⅣepattem fわr

BW, HW and ChG with age from birth to 60 months of age･ Such Holstein cows reach

95% of their mature weight at叩prOXimately 36 months of age (91). In the present study,

mature Holstein cows over 36 months of age were considered to be almost at their

mature weight, BW, HW, ChG; Aoand VL values were related to gro融h; so, growing

cows had significantly lower BW, HW, Ch(主Ao and VL values than mature cows.

Although there was no statistically slgnificant difference in minimum diameter

between growing COWS and mature cows, the minimumdiameter of mature cows

appeared to be higher than that of growing COWS･ However, the maximumand average

diameter of the CVC, were slgnificantly different between growlng COWS and mature

cows･ The CVCp･i･ was also slgni丘cantly higher in growlng than in mature cows. These

differences were considered to be, not only the effect of growth, but also of circulation

status･ In mature cows, milk precursors come丘om the blood･ On average, 400-500

units of blood are needed fわreach unit of milk synthesized by a high producing dairy

cow (35, 49)･ In human medicine, Duvekot J･J･ et al･ (24) perf♭med volume-loading

examinations in healthysubjects

to evaluate the ultrasonographic alteration of the

inferior vena caval diameter and showed that the minimal and maximal diametersof

IVC were both increased a鮎r volume loading･

Individual differentiation between cows prohibits a comparison of absolute CVC size,

8

but the ratio of CVC size to other anatomic structures may provide a useful way to

objectivelyassess CVC size･ Lehmkuhl L･B･ et al. (47) performed quantitative analysis

of CVC size in healthy dogs and ones that had suffered congestive heart failure to

con丘m that radiograpbic evaluation of CVC size, as a ratio to the diameter of the aorta,

length of the thoracic vertebrae or width of the 4th rib, may provide a diagnostic clue

that right sided heart abnomalities are present･ However, in cows, such studies have not

been done yet･ The present study employed Lehmkuhl-s (47) method to compare the

ratio of the CVCave to the Ao and the VL in healthy growlng and mature cows.

However, the measurement of rib width in cows was discarded for its low

reproducibility due to its movement by resplration･ In addition, the other characteristics

such as body weight or heart girth were altered inpregnancy･ Consequently, for

comparison, the diameter of the aortaand the length of the 8th fhoracic vertebrae were

measured by the X-ray as well as with the diameter of the CVC. Therefわre, the error

values were within the minimum limitation in the ratio of the CVCave to the Aoand VL,

respectively･ The results also showed tha土the ratio of the CVCave to the Ao and the VL,

the ratios of Ao to VL were consistent between growlng COWS and mature cows, while

the CVCave was slgnificantly correlated with Ao and VL in both growlng COWS and

mature cows.

As a high compliant low-pressurecapaclty Vessel, changes in IVC diameter have

been used to evaluate numerous circulation statuses in human medicine. Vaturi.M. et al.

(96) reported that the dilatation of the inferior vena cava occurs in severe tricuspid

regurgitation associated with right-sided congestive heart failure･ Ando Y. et al. (4)

demonstrated IVC diameter decreased proportionally to theamount of ultrafiltration in

patients undergolng hemodialysIS, a Warnlng indicator of a high level of body fluid

9

retention･ Moreover, Hollerbach S･ et al･ (34) con丘med that ultrasonographic

measurements of IVC diameter and insplratOry movements are a quantifiable and a

reliable approach to assess the hypeⅣolemia associated with chronic congestive heart

failure･ Natori H. et al. (65) verifled that the diameter of the IVC and the amount of

insplratOry COllapse inpatients lying ln SuPlne, 1e氏or right lateral position correlated

with the CVP･ Furthe-ore, diameter of the IVC also has been applied to evaluate the

risk of pregnancy-induced hypertension and fetal compromise (78, 79). Lyon M. et al.

(55) discovered in study using blood donors that the measurement of the IVC diameter

is a reliable indicator ofblood loss, even when a small amount ofblood is donated; the

diameter of IVC decreases slgniflCantly･

In conclusion, the diameterof the CVC correlates to the growth of cows･ Furthermore,

the ratios of CVCave to the diameterof the aorta and length

of the 8th lhoracic vertebra

were a fixed value in both growlng and mature cows even if the parameters slgnificantly

differ in both groups･ However, as an industrial animal, mature dairy cows essentially

repeat reproductive stages continuously･ Throughout their entire lives they are either

pregnant or lactating, and approximately half of this time they are subject to both

conditions simultaneously･ Therefわre, additional studies are needed to examine the

alteration of intravascularpressure and the dimensions

and dynamicsof the CVC of

cattle during the reproductive cycle, including deliveryand different lactatlngStageS･

10

Fig. 1. Be measured position of the caudalvena cava (CVC), which is near to the diaphragmandwithinthe 7th

and8thribs.

Fig･ 2. Showingthe measured position of the VLand Ao, VL: length of the 8ththoracic vertebrae, Ao: diameter of aorta

Fig. 3. Showing the CVCmax in the end of inspiration, CVCmax: maximumdiameter of the caudalvena cava.

Fig･ 4･ Showingthe CVCmin in the end of inspiration; CVCmin: minimumdiameter of the thoracic CVC

Table l･ Mean土SD values for age, BW, HW, Chq Ao, VL for the two groups of cows

Growing cows (n-43

18.72土8.16

419土122

131土8

174士18

36.15土4.13

52.73土4.46

Adult cows (n-3革

60.87土15.84

648土53

145土4

206土6

40.92土4.96

60.86土5.27

All (n-8n

38.49土24.47

538土147

138土10

191士21

38.39土5.10

56.55±6.32

P*

1.44E-20

9.4E-15

2.8E-13

2.5E-13

1.34E-05

1.58E-10

Age (Mo)

BW (kg)

HW (cm)

CbG (cm)

Ao (mm)

VL (mm)

*Value ofp is showlng the difference in each characteristic of growlngand adult cows･ BW- body weight･

HW- height at withers･ ChG- chest girth･ Ao- diameter of aorta･ VL- length of 8th vertebrae thoracic;

Mo: month; E-a-x 10-a

Table 2･ Mean土SD values for CVCmax, CVCmin, CVCave, CVCp･i･, CVCave/Ao, CVCaveNL AONL for the two

groups of cows

Growing cows (n-431 Adult cows (n-381 All (n-81

CVCmax (mm)

CVCmin (mm)

CVCave (mm)

CVCp.i.

CVCave/Ao

CVCave/VL

Ao/VL

25.10士4.70

17.98土4.ll

21.60士4.25

28.28土7.57

0.6土0.10

0.41土0.06

0.69土0.08

30.34土5.38

19.62土3.93

25.27土3.99

34.42士13.43

0.62土0.09

0.42士0.06

0.67土0.05

27.82士5.69

18.83土4.08

23.32士4.41

31.16土11.09

0.61土0.10

0.41土0.06

0.68土0.07

*Value of P is showlng the differentiation of CVCmax, CVCmin, CVCave, CVCp･i･, CVCave/Ao, CVCaveNLand

AoⅣL of growlng COWS and adult cows; CVCmax- Maximum diameter of caudal vena cava; CVCmin- Minimum

diameter of caudal vena cava; CVCave- Average diameter of caudal vena cava; CVCp･i･-

Pulsation index of caudal

vena cava; cvcave/Ao -Ratio of caudal vena cava to aorta; CVCaveNL -Ratio of caudal vena cava to 8th lhoracic

vertebra; AoNL -Ratio of aorta to 8th fhoracic vertebra.

CVCave -20.03+ 0.09 * Age

20.0 40.0 60.0 80.0

Age (mond1)

Fig･5･ Scatterplot showlng relation of average diameter of the caudal vena cava to the age

Graph is depicting linear regression analyses between diameters of caudal vena cavaand age of cows･ Equation for

line is as follows: CVCave - 20･03+ 0･09xMonth, r2-0･22, n-81, p<0･01･ CVCave: average diameter of the CVC,

Mo山b: month of age.

CVCal確-14.01 +0.02*8W

300.0 400.0 500,0

BW (Kg)

｢_｣600.0 700.0

′ー

喜ヽ■′

巨t:>CQ

UiU

Fig･6･ Scatterplot showlng relation of average diameter of caudal vena cava to body weight

Gr叩h is depicting linear regression analyses between diameters of caudal vena cava and body weight of cows.

Equation for line is as follows: CVCave - 14･01 + 0･02xBW; r2 - 0･33, n-81, p<0･01･ CVCave: average diameter of the

CVC; BW: body weight.

CVCave =-957 +0.24* HW

｢

∃∃】

～

l

120.0 130.0 140.0

ⅡW (mm)

150.0

′■ヽ

喜= 25.0

>Cg

UiU 20.0

Fig･7･ Scatterplot showlng the relation of average diameter of the caudal vena cava to the height at withers

Graph is depicting linear regressionanalyses between diameters of caudal vena cavaand height at withers of

cows･ Equation for line is as follows: CVCave- - 9･57+ 0･24xHeight,R2 - 0.26, n-81, p<0.01. CVCave: average

diameter oftbe CVC; HW: height at withers.

CVCave -313+0.ll* ChG

メ-ヽ

≡≡

Y 25,0

>d

U

5 20.0

葛5;iii

●

.･ ･･:'･･:'/･

● ●●

● ●●

｡ ● ; ●

150.0 175.0 200.0

ChG (cm)

Fig･8･ Scatterplot showlng relation of average diameter of caudal vena cava to chest girth

Graph is depicting linear regressionanalyses between diameters of caudal vena cava and heart girth of cattle･Equation for

each line is as follows: CVCave - 3.23+ 0.11×Chq R2 - 0･24, n-81,p<0･01･CVCave: average diameter of the CVC; ChG:

chest girth.

CVCave -5.56+ 0.46 * Ao

jiiiid

35.0 ･｣

1 5.0

′-ヽ

皇ヽ一′

○

>

a>･U

I

｣

レ1.

･i

lt

1｣】

/,･

L∴/t

-

J ●

●

:●

･

∴ ･

●･

30.0 35.0 40.0

A¢ (mm)

ユ=II

45.0

Fig･9･ Scatterplot showlng relation of average diameter of caudal vena cava to the diameter of aorta

Graph is depicting linear regressionanalyses between diameters of caudal vena cava and the diameter of aorta in cows･

Equation for line is as follows: CVCave - 5･56+0･46xAo, R2 - 0･29, n-81, p<0･01･ CVCave: average diameter of the CVC,

Ao: diameter of aorta.

CVCave -Jll +0.42* VL

1

】

35.0･1

30.01′~ヽ

喜25･01】

u

20･01

ニ≡･〇-●●●l

●

50.0

●

/-/

】ーー■~｢

●

巴岳5

.･:･･:･･･:･.'･''･'.I

･

･

一] l-i

60.0 70.0

VL (mm)

Fig･ 10･ Scatterplot was showlng relation of average diameter of caudal vena cava to length of 8th thoracic vertebra･

Gr叩h is depicting linea=egression analyses between diameters of caudal vena cava and the length of 8th thoracic

vertebra in cows･ Equation for line is as follows: CVCave- - 0･21+0･42xVL, R2- 0･36, n=81, p<0･01･CVCave: average

diameter of the CVC; VL: length of the 8th thoracic vertebrae･

Chapters

Pulsation of the Thoracic Caudal Vena Cava Alters Parturition and Lactation in

Dairy Cattle

IntrodⅦction

As industrial animals, mature dairy cows essentially undergo continuous cycle of

reproductive activity･ Througho山tbeir entire lives they are either pregnant or lactatlng,

and approximately half of this time they are subjecttoboth conditions simultaneously.

However, there are dramatic anatomical and bemodynamic alterations occurrlng in dairy

cows'body during the pregnancy, delivery and lactation of reproductive cycle.

In humans, as the uterus enlarges, except fわr the displacement of the abdominal

viscera, the diaphragm is elevated, and the rib cage is displaced upward and widens, as

well as increasing the lower thoracic diameter and the thoracic circumference

simultaneously with an increase of intrathoracic pressure (63). Similarly, the assessment

of change in abomasal position during the last three months of gestation and first three

months of lactation renect the displacement of the abdominal viscera for pregnancy ln

dairy cows (95,99).

It is wellknown that a normal pregnancy lS Characterized by arterial and venous

vasodilation and by increased intravascular volume in humansand cows. The increases

in bloodvolume progress until ten by as much as 45-50%. Cardiac output increases

approximately 40% during pregnancy. Stroke volume and heart rate increase over the

course of the pregnancy･ The obstruction caused by the uterus on the inferior vena cava

and the pressure of fetal presentlng On the common iliac vein can result in decreased

23

blood retum to the heart (41, 63 and 92). Therefore, measurement of the inferior vena

cava diameter is applied to predict the risk of pregnancy induced hypertension and fetal

compromise in humans (78, 81).

A氏er delivery, however, the abdominal viscera and diaphragm are loosened by

retraction of the deflated uterus･ The hemodynamic changes are most striking during

labor and immediately postpartum･ Most of the haemodynamic alterations that occurred

during pregnancy returnto baseline within 6-8 weeks after delivery･ However, this

appears to be variable (68, 72). Blood volumeand total body water decreased from

blood loss during delivery and postpartumdiuresis･ Postpartum diuresis peaks between

the 2nd and 5th day a鮎r delivery (68), simultaneously cardiac output decreased

strikingly (approximately 28%) by 2 weeks aRer delivery (76). During the lactating

period, the hemodynamic and cardiac functions were altered, especially the circulatory

system, which play an important role in maintaining high lactating capacity (32, 73).

In chapter 2, I demonstrated that the parameters of the thoracic CVC may provide a

useful message for the diagnosis of the heart disease in dairy cows･ Furthermore, I

found that there were some variances in the thoracic CVC in different reproductive

stages of dairy cows･ In view of these findings, the aim of the current study was to

clarify whether the dimensionsand dynamics of the thoracic CVC reflect the anatomic

and hemodynamic alterations of dairy cows in reproductive stages including, pregnancy,

delivery and lactation.

Materials and Methods

AnL'malsI Prior to the experiment, 22 pregnant Holstein cows between 21 to 84

24

months of age were subjectedto serologlCal and radiologlCal examinations to exclude

any with circulation dysfunctions or other diseases･ The X-ray scannlng Was done

longitudinally on each cow from the first dry period (35th week post gestation)

throughout the lactatlng period oftbe 4也, loth, 15也, 25th, 35th, and 40th week postpa血m

(WPP)･ However, seven out of 22 cows were rejecteddue to their low lactation or low

reproductive capabilities after the 35th wpp･ The remalnlng COWS Were teSted 40th wpp.

Five cows were nonpregnant or miscarried, four cows were in their lst trimester (2-6

weeks gestation (WG)) while six cows were in their 2nd fo 3rd trimester (20-36 WG).

X-ray scannLng eXamination= The X-ray scanning examinations were performed

with an industrial nuoroscope (MG321 ; Hitachi Medico, Tokyo) with a camera loaded

in a large animal X-ray mass scannlng Car･ A洗er each cow was placed in the car, and

restrained in a standing position in the middle of the stock, radiographic images were

taken from the right side of the standing cow, and Lehmkuhl's (47) method was

employed to measure the fわllowing: 1) CVCmax and CVCmin at the end of expiration

and 2) VL and 3)Ao fわra comparison of body structures considered not to be directly

affected by the alteration of the CVC, but positioned in the same intercostal spaces as

the location of the CVC measurements･ From these measurements, the CVCave and

CVCp･i･, the ratio of CVCave/Ao, CVCave/VL, and Ao/VL were then calculated same

as chapter 2.

ElectrDCardiogram= An electrocardiogram of each cow was taken in rhytlmwith the

per minute pulsation oftbe CVC.

Statistical ana[ysis･･ Statistical analyses were done by corre-procedure and mixed

model procedure (The SAS System for Windows, v･ 8･2; SAS Institute Inc, Japan) for

repeated measurement with the followlng formula:

25

Yces-p+ Cc+ Ee + Ss +Pm+cecs

C-cow(ト22)

E-Experiment number (1-7)

S-Season (1,2, 3, 4)

P-Pregnant trimester (0,1, 2, 3)

Eecs-random residual effect

A mixed model in SAS was used fわr analysts Of variance of diameter and the CVC

pulsation index･ After significant F -tests (P<0.05), least squares means were

compared in Scheffe's i-tests, the difference was considered statistically slgniflCant

when p < 0･05･ Experiment number, season and gestation trimester were treated as a

fixed effect, and individual cows as a random effect.

Resu一ts

In the present study, the experiment was conducted丘om the dry period of each cow

to the end of the lactating period･ The study lasted two years, through all of =okkaido's

four seasons･ The clear changes in seasonal temperatures in Hokkaido are considered as

a fixed effect for the mixed model to demonstrate that the seasons can be ignored as a

fixed effect in the present study･

As shown in Fig･ 1 1, the linear regression analyses revealed that per minute pulsation

of the CVC and per minute heartbeat were essentially consistent statistically (R2-0.99,

n-22, p<0.001).

26

The CVCave was 27･7土3･95mm (mean土SD) in the dry period, and then there was an

increasing tendency in the 4th wpp (29.32±5.74mm), but no difference was detected.

The CVCave were 27･47土4.53, 28.56士5.58, 30.10土5.66, 30.24土5.ll and

30･59土5･05mm in the loth, 15th, 25th, 35th, and 40th wpp, respectively, and there were no

differences detected within all of the values (Table 3, Fig. 12).

Tbe CVCp･i･ was 42･13土10･97 during the dry period, and decreased to 33.73±14.23

in the 4th wpp with signiflCant Values Q)<0.01).Thereafter, there was an increase in

cvcp･i･ (38･55士12･72)in the loth wpp, which peaked in the 15th wpp (41.9士10.37).

There was a significant difference detected between the values in the 4th and 15th wpp.

However, CVCp･i･ values decreased to 34･79士14･98 in the 25tb wpp, and then increased

again and throughout the test period (43.47土11.23 and 43.45士10.80) in the 35tb and 40也

WPP, respectively･ The CVCp･i･ values in the 4th and 25th were slgni丘cantly lower than

that in the 35thand 40thwpp (a11p<0･05)(Table 3, Fig. 12).

The average daily milk yield per month was 41･08土7･21K･g in the 4th wpp, and then

reached a peak value of 43･56士6･48Kg ln the loth wpp･ There was a decreaslng

tendency ln the average daily milk yield per month till the end of the experiment.

Corre-procedure was used to evaluate the correlations between all the parameters and

milk yield･ However, there was no correlation detected between the milk yield and the

average diameter and pulsation of CVC.

Furthemore, the ratio of the CVCave to the VL (CVCaveⅣL) and the Ao

(CVCave/Ao) showed some fluctuation, but no differences were detected within related

values (Table 3, Fig. 13).

27

Discussion

The statisticalanalysis demonstrated that per minute pulsation of CVC signiflCantly

coincided with the per minute heartbeat･ This result contradicts a previous study, which

reported that the coll叩Sibility of IVC was regarded to be a resplratOry event in humans

(7)･It may be possible to ascribe the difference to the measuring posture in humans and

dairy cattle･ Our且uoroscoplC measurement Of the thoracic CVC of dairy cattle was

performed in a standing position; in this position, due to gravlty the CVC was free from

the pressure of a large abdominal mass･ However, ultrasonographic measurement of the

inferior vena cava in the infrahepatic reg10n Was Performed in humans with a suplne Or

le氏1ateral position, which exerts pressure on the structures within the abdomen and

thorax (58).

In humans, the diameter of the IVC is altered during the resplratOry phase-reaching

a minimum diameter at the end of insplration, and then distending during explration

(90)･The collapsibility index of the IVC is correlated with the CVP (90).Furthermore,

the dimensions and collapsibility index of the IVC has been demonstrated to be

influenced by total body nuid (4, 40), circulation blood volume (24, 55) and

intrathoracic and intraabdominal pressure (78,90).In the present study, I demonstrated

that the pulsation rhytlmofthe CVC in cows was heartbeat related, not respiratory･ The

pulsation of the thoracic CVC was visible under the bronchus, between the shadows of

the right atrium and diaphragm, with the diaphragmmovlng along the craniaト℃audal

axis by resplration･ The pulsation range of the CVC appeared in different individuals.

However, the dilation of the CVC in all cows resulted丘om the right atrial systole and

transmitted rapidly toward the diaphragm･ The systole of the CVC also orlglnated from

28

the right atrial diastole and transmitted r叩idly toward the diaphragm･ Consequently, the

pulsation of the CVC was repeated rh叫bmically by the right atrial systole and diastole.

Furthermore, statistical analysュs Showed that per minute pulsations of the CVC were

equal to the per minute heartbeat･ The data indicate that at the end of the systole of right

atrium, minimal blood flows from the CVC to the right atrium and there is a subsequent

increase in the widest diameter of the CVC･ In the end of the diastole of the right atrium,

however, maximal bloodflows from the CVC to the right atrium and the VCV reaches

its narrowest diameter.

StatisticalanalysIS uSlng Scheffe's t-test indicated that there was a slgnificant change

in the CVC pulsation index in pre-and postpartum and lactatlng Periods with a high

CVC pulsation index in the dry period, 15th, 35也and 40th as well as a lowpulsation

index in the 4th and 25th wpll respectively･ Such shi允s may be due to some

physiological changes such as, pregnancy or lactating or both in the cows. In other

words, I observed high CVC pulsation index values in pregnancy, at the lactationpeak,

and even in low lactating periods with early pregnancy･ On the contrary, there were low

CVC pulsation indexvalues Just a鮎r delivery and low lactation

with non-pregnancy･

The drastic changes in the CVCp･i･ in dairy cows were probably due to the tboracic

CVC wall, which experiences two kinds of alterative pressure during pregnancy,

delivery and the lactating period･ One is the intravascular filling pressure by the

elevated venous retum; and the other one is the intratboracic pressure which is

correspondingly altered by the changes in abdominal pressure･

It is well accepted that a normal pregnancy lS Characterized by a large increase in

total blood volume and in cardiac output (85, 94)･ Blood volume expansion appears

early during the pregnancy and continuously lnCreaSeS tO 50% of the basicvolume.

29

Simultaneously, cardiac output increases to 40-50% higher than the nonpregnant values･

As the cardiovascular system is essentially a closed loop, the increased cardiac output

must lead to increased venous retum･ However, from mid-pregnancy, the enlarged

uterus compresses the vena cava obstmcting venous retum and thereby causlng

increased cardiac preload and intravascular pressure･ On the other hand, the enlarged

utems compresses the abdominal viscera causlng Cranial movement of the diaphragm to

increase intrathoracic pressure (16). However, the increased intrathoracic pressure

opposes the filling pressure of the thoracic CVC promotlng Its COnStriction･ After

delivery, the intrathoracic pressure is decreased by retraction of the deflated uterus, and

the loss of extra pressure on the outer wall of the thoracic.

During the lactatlng Period, the cardiovascular system plays an important role for

maintainlng bigb milk yield･ As the plasma and total blood volume increaseand thereby

causes increased cardiac output, the intake of food and water is increased in lactatlng

dairy cows･ As theamount of feed intake has a highly slgnificant linear effect on milk

yield and the quantlty Of water consumed is closely related to the amount of water

secreted in the milk (66, 100)･ Furthermore, the decreased plasma osmotic pressure

promotes the circulatory blood to rehydra土e and thereby causlng lnCreaSed total blood

volume in the lactating period (89)･Such an alteration of circulatory blood volume and

cardiac output leads the changes of CVCp･i･ during the reproductive cycle of dairy

COWS.

The present study revealed that during the different reproductive stages of healthy

dairy cattle, even though the CVCp･i･ changed drastically, except ln SOmefluctuations of

CVCave, CVCaveNL and CVCave/Ao, there were no slgnificant differences in the

latter parameters･ This flnding agreed with our previous results in which I demonstrated

30

that CVCaveNL and CVCave/Ao ratios were fixed values in both growlng and mature

healthy cows (chapter 2)･ Therefore these parameters could be applied as useful

indicators for the diagnosis of heart disease.

In conclusion, the CVCp･i･ of dairy cattle is related to heartbeatand reflected the

alteration of circulatory status of dairy cattle in different stages of reproductive cycle･

On the other hand, the CVC pulsation index was slgnificantly altered in pre-and

postpartum periods as well as during lactationand was also shown to coⅢ･elate with

shi允s in daily milk yield per month･ Additionally'the ratio of the average diameterof

the CVC to the length of the thoracic vertebrae and the diameterof the aorta are fixed

values in healthy cattle within any reproductive stage･

31

CVCp-0･48 + 0･99 'Heartt光at

i】

】

｢1【】｣

1

65･0｢;

1

･;:･

.::60.01

･

･

:

64.0 68.0 72.0 76.0

IIe artt*at

Fig･ 1 1 ･ Scatterplot was showlng relation for per minute pulsation of caudal vena cava to per minute heartbeat･

Graph is depicting linear regressionanalyses between per minute pulsation of caudal vena cavaand per minute

heartbeat in cows･ Equation for line is as follows; CVC pulsation: CVCp - 0･48+0･99xheartbeat, R2- 0･99, n-22,p<0･001･

CVCp: CVC pulsation･

Table3. Showlng the average diameter and pulsation index ofthoracic CVC, and the ratios of CVCave/Ao and CVCave/VL

CVCaVe(mm) CVCp.i. CVCaVe/Ao CVCaVe/VL

Dryperiod 27.70士3.95 42.13士10.97 0.61士0.09 0.43±0.07

4thWPP 29.32士5.74 33.73士14.23 0.65士0.13 0.46土0.09

10thWPP 27.48土4.53 38.55土12.72 0.61士0.ll 0.43土0.07

15tbWPP 28.56土5.58 41.90土10.37 0.63土0.13 0.45土0.10

25thWPP 30.lO土5.66 34.79土14.98

l∩

0.68土0.14 0.46士0.09

35tbWPP 30.24土5.12 43.46士11.23 0.69土0.13 0.47土0.08

40thWPP 30.59土5.05 43.35士10.80

uu

0.71士0.12 0.48士0.08

CVCave: average diameter of the caudal vena cava; CVCp.i.: pulsation index of CVC; Ao: average diameter of aorta;

VL: length of 8th thoracic vertebrae

DryPeriod 4廿IWPP IO81WPP 15廿IWPP 25廿IWPP 35廿1WPP 40廿1WPP

Experiment Period

Fig･ 12･ Showingthealterations of the average diameter and pulsation index ofCVC &om the dry period to

the 40th week postpartumincows; CVCave: average diameter of caudal vena cava; CVCp.i.: pulsation index of

caudalvena cava; WPP: week postpartum.

DryPeriod 4廿1WPP IO廿IWPP 15廿IWFP 25廿1WPP 35廿1WPP 40dlWPP

Expqiment Period

Fig･ 13･ Showing the alterations of the ratios of CVC average diameter to the diameter c'faorta andthe length

of 8dlthoracic vertebrae &om the dry period tothe 40th week postpartumin cows; CVCave: average diameter of

cvc; Ao: diameter of aorta; VL: 1engthof 8th thoracic vertebrae; WPP: week postpartum･

Chapter4

Dimensions and Dynamics of the Caudal Vena Cava and the Hepatic Vein Alter

Parturition and Lactation in Dairy Cattle

Introductiom

Vena cava morphology, highly compliant and low pressure, is often used to estimate

cardiac preload, because of its anatomic structure and relationship to the right a土rium (8,

30)･Anatomically, both the caudal vena cava (CVC) and hepatic vein (HV) lack valves,

thereby an increase in the systemic venous pressure is readily transmitted to the inferior

vena cava (ⅠVC) and the HV altering CVC diameter and collapsibility. Therefわre,

ultrasonographic measurement of the abdominal CVC iswidely used as a noninvasive

method fわr clinical practice to understand and track a patient-s haemodynamic status fわr

diagnosticand treatment purposes･ For instant, monitoring effect of treatment of

congestive heart failureand the diagnosis of various types of heart failure in human

medicine and small animal clinics are pe血med by measurlng the dimensionsand

dynamics of the abdominal CVC.

Furthermore, the HV is an important indicator for the diagnosis of cardiovascular

dysfunction･ Roobottom et all (77)reported that the hepatic venous pulsatility varies in

flow direction and veloclty, Which occurs during each cardiac cycle in the HV･ Size,

now veloclty Or PatternOfthe HV is innuenced by the pressure of the right atrium, the

hepatic parenchyma and changes in the thoracic and abdominal pressure by resplration

(1, 5, 11, 82)･Therefore, ultrasonographic measurement of the HV is used to diagnose

36

tricuspid valve insufrlCiency associated with right ventricular failure (42, 43), liver

dysfunction and tricuspid regurgitation (1), congestive cardiac insufrlCiency (3) and

congestive heart failure (31).

In dairy cows, the ultrasonographic image of the abdominal CVC is visible from the

intercostal space of the right side liver reglOn and triangular shaped in its cross section.

Braun U･and Gerber D･ (12) performed ultrasonographic examinations to measure the

size of CVC and HV for healthy cows of different ages, breeds and stages ofpregnancy･

Furthemore, the imaglng dilatation of the CVC and HV has been used in

ultrasonographic diagnosis of cattle with thrombosis in the CVC and HV (12, 14 and

61)･ In Chapter 3, I investigated the dimensionsand dynamics of the alterations of the

thoracic CVC by X-ray in dairy cows during reproductive cycle･ However, due to more

pressure in the abdomen, the abdominal CVC has more direct changes than that of the

thoracic CVC, even though it is the extension of the thoracic CVC anatomically･

Therefore, the aim of present study was to clarify whether the dimensions and dynamics

of the abdominal CVC and HV reflect pressural and hemodynamic alteration of

abdominal cavlty during different stages of reproductive cycle･

Materials and Methods

Animals･･ Twenty-two pregnant Holstein cows betweenages of 21 and 84 months

were previously subjected to serologicaland radiologlCal examinations to exclude

circulatory dysfunction and other diseases･ Scannlng Was done longitudinally on each

cow from the 35th week of gestation during the dry period throughout lactating period

37

of the 4th, loth, 15th, 25th, 35th, and 40也wpp.

UIErasonographic and Dowler examination･･ The ultrasonographic and Doppler

examinations were performed with an Aloka SSD-1700 (Aloka Co. Ltd., Tokyo, Japan)

by uslng a COnVeX real-time scamer on the right side of the abdomen while the cows

were standing as described by Braun U･ and Gerber D.(12).Hair was clipped between

the 1lth intercostal spaces and a handbreadth behind the last rib･ A鮎r the application of

transmission gel, the intercostal space was sca血ed by use of a 3.5MHz convex

transducer, beginnlng dorsally and progresslng Ventrally･ The texture of the visceral,

right kidney, liver, hepatic and portal vein were examined fわrhepa土ic or cardiovascular

disorders･ The ultrasonographic images were frozen when an approprlately shaped

intrahepatic CVC appeared in the monitor･ The approprlate meaSurementS Were then

made with ultrasonography and calipers by measurlng the maximal altitude and the base

dimension of this triangle to calculate the area of CVC (CVCare). The depth of CVC

(CVCdepth) was determined by measuring the distance between the base of the inverted

triangle of the CVC and the visceral peritoneum, the line on the ultrasonic wave that

passes through the apex of the inverted triangle (Fig.14).Finally, the flow velocity of

the major HV, which connects with the intrahepatic CVC and collectlng Veins, was

measured by Doppler uslng a 3･5MHz convex transducer･ A鮎r taking a longitudinal

section of the vessel, the sample volume of the Doppler system was placed in the

middle or the vessel, and the spectral wavefb-s were obtained･ The smallest possible

velocity scale and the lowest possible wall filter were used (Fig. 15). The Doppler

ultrasonograpbic studies were pe血med in all cases by the same examiner to avoid

interobseⅣer v∬iability･ This study was approved by the Animal Research Ethics

Committee of Obihiro Universlty OfAgriculture and Veterinary Medicine.

38

Statistical ana[ysL'sI Statisticalanalyses were made by corre-procedure and mixed

model procedures (The SAS System for Windows, v.8.2; SAS Institute Inc, Japan) for

repeated measurement by the followlng formula:

Yces-p+ Cc+ Ee + Ss +eecs

C-cow( 1-22)

E-Experiment number (1-7)

S-Season (1,2, 3, 4)

Eecs -random residual effect

A mixed model in SAS was used for analysis Ofvariance of CVCare, diameter and flow

velocity of the HV･ ARer significant F-tests (P < 0.05), least squares means were

compared in Scheffe's t-tests, the difference was considered statistically slgnificant

whenp < 0･05･ The HV was considered as a covariate, when the dependent variable was

CVCare, and vice versa･ Experiment number and season were treated as fixed effects,

and individual cows as random effects.

Results

In the present study, research proceeded continuously丘om the dry period of each

cow to the end of lactating period (approximately 40th wpp)･ The study was conducted

over one and half yearsand throughout the various season of Hokkaido. Evident

alterations in seasonal temperatures in Hokkaido were considered as a fixed effect for

the mixed model･ The results demonstrated that, seasonal variation is an lgnOrable flXed

39

effect in the present study･ Since the CVC and the major HV connect to each other

anatomically, and the hepatic blood flow into the CVC via the major HV, when one is

treated as a dependent variable, the other one is considered as a covariable effect.

As shownin Table 4, the average area of the intrahepatic CVC was 736.85土164.90

mm2 in the dry period, but was reduced to 583.71±164.97 mm2 in 4th wppゎ<0.01) in

Scheffe's t-tests･ The CVCare were 661･97士116･94, 666.26土181.47, 646.97土159.49,

633･60土141･38 and 676･38土228･11 mm2 in the loth, 15th, 25th, 35th and 40th wpll

respectively･ There were no differences detected within these values･ The intrahepatic

CVCdeptb were 128･43土11･70, 129･81土10･72, 132･11±11･57, 131.50土12.27,

136･98士12･36, 135･52土14･67 and 131･89±16･29mmin the dry period, and the 4th, loth,

15th, 25血, 35th and 40th wpp, respectively'and no differences were detected within any

oftbe values (Fig.16).

The average diameter of HV was 20･91土4･92 mm in the dry period, which was

reduced to 17･41士3･83 mm in the 4th wpp (ク<0･01) in Scheffe's t-testsI The average

diameters ofHV were 18.30士4.48, 19.30土4.25, 20.00土3.74, 21.05土4.21 and 22.21土5.70

mm in the loth, 15th, 25th, 35thand 40th wpp, respectively･ There was an increaslng

tendency from the 4th to 40thwpp of the lactating period, but no differences were

detected within them (Table4, Fig. 16).The flow velocity of HV was 22.13土4.82 cm/s

in the dry period and increased to 36.28土6.03cm/sわ<0.01)

in the 4th wpp. These

values reached peak of 37･64j=5･50 cm/s in the loth wpp and then declined from loth lo

40th wpp (35･64±6･43,33･42士6･62, 29･40±6･38 and 25.66土6.04 cm/s in 15th, 25tb, 35也

and 40th wpp,respectively)･

There were no differences detected within any of them

(Table 4, Fig. 16).

The average daily milk yield per month was 41･08土7･21 kg in the 4th wpp, with peak

40

values of 43･56土6･48 kg in the loth wpp (Table 4, Fig･16)･ Corre-procedure, used to

evaluate the coⅢ･elations betweenall parameters and milk yield, revealed that the

diameter ofHV negatively correlated to milk yield (r2-0.08,n-122, p<0.0015) (Fig.17).

The flow velocity of HV positively correlated to milk yield signiflCantly (r2-0.21,

n=122, p<0.0001) (Fig. 18).However, there was no difference detected between milk

yield and area ofCVC.

Discussion

The Scheffe's t-test indicates that there was a slgniflCant Change in abdominal CVC

area, diameter and flow veloclty Of HV in pre- and postpartum･ There was a high value

of CVC area and hepatic venous diameter in the dry period. However, in the 4th wpll

there was a dramatic reduction･ This phenomenon may be associated with the matemal

hormonaland hemodynamic variation, especially variation of cardiac output in pre-and

po stpartum.

During a mammal-s pregnancy there is an increase in levels of estrogen, progesterone

plasma aldosterone and renin activity which promotes sodium retention and an increase

in total body water (25)･The maternal blood volume begins to change from the flrSt

trimester, which continues into postpa仙m, then increases progressively, peaking at

approximately 30-50% above baseline by the third trimester in humans (92).Plasma and

blood volumes are increased during gestation in cows (73). The increase of blood

volume is associated with the elevated cardiac output, 30-50% above baseline by 25

weeks in humans (25). However, under steady-state conditions, venous retum must

equal cardiac output when averaged over time because the cardiovascular system is

41

essentially a closed loop･ Othe-ise, blood would accumulate in either the systemic or

pulmonary circulations･ Although cardiac output and venous retum are interdependent,

each can be independently regulated (62)･ From mid-pregnancy, the enlarged utems

compresses both the vena cava and the lower aorta. Obstruction of the CVC reduces

venous retum to the heart leading to a fall in cardiac output by as much as 24% towards

term (19)･ Thus the venous circulation often functions as a large reservoir where blood

can be "stored" while still in circulation･ This generally takes place in the larger veins

(such as the CVC) by a change in the diameter or shape of the veinsand helps to control

wild swings in blood pressure (30, 62).Furthemore, due to the anatomical structure ｡f

the CVCand the major HV connecting to each other, the increased total blood volume

and reduced venous returnmay cause dilationof the major HV and slgnificant

decelerationofhepaticflow veloclty in dry cows･

The hemodynamicchanges are most striking during labor

and immediately

POStPartum･ Most of the haemodynamicalterations that occur during pregnancy return

to baseline within 618 weeks aRer delivery, but it appears to be variable (72).Blood

volume and total body water decreased due to blood loss during delivery and

postpartum diuresis･ Postpartum diuresis peaks between the 2nd and5th

day aRer delivery

(68), simultaneously cardiac output decreases strikingly (approximately 28%) by 2

weeks a鮎r delivery (76)･However, the dimensions and dynamicsof the CVC vary with

the changes in total body water and circulatory blood volume (45, 55), which may be

influenced by the systemic, hepatic circulatory status and changes in the thoracic and

abdominal pressure (13, 65)･ Thus the changes in size of the CVC and =V in pre- and

postpartum will reflect the release of abdominal pressure in labor and the recovery of

venous retum.

42

In the present study, there was no correlation detected between milk yield and

abdominal CVC size･ However, the diameter of the major HV negatively correlated to

milk yield･ The flow veloclty Of the HV positively correlated to milk yield･ Braun U･

and Gerber D･(13) described a positive correlation between abdominal CVC size and

milk production, however, their results were obtained from the longest diameter of the

CVC and milk yield of individual cows, but this was absent in the present study･ In the

lactating period, it is well recognized that the blood volume and cardiac output of cows

is increased (32, 73),and simultaneously the distributionof blood volume, which flows

into mammary glands for milk secretion, was increased, and in the vena cavars retum,

there is no obstmction of the CVC by the enlarged utems･ Consequently, there is a no

statistically slgnificant increase, but there is a tendency for an increase in abdominal

CVCare, diameter and flow velocity of HV between 4th and loth wpp･ Furthermore,

there is a close correlation between dry matter intake and milk production in lactatlng

dairy cows (29)･One feature of the high-producing dairy cow is high dry matter intake.

However, the increased feed intake elevated liver bloodflow in lactating dairy cows

(80)･ Therefore, it is easy to understand why the flow velocity curve of the HV

corresponds to the curve ofmilk yieldand both correlated with each other slgnificantly･

There are few studies that describe ultrasonographic observation of the abdominal

CVC visualized as a triangular cross section in the 12th and eleventh intercostalspaces

in cows (12)･In the present study, the optimal view and biggest size of the CVC was

obseⅣed in the llth intercostal space in the dry period, and then moved to the 12th

intercostal space in the lactatlng Period･ However, there were no slgnificant differences

in the depth of abdominal CVC･ Though we observed alterations in the measurement of

the HV and a positional change in the liver due to the compression of the enlarglng

43

utems.

In conclusion, there were striking variations in the intrahepatic the CVC, diameter

and flow veloclty Of the major HV in pre-and-postpartum. The diameterandflow

veloclty Of the HV signi丘cantly correlated to milk yield in the lactatlng period･ The

dimensions and dynamics of the CVC and the HV reflect the alteration of circulation

status of dairy cattle in different stages of reproductive cycle. The present results may

offer a useful reference for the ultrasonographic diagnosis of circulative dysfunction of

dairy cattle.

44

Fig･14･ Showingthe ultrasonographic image of liver, shape, maximumand minimumlengthof infrahepatic

caudalvena cava (CVC),and the diameter of the hepatic vein (HV), as well as the depthof CVC

(CVCdepth) be measured.

Fig･ I5･ Showingthe position ofhepatic veinwhere the flow velocity of the hepatic vein was measured by Doppler.

Table4･ Showlng the average diameter and depth ofthoracic CVC, diameter and flowveloclty Ofhepatic vein and the daily

milk yield per month

～

CVCarea(mm2) CVCdepth(mm) HVdia(mm) HVfV(cm/s) MilkY(Kg)

Dryperiod

l】

∃736.85土164.90 128.43土11.70 20.91土4.92 【22.13士4.82

4thWPP F583.71士160.97 129.81士10.72 17.41士3.83 36.28土6.03 41.08土7.21

10thWPP

】】

∈661.97土116.94 132.11土11.57 18.30土4.48

芦

F37.64±5.50 43.56土6.48

15thWPP 666.26土181.47 131.50士12.27 19.30土4.25 35.64土6.43 38.01士7.20

25thWPP 646.97土159.49 136.98土12.36 20.00士3.74 33.42土6.62 30.99土7.27

35thWPP 633.60土141.38 135.52土14.67 21.05士4.21 29.40土6.38 27.45土5.76

40thWPP 676.38士228.ll 131.89士16.29

uH

22.21土5.70

CVCare: average area of CVC; CVCdepth: average depth of CVC; HVdia: average diameter of hepatic veln;

HVfv: now velocity ofhepatic vein; MilkY: milk yield･

Fig･16･ Showing the alterations of the average area of the abdominal caudal vena cava (CVC), diameterandflow velocityof

hepatic vein, depth of the caudalvena cava,and the daily milk yield per month from the dry period tothe 40thwpp in

cow; HVdia: diameter of the hepatic vein (rr-),HVfl:flow velocityof the hepatic vein (cm/s),Milk: daily milk yield

per month (Kg/d),CVCarea: average area of the CVC (mm2), cvcdepth: the depth of the CVC (mm).

HVdia -24.96 +10.15* MilkY

′ー

喜､ヽ■′

L

q>

ち重点

'B 20

iI

o｣1

o1

1L

r

【

10.011

● ●●

● ●

20.0 30.0 40.0 50.0

Milk Yield (Kg/叫

Fig･ 17･ Scatterplot showlng relation of the average diameter ofhepatic vein to daily milk volume of per month･

Graph is depicting linearregressionanalyses between the daily milk volume per monthand the diameter of hepatic

vein in cows･ Equation for line is as follows: HVdia - 24･9610･15x Milk Y, R2- 0･ 08, n-81,p<0･05･ HVdia: diameter of

the hepatic vein, Milk Y: daily milk yield per month･

ⅡⅤ付-19.50 +038* MilkY

● ●●

●+.. ●

/イ-//

//

T+

､50.01

喜40･01杏

'Bv I; 30･叫(∋

G]

>=

20

'01∠二二iii-~iiiii-

20.0 30.0 40,0 50.0

Milk Yield(Kg/叫

Fig･ 1 8･ Scatterplot showlng relation offlow velocity ofhepatic vein to daily milk volume per month･

Graph is depicting linear regression analyses between the daily milk volume per month and the flow velocity of

hepatic vein in cows･ Equation for line is as follows: HVfv-19･50+0･38x Milk Y, R2- 0･ 21, n-81, p<0･01･ HVfv:flow

velocity oftbe hepatic vein; Milk Y: daily milk yield per montb･

Chapter5

Intravascular Pressure of the Caudal Vena Cava Alters in Reproductive Cycle of

Dairy Cattle

IntrodⅦction

The vena cava is a highly compliant low-pressure capacity vessel (30). The

intravascularpressure of the vena cava is referred to as the central venous pressure

(CVP), which reflects the right atrial pressure and can be used to identifyhealthy

subjectsor ones with cardiac illness (9, 15, 84 and 98)･ The CVP may be influenced by

the abdominal pressure, blood volume, cardiac output, venous constriction and arterial

dilation (33),measurement ofa CVP can be helpful in the diagnosis and management of

a variety of critical illnesses and injuriesincluding trauma, burns,sepsis, COngeStive

heart failure, cardiogenic shock, traumatic brain injuryin human (22,28, 36, 75, 86, 87

and 93)･However, due to the variation of the CVP, the dimensions and dynamics of the

inferior vena cava (IVC), which correspond to the caudal vena cava (CVC) of cows, are

altered in its configuration, width and respiratory movements. Therefore insteadof

estimatlng the CVP, measurlng the inferior vena caval diameter is frequently used as a

noninvasive method in clinical practice to assess volume status and cardiac preload (2,

18).

In veterinary clinical practice, elevated CVP is regard as a prlnClpal clinical

diagnosticpoint for right heart failure (21),and alteration of CVP is also used as a guide

to fluid therapy which suggests possible fluid overload or decreased fluid administration

51

during infusion or hemodialysis in small animals (26). In cattle, our previous study

demonstrated that the radiographic evaluation of thoracic CVC provides a useful means

of the diagnosing heart disease in dairy cows (chapter 2). In addition, ultrasonographic

measurement of the abdominal CVC reveals alteration in reproductive stages in dairy

cows (chapter 4)･ However, a cow being an industrial animal, the raising of milk could

be achieved by ensurlng One Calf per year丘om each cow･ No-ally, a cow can

conceive between 60 and 90 days post-calving･ Therefわre, the pregnant cow carries

double burden of producing large quantities of milk and carrylng her next calf. Within

the same time there are severe changes in abdominal pressure and blood volume. Hence,

there is need to clarify the alteration of intravascular pressure of CVC, and whether this

is related to the dimensions and dynamics of CVC in reproductive cycle of dairy cows･

In the present study, the intravascular mean pressure of abdominal and thoracic CVC,

the mean pressure of right atrium and ventricle as well as the mean pressure ofjugular

vein were dete-ined fわr 35 weeks of gestation during the dry period, as well as during

the lactatingperiod of the 4th, loth, 15thand 35th wpp, respectively･

Materialsand Methods

Animals･'Seven cows (between 20and 72 months of age 44.57士19.75) out of the

twenty-two pregnant Holstein cows that were examined in chapters 3 and 4 were

randomly selected to for catheterization promptly aRer a fluoroscopIC test.

Measurements were done longitudinally for each cow from the dry period throughout

the lactatlng Period of the 4th, loth, 15th, and 35th wpp.

52

Catheterization･･ The measurements were performed in a large animal X-ray mass

scanning car equipped withanindustrialfluoroscope (MG321 ; Hitachi Medico, Tokyo)

with a camera and a patient monitor･ A鮎r each cow was placed in the car, and

restrained in a standing position in the middle or the stock, the head of the cow was

restrained on the right side of the stock･ One-third of the way down the neck the hair

was clipped and the skin shaved over the le氏jugularvein and 5mm long lnCision was

made using a scalpel･ Then, an introducer was inserted (7Fr diameter), and a guiding

catheter (angiogr叩hy catheter,丘eestyle, length 100 cm, Medikit, Japan) was advanced

into the jugularvein･ This catheter hasaninserted guidewire to avoid entrapment of the

catheter tip･ Using nuoroscopICProcedures, the catheter was positioned in the

abdominal and thoracic CVC (Fig･ 19),right atrium, right ventricular, and jugularvein,

respectively･ Five milliliters of physiologlCal saline with l% heparin sodium was

Injected beforeeach pressure recording at every site to exclude catheter entrapment･

Venous pressure was monitored on the patient monitor BP-508 (Colin Co., Ltd., Aichi,

Japan) via an electronic transducer fixed at the level of the right atrium (under

fluoroscopicguidance) and after stabilization all recordings were printed for later

analysis.

Statistical Analysis: Linear regression analyses and one-way analysュs Of variance

(ANOVA) for comparison of means between the repeated correlated samples were

performed to analyze all related data using the SPSS analysis software (SPSS 12.0.J fo,

Windows Advanced Models, SPSS Inc., Japan), and p values of less than 0.05 were

considered statistically slgnificant.

The other data used for the linear regression analyses were drawn from the previously

described studies in chapters 2 and 3, in which the measured parameters included the

53

average diameter and pulsation index of the thoracic CVC, as well as the average area

of abdominal CVC.

Results

As shown in Table 5, the mean pressure of abdominal CVC was the highest (9.00±

2･70mmHg)

in the dry period,and then declined to 5.14土1.35 mmHg,p<0.01 in the 4th

WPP･ ThereaRer, there was a slgniflCant increase in this value in the loth wpp, and

remained constant up to the 15th wpp (7･43土0･53and 7･43土0･1･9 mmHg, bothp'0.05).

on the 35th wpp the value declined to 5･86士0･69 mm=g, and this value was

significantly lower than in the dry period Q?<0.01)(Fig20).

The mean pressure of the thoracic CVC was highest (2.29士2.75 mmHg) in the dry

period, which declined to-0･86il･35 mmHg ln the 4th wpp, and the differences

between these values was significant (ク<0･05)･ Thereafter, there was increasing

tendency in the loth wpp (1･43土1･51mmHg),and a decreasing tendency until the 35th

WPP (0･86土0･69mmHg in the 15thwpp and O･29土0･49mmHg in the 35th wpp) (Table

5,Fig.20).

There were some fluctuations observed in the mean pressure of the right atrium and

right ventricle, as well as Jugular vein pressure, and these fluctuations were not

statistically significant during the experimental period (Table 5, Fig. 20). However, the

linear regression analysュs revealed that there was a slgni丘cant correlation between the

meanpressure of the right atrium and the jugularvein (Table 6 and Fig. 21).

The mean pressure of the abdominal CVC was slgniflCantly higher than that of the

thoracic CVC and the right atrium (both p<0･001)･ However, the mean pressure of the

54

tboracic CVC was correlated to the mean pressure of the abdominal CVC (r2-0.42,

n=35, p<0･01) (Table 6 and Fig･ 22)and the mean pressure of the right atrium (r2-0.27,

n=35,p<0･01), respectively (Table 6and Fig. 23).

The linear regression analyses showed that the mean pressure of the abdominal CVC

positively correlated with the area of abdominal CVC (r2-0.28,n-35, p<0.01) (Table 6

and Fig･ 24), and the pulsation index ofthoracic CVC (r2-0.12,n-35, p<0.05) (Table 6

and Fig･ 25)･ However, the mean pressure of the abdominal CVC negatively correlated

with the diameter of thoracic CVC (r2-0･20, n-35, p<0.01) (Table 6 and Fig. 26). In

addition, the mean pressure of the thoracic CVC coⅢ･elated with the pulsation index of

thoracic CVC (r2-0･11,n-35,p<0･05) (Table 6and Fig. 27) as well as the average area

of the abdominal CVC (r2-0･14,n-35,p<0.05) (Table6 and Fig. 28). For both the mean

pressure of the abdominal and thoracic CVC, there was a positive correlation with the

average daily milk yield per month (r2-0･16,p<0.05 for abdominal CVC, and r2-0.04,

p<0･05 for thoracic CVC, bothn-35),respectively.

Discussion:

In the present study, 1t Was ObseⅣed that there was a pressure gradient in systemic

venous return, which mows via the abdominal and thoracic CVC to the right atrium,

even when the pressures were altered by pregnancy and lactation･ This result supports

Lin, M･-C･(48) who reported that there was a decreasinggradient in mean pressure of

the inferior vena cava towards the right atrium, and higher than that of the mean

pressure of the right atrium in spontaneously breathingchildren･

55

Among the mean pressures measured in the present study, the alterations of the mean

pressure of the abdominal CVC were the most drastic in the reproductive cycle･ The

increase in mean pressure of the abdominal and tboracic CVC during pregnancy ln the

present study was probably due to the increased abdominal pressure as a result of the

gravid uterus (69), because there is a close rela土ionsbip between intra-abdominal

pressure and pressure in the IVC (70, 74)･ The gravid uterus, by causing a functional

obstruction of the CVC and increaslng lntra-thoracic pressure by pushing the diaphragm,

diminishes the venous returnto the heartand decreases preload as well as cardiac output･

In addition, elevated intra-abdominal pressure compresses the abdominal aorta and

increases systemic vascular resistance, thereby lnCreaSlng a鮎rload and decreaslng

cardiac output (37, 46 and 67). On the other hand, plasma and blood volumes are

increased during gestation of cows (73). Further, the augmented blood volume is

another main reason for the increased CVP (54)･After delivery, the mean pressures of

the abdominal and thoracic CVC are reduced as a result of decreased intra_abdominal

pressure by the retraction of the deflated uterus･ Simultaneously bloodvolume and total

body water were decreased because of blood loss during delivery and postpartum

diuresis (68).

During the lactatingperiod, it is well recognized that the blood volume and cardiac

output of cows are increased (32, 73),consequently, the mean pressure of abdominal

CVC increased during the lacta土1ng period and these values positively correlated with

the daily milk yield.

In the present study, the mean pressure of the abdominal and thoracic CVC positively

correlated with the pulsation index of the thoracic CVC, this result supports the work of

56

Minutiello L. (59) who demonstrated that the caval index may indicate normal CVP and

was inversely related to an elevated value of CVP in heart failure patient.

Much of the literature has demonstrated that the measurement of abdominal CVP can

replace the measurement of thoracic CVP because this reflects the pressure in the right

atrium in critically illpatients or cardiac surgical patients (17, 38, 50, 52, 64 and 98). In

the present study, it was obseⅣed that the mean pressure of the abdominal CVC was

indirectly correlated, not directly as丘rst supposed, to the mean pressure of the right

atrium via the thoracic CVC. Namely, the mean pressure of both the abdominal CVC

and the right atrium were positively correlated with the mean pressure of the thoracic

CVC. This result supports the findings of Jue J. et al. (39) who demonstrated that the

correlation between insplratOry Change in the IVC diameter and mean right atrial

pressure was poor in patients undergolng mechanical ventilation･ The mean pressure of

the abdominaland thoracic CVC significantly increased during pregnancy or lactation･

According to the Frank-Starling mechanism, the increased venous pressure and blood

volume led to an increase in cardiac preload. Neve血eless, there were no alterations

detected in the mean pressure of the right atrium and the right ventricle･ This

phenomenon is considered as a compensatory constrictlng tendency of the thoracic

CVC, which serves as a mechanism for reducing ventricular fllling to alleviate the

cardiac preload･ Our previous study demonstrated that the average diameter of the

thoracic CVC was not dilated but there is a constrictlng tendency ln pregnancy, Which

augments the mean pressure of the thoracic CVC.

In conclusion, the mean pressures of the abdominal and the thoracic CVC are well

reflected in the hemodynamic status of healthy dairy cattle in different stages of

reproductive cycle･ Radiographic pulsation index of the thoracic CVC may indicate an

57

alteration of CVP. An ultrasonographic evaluation of the abdominal CVC may be useful

as a non-invasive estimation of CVP in healthy dairy cows. However, more studies are

needed to evaluate these flndings.

58

Fig.19. Catheterization; Showing the tip of the catheter which was inside of the thoracic caudalvena

cava, CVC: caudalvena cava, R-Atrium:right atrium.

Table5･ Showlng the mean pressure of abdominal and thoracic CVC, the mean pressure of right atrial

and ventricular, as well as the mean pressure ofjugularvein

Unit: mmHg

】ACVPTCVP

【

∩

RAP RVP JVP

Dryperiod 】9.00土2.712.29士2.75 弓1.14土3.29

19.00士1.63

∃

0.14土0.38

4tbWPP

iH‖

】5.14土1.35 -0.86土1.35 -1.29土1.5019.83士0.75 0.00士0.00

10thWPP 7.43士0.53 【1.43土1.51

ち1.00士2.16 NT 0.00土0.00

15thWPP 7.43土1.90 0.86土0.69 0.14土0.69 NT 0.0000

35thWPP 5.86士0.69 0.29士0.49 0.00土0.00 NT NT

ACVP: mean pressure of abdominal CVC; TCVP: mean pressure of the tboracic CVC; RAP: mean pressure of right atrium;

JVP: mean pressure ofjugularveln; NT: None tested･

⊂i

bJ)

=

∈

∈

SL

蛋丘⊂

蛋≡

Dry Pqiod 4th W PP loth WPP 15th W PP 35th W PP

Expqirnent period

Fig･20 Meanpressures of the abdominal CVC,thoracic CVC,right atriumand jugularveinduring reproductive cycle

Showing thealterations of the mean pressures of the abdominalandthoracic CVC,the meanpressure of right atriumand jugular

vein from the dry period tothe 35th week postparttmlincows; ACVP: meanpressure of abdominalCVC; TCVP: meanpressure of

thoracic CVC; RAP meanpressure of rightatrium; JVP: mean pressure ofjugularpressure; WPP: week postpartum.

Table6. Correlations between ACVP, TCVP, RAP, JVP, CVCp･i･, CVCave and CVCare

ACVP TCVCP』RAPJVP CVCp.i. cvcave≒CVCare

ACVP pearsonーsco汀elationcoe岱cient 1

35

.647(**) .156 .292 .342(*) -.445(**) .528(**)P

.000 .371 .089 .044 .007 .001

N 35 35 35 35 35 35

TCVI} pearson'scorrelationcoefficient.647(**)

1

35

.515(**) .210 .334(*) -.208 .371(*)P

.000 .002 .227 .050 .230 .028

N 35 35】 35 35 35 35

RAP pearsonTscorrelationcoefficient.l56 .515(**)

1

35

.480(**)-.029 .135 -.148

P.371 .002 .004 ･871⊆ .438.397

N 35 35 35 35 35 PIPJVP pearson'scorrelationcoefficient

.292 .210 .480(**)1

I35

.039 .13l .079

P.089 .227 .004 .825 .455

】.65l

N 35 35 35 35 35 35

CVCp.i. pearsonTscorrelationcoefficient.342(*) .334(*) -.029 ,039

1t-.531(**).355(*)

P.044 .050 .871 .825

35

.001 .037

N 35 35 35 35 35 35

CVCaVe pearsonlscorrelationcoefficient-.445(**) -.208 .135 .131 -.531(**)

1-,648(**)

P

･o冒;卜2…;.438.455 暮001∃

.000

I35i

N 35 35 35岳35

CVCare pearsonfscorrelationcoefficient.528(**) .371(*) -.148 .079 .355(*) -.648(**)

1

35

P.001 .028 .397 .651 .037 .000

N 35 35 35 3535 35

owlngthecorrelationsbetweenmeanpressureofabdominalandtboracicCVC,themeanpressureofrightatrlum,t

meanpressure of jugularvein, diameter and pulsation index ofthoracic CVC and the area of abdominal CVC･**

p'0･01 ,

*p<0.05.

TCVP = 0.90 + 0.65 * RAP

育≡

ヽ-′

E≡

>U!=

-4.0 -2.0 0.0 2.0 4.0

RAP (mmI海)

Fig･21 ･ Scatterplot showlng the relation of the meanpressure right atriumto the meanpressure ofthoracic CVC

Graph is depicting linear regressionanalyses between the meanpressure of right atriumand the meanpressure of

thoracic CVC in cows･ Equation for line is as follows: TCVP - 0･90+0･65x RAP, R2- 0･27, n-35,p<0.01. TCVP: Mean

pressure ofthoracic CVC, RAP: Meanpressure of right atrium

TCVP=-3.15+0.57 * ACVP

育書

ヽ一1′

P<

>･Uト

4.0 6.0 8.0 10.0 12.0

ACVP (m山Hg)

Fig･22･ Scatterplot showlng the relation of the meanpressure of abdominal CVC to the meanpressure ofthoracic CVC

Graph is depicting linear regressionanalyses between the meanpressure of abdominal CVCand the meanpressure of

thoracic CVC in cows･ Equation for line is as follows: TCVP -

-3･15+o･57xACVP, R2- 0･42, n-35, p<0･01･ TCVP: Mean

pressure of tboracic CVC, ACVP: Mean pressure of abdominal CVC

JVP-0.19 +0.46* RAP

局

i≡

ヽ一′

E'g

ー4.0 -2.0 0.0 2.0 4.0

RAP (mmI屯)

Fig.23. Scatterplot showlng the relation of the meanpressure right atriumto the meanpressure ofjugularvein

Graph is depicting linear regression analyses between the mean pressure of abdominal CVC and也e mean pressure

ofthoracic CVC in cows. Equation for line is as follows: JVP -0.19+0.46x RAP, R2- 0.23, n-35,p<0.01. RAP: Mean

pressure of right atrium; JVP: Meanpressure of jugularveln,

CVCare =358.88 + 48.35* ACVP

4 6 8 10 12

ACVP (mdTg)

官1000己Eコ

∈≡

ヽ一1/

4) 750h

cIU>U

Fig･24･ Scatterplot showing the relation of the meanpressure ofabdominal CVC to the average area of abdominal CVC

Grapb is depicting linear regression analyses between the average area of abdo血nal CVC and the mean pressure of

abdominal CVC in cows･ Equation for line is as follows: CVCare - 358･88+48･35x ACVP, R2- 0･28, n-35, p<0･01.

CVCare: Area ofAbdominal CVC, ACVP: Abdominal CVC pressure.

CVC〆=19.89+231 * ACVP

4.0 6.0 8.0 10.0 12.0

ACVP (mn止Ig)

Fig･25･ Scatterplot showlng the relation of the meanpressure of abdominalCVC to the pulsation of the thoracic CVC

Graph is depicting linear regressionanalyses between the meanpressure of abdominal CVCand the pulsation index of

thoracic CVC in cows･ Equation for line is as follows: CVCp･i･ - 19･89+2･31x ACVP, R2- 0･12, n-35,p<0･05･ CVCp･i･ :

Pulsation index ofthoracic CVC, ACVP: Meanpressure of abdominal CVC.

CVCaw =43.31 +-1.53*

ACW

4暮0 6.0 8.0 10.0 12.0

A C∀P(mmHg)

Fig･26･ Scatterplot showlng the relation of the meanpressure of abdominal CVC to the diameter ofthoracic CVC

Graph is depicting linearregressionanalyses between the average diameter of thoracic CVCand the meanpressure

ofabdominal CVC in cows･ Equation for line is as follows: CVCare - 358･88+48･35x ACVP, R2- 0･28, n-35,p<0.01.

CVCave: Average diameter of thoracic CVC, ACVP: Meanpressure of abdominal CVC.

CVCare - 664.0S + 38.48 * TCVP

Ej己･k

喜ヽ_′

4)

L

CI

UiU

-2.00.0 2.0 4.0 6.0

TCVP (nmHg)

Fig.27 Scatterplot showlng the relation of the meanpressure ofthoracic CVC to the area of abdominal CVC

Graph is depicting linear regressionanalyses between the meanpressure of thoracic CVCand the average area of

abdominal CVC in cows. Equation for line is as follows: CVCare - 664.08+38.48x TCVP, R2= 0･14, n=35, p<0･01･

CVCare: Average of area of abdominal CVC, ACVP: Meanpressure ofthoracic CVC･

CVCpi =33.SS+256* TCVP

-2.00.0 2.0 4.0 6.0

TCVP (皿ⅡnⅡg)

Fig･28 Scatterplot showing the relation of the meanpressure of thoracic CVC to the pulsation ofthoracic CVC

Graph is depicting linearregressionanalyses between the meanpressure of thoracic CVCand the pulsation index of

abdominal CVC in cows･ Equation for line is as follows: CVCp･i･ - 33･88+2･56x TCVP, R2- 0･11, n-35, p<0･05.

CVCp･i･: Pulsation index orthoracic CVC, ACVP: Mean pressure oftboracic CVC.

Chapter6

The Climical Application of FluoroscopIC and tJltrasonographic Measurement of●

the Caudal Vena Cava in Dairy Cattle

Introduction

The vena cava is a highly compliant low-pressure capacity vessel (30). The

intravascular pressure of vena cava is also referred to as the central venous pressure

(CVP), which indicates theright atrial pressureand canbe used to identifya healthy

subjector one with circulatory dys血nction (10, 15, 84and 98). Therefore, CVP is

frequently used in clinical practice to assess haemodynamic statusand cardiac preload

for diagnosticand treatment purposes. Knowledge of a patient's CVP canbe helpful in

the diagnosisand management of a variety of critical illnessesand injuriesincluding

trauma, bums, sepsis, COngeStive heart failure, cardiogenic shockand others. However,

instead of estimatingthe CVP, measunngthe diameter of the IVC, which corresponds to

the CVC of cows, is frequently used as a nominvasive method in clinical practice to

evaluate volume statusand cardiac preload (2,98).Consequently, the dimensionsand

dynamics of IVC, including conflguration, widthand respiratory movement alterations,

depend on the variations of CVP.

In a previous study, I demonstrated that the sizeand pulsation of the CVC provides a

useful means of diagnosing cows with cardiac disease (Chapter 2). Thereafter, the

alterations offluoroscopIC Or ultrasonographic dimensionsand dynamics of the CVC in

dairy cows during the different stages of single reproductive cycle were measured to

establish their basic parameters (Chapters3and 4).In addition, the correlations between

71

CVPand the dimensions or dynamics of CVC were investigated (Chapter5).The aim of

this chapter is to demonstrate that thefluoroscopICand ultrasonographic measurement

of the CVC and HV could provide a useful means of diagnoslng Circulatory

dysfunctions in dairy cows.

Material and Methods

Alu'maLsI Twenty-three Holstein dairy cows between the ages of 15and ll 1 months

(meaniSD: 44･17士21･87months)and suspected of having circulatory dysfunctions

were selected based on their climical symptoms, serological tests results,and

electrocardiographic records. The cows were obtained from various farms in Hokkaido

and then transported to the teaching hospital of Obihiro University of Agricultureand

Veterinary Medicine･ I did our examinationsand then the cows were slaughteredand

necropsleS done･ Postmortem findings revealed that 7 cows had vegetative endocarditis,

2 cows had traumatic pericarditis, 3 cows had septal defect, 4 cows had pericardial

e凪1Sion, 2 cows hadthoracic e乱sionand 5 cows had cardiomyopathy･

Amongthe twenty-three cowswith circulatory dysfunctions, the intra-cardiovascular

pressures were measured in 10 cows,and the parameters of the thoracic CVC were

measured by X-ray in 15 cows. In addition, the parameters of the abdominal CVCand

HV were measured in 12 cows by ultrasound.

X-ray scannzng examination･･ The X-ray scaJmlng examination was performed with

●

anindustrialfluoroscope (MG321 ; Hitachi Medico, Tokyo) as described in Chapter 2.

The following parameters were measured: 1) CVCmaxand CVCmin at the end of

expirationand 2) the VLand Ao. The later parameters were measured in order to

72

compare body structures, which are considered not to be directly affected by alteration

of the CVC, butare positioned inthe same intercostal spaces as the location of the CVC

measurements. Fromthe above measurements, the CVCaveand CVCp.i., the ratios of

CVCave/Ao, CVCave/VL, and Ao/VL were then calculated same as in chapter 2.

CatheLerization.･ The same as in chapter 5.

UItrasonographic and DoLIPler examinationI The ultrasonographicand Doppler

examinations were performed withanAloka SSD-1700 (ALOKA Co. Ltd, Tokyo,

Japan) as described in Chapter 4. This study was approved by the Animal Research

Ethics Committee of Obihiro Umiversity ofAgricultureand Veterinary Medicine.

Slatistical ann(ys良二The data derived丘omthe 22 healthy cows in the previous study

were applied as a basic data to assess the data obtained from the clinical subjectsin the

present study. Independent-sample t-tests were performed toanalyze all related data

using the SPSSanalysis software (SPSS 12.0.J for Windows Advanced Models, SPSS

Inc., Japan).p values of less then 0.05 were considered statistically signiflCant.

ResⅦ1ts

As shown in Fig. 29,也e CVCave in the test group (42.58士11.09mm) was

significantly higher (p<0･001)thanthat of the healthy control group (28.89土5.17mm).

In addition, the CVC pulsation index of the test group (2.8i5.97)was sigmificantly

lower b<0.0001) thanthat of the healthy group (36.15土13.47).The ratios of

CVCave/VL and CVCave/Ao in也e test group (0.71土0.13and 1.11士0.21)were

significantly higher (bothp<0.0001)thanthat of the healthy control group (0.45士0.08

and 0.64土0.12)(Fig.30).

73

As shoⅥm in Fig. 31 the CVCare in the test group (1828.81土521.27mm2) was

signiflCantly higher Q?<0.01) thanthat of the healthy control group (656･63土159･38

mm2), while the images of the abdominal CVC changed from the original triangular

shape toanelliptical or circularone･ In addition, the diameter of the HV in the test

group (31.71土7.90mm) was sigmificantly higher (p<0.01) thanthat of healthy group

(19.74土4.57mm) (Fig.32).

As shownin Fig. 33, the meanintravascular pressure of the abdominal CVC (ACVP)

in the test group (16.22士9.80mmHg) was sigmificantly higher Q?<0.01)thanthat of the

healthy control group (6.97土2.06mmHg),and the meanpressure of the thoracic CVC

(TVCP) of the test group (10.10土11.05 mmHg) was significantly higher (p<0･001) than

that of the healthy control group (0.80士1.83mmHg).The meanright atrial pressure

(RAP) in the test group (17.43土8.68mmHg) was sigmificantly higher (p<0･001) than

that of the healthy control group (0.20i2.00mmHg),however there were no statistically

slgniflCant differences detected in the meanright ventricle pressure between the test

group (27.22土17.68mmHg)and the healthy group (19.38土1.33mmHg).

The mean intravascular pressure of both ACVP and TCVP increased in 5 out of 10

cows in the test group (ACVP: 24.60士5.32 mmHgand TCVP: 19.60土6.50mmHg),and

the values were significantly higher (both p<0.001) thanthat of the healthy group

(ACVP: 6.97土2.06 mmHg,and TCVP: 0.80士1.83 mmHg) (Fig.34).However, the RAP

increased in 7 out of 10 cows in the test group (19.OO土古.30mHg), and itsvalues were

significantly higher (p<0.001)thanthat of the healthy control group (0.20土1.99mmHg)

(Fig.35).In addition, the meanpressure of the rightventricle (RVP) increased in 4 out

of 10 cows withinthe test group (41.25士18.77 mmHg),and the values were

significantly higher (p<0.01)thanthat of the healthy control group (19.38土1.33mmHg).

74

However,也e mean pressure of the jugularvein (JVP) increased in 2 o山of 10 cows in

the test group (23.00±7.55mmHg),and the values were significantly higher (p<0･001)

thanthat of the healthy group (0.05土0.21mmHg) (Fig･36)･

Discussions

In the present study, the ultrasonographic examinations performed in 12 cows with

circulatory dys氏mctions showed that the both the abdominal CVC and the HV were

highly dilated while the ultrasonographic cross sectional image of the abdominal CVC

cbanged丘om a triangular sh叩e tO an elliptical or circular one. In Chapter 5, I described

the phenomenon that the abdominal CVCand HV were dilated in the dry period of the

cows due to the compression of the enlarged utems and increased blood volume. During

this period, however, the ultrasonographic cross section of the abdominal CVC

maintained its triangularshape.

In thefluoroscopIC examinations, the thoracic CVC of the test group was highly

dilated while its pulsation disappeared in 12 cowsand became weakerin 3 cows out of

15 cows tested. Tberefbre,也e CVCave/VL and CVCave/Ao ratios were slgni丘cantly

increased. This result supports the conclusion documented in Chapter 2, in which

demonstrates that the dilatation of CVC, as well as, the disappearance or weakness of

pulsation are slgnS Ofheart disease in cows. In addition, this result is in accordance with

Minutiello L. (58) who describedthat a caval index < 20% is related toanelevated

value of CVP,and inversely related to meanCVP in humanpatients.

In the present study, some of the cows showed signs ofanincrease in the

cardiovascularpressure but the necropsy demonstrated that allthe cows had circulatory

75

dysfunctions. The intra-cardiovascular pressure was measured in a total of 10 cows; the

increase inright atrial pressure appeared much earlier thanthe CVP (boththe ACVPand

TCVP)and the JVP. The increase in RAP may indicate a corresponding increase in

cardiac preloads in cowswith circulatory dysfunction (23).However, the vena cava

being a compliant vessel, which is a typical compensatory mechanism, serves to dilate

its size in order to increase its storage capacity to relieve the cardiac load. Never也eless,

when the cardiac preload is in excess of the vena caval compensational capability, the

i山ravascular pressures begin to increase and remain at a high value (62).

In the present study, thefluoroscopIC measurement Of the thoracic CVC were dilated

while its pulsation became weaker or even disappeared,and the ultrasonographic

dimensions of the abdominal CVC and HV were dilated while the shape of the

abdominal CVC was altered in cowswith circulatory dysfunctions. This phenomenon

proved that thefluoroscopICand ultrasonographic measurement of the CVC was a

useful method for the diagnosis of circulatory dys血nction. However, thefluoroscopIC

test for largeanimals requiredanespecially powerful apparatus with a transport system

designed to protect people from X-ray radiation. Instead of afluoroscopIC apparatus, the

ultrasonographic instrument is broadly used in clinical diagnosis because of its safety

and convenience. Therefわre, the ultrasonograpbic measureme山of the abdominal CVC

and HV isaneffective method for the diagnosis of circulatory dysfunctions.

In conclusion, instead of measunng the intra-cardiovascular pressure, the

且uoroscoplC and ultrasonograpbic measureme山of the dimensions and dynamics of the

abdominal or thoracic CVC are useful methods forthe diagnosis of dairy cows with

circulatory dysfunctions, especially,the ultrasonographic measurement for CVCand HV,

re spective 1y.

76

I cvcave ) cvcp.i.

Control Test

Fig･29 Comparison of average diameter and pulsationindex of the CVC in healthand cowswithcirculatory dysfunctions

The average diameter (CVCave)and pulsation index of the CVC (CVCpj.)inhealthcows (n-35) and cows with

circulatory dysfunctions (n-15)I The boxplots display the median, 25thpercentile, 75thpercentile, and smal1estand

largest values･ Outliers (outsidevalues)aredesignatedwitha dotand extremum (extreme value)are designedwitha star.

I cVCaveAo I CVCaveNL

C ontTOl Test

Fig30 Comparison forthe ratio ofCVCave tothe Aoand VL in healthand cowswith circulatory dysfunctions

Ratios of CVCave to Ao (CVCave/Ao)and VL (CVCaveNL) in health (n-35)and cowswithcirculatory

dysfunctions (A-15)･ The boxplots displaythe median, 25thpercentile, 75thpercentile,and smallestand largest

values･ Outliers (outsidevalues) are designated with a dotand extremum(extreme value)are designed witha star.

2500.0･

′-■ヽ

≡≡き∃

≡

旦(pLc<

UiU

2000.0-

1500.0･

1000.0---早

500.0-

ContI℃1 Test

Fig･3 1 Comparison for the average area of infrahepatic CVC in health and cows with circulatory dysfunctions

The average area of the abdominal caudal vena cava (CVCare) in health control (n-35) and cows with

circulatory dysfunctions (n-12). The boxplots display the median, 25th percentile, 75th percentile, and smallest

and largest values. Outliers (outsidevalues) are designated with a dot･

50.0-

EiJ

≡

≡ヽ-/

●

e弓

'i=>･=

30.0-

20.0-

10.0-

Co IItm I Test

Fig.32 Comparison for the average diameter of hepatic vein in health and cows with circulatory dysfunctions

The average diameter of the hepatic vein in health cows (n-35) and cows with circulatory dysfunctions (n-12)･

The boxplots display the median, 25th percentile, 75th percentile, and smallest and largest values. Outliers (outside

values)are designated with a dot and extremum (extreme value) are designed with a star.

bb

=

∈

≡

4)

コ

I)

>

Control Test

Fig133 Comparison forthe CVP and RAP in healthand cowswith circulatory dysfunctions

The meanpressure of the abdominalCVC (ACVP),thoracic CVC (TCVP)andtheright atrium(RAP)inhealthy

contral(n=35)and cowswithcirculatory dys丘mctions (n-10)IThe boxplots display the median, 25thpercentile, 75th

percentile, and smallestand largest values･ Outliers (outside values)are designatedwith a dot. Extremum (extreme

value)are designedwitha star.

bD

=

∈

∈

q)コ

13>

Contro一 Test

Fig･34 Comparison forthe mean pressure of the abdominaland thoracic CVCinhealthy control and cowswith elevated CVP

The mean pressure of the abdom血1 (ACVP) and thoracic CVC (TCVP) in health cows (n-35)and cowswithelevated central

venous pressure (n-5)･ The boxplots displaythe median, 25th percemile, 75th percentile,and smallest and largest values･ Outliers

(outsidevalues)are designated witha dot. Extremum(extreme value) are designedwitha star･

二岩;

★

★

★

-X-

★

★

+

*

C on仕o I Test

Fig･35 Comparison for the mean pressure of right atrium in health and cows with elevated right atrial pressure

The mean pressure of the right atrial pressure in health cows (n-35) and cows with elevated right atrial pressure

(n-7)･The boxplots display the median, 25th percentile, 75th percentile, and smallest and largest values･ Extremum

(extreme value) are designed witha star･

50.0-

Jt5L)

=

≡ 40.0一

旦(i

>Fi30.0-

20. 0- --･⊥--右

O

C onb･o 1

----

:

_-

---千Te st

Fig･36 Comparison fわrthe RVP in health and cows with elevatedRVP

The mean pressure of the right ventricular (RVP) in health cows (n-14) and cows with elevated jugularvein pressure (n-4)･The

boxplots display the median, 25th percentile, 75th percentile,and smallest and largest values･ Outliers (outsidevalues)are designated

withadot.

30.0一

畜20･0-∈

主

星1｡.._

～

C onb･o 1 Test

Fig.37 Comparison for the JVP in health and cows with elevated JVP

The mean pressure of the jugular vein (JVP) in health cows (n-28) and cows with elevated jugular vein pressure (n-3). The

boxplots display the median, 25th percentile, 75th percentile, and smallest and largestvalues. Extremum (extremevalue)are designed

withastar.

Chapter 7

General discussion and conclusion

It is well known that the vena cava is a highly compliant low-pressure capaclty Vessel

(30). Its intravascular pressure is referred as CVP. CVP is an important concept in

clinical cardiology because it is a major determinant of the filling pressureand therefore

the preload of the right ventricle, which regulates stroke volume through the

Frank-Starling mechanism. However, the change in CVP (ACVP) is determined by a

corresponding change in volume (△Ⅴ)of blood within the vena cava divided by the

compliance (Cv) of the these veins according to the fわllowing Equation:

△CVP - △Ⅴ / Cv.

Therefore, CVP is increased by eitheranincrease in venous bloodvolume or by a

decrease in venous compliance. However, venous compliance is usually noted by the

diameter of large vein such as vena cava. According to this theory, my current study

investlgated the correlations between cardiovascular pressure and the alteration or

dimensions and dynamic of CVC and HV in daily cows during reproductive cycle.

In the present study, 1t Was revealed that the intravascular pressure of abdominal and

tboracic CVC is increased. Simultaneously the abdominal CVC and HV dilated and the

pulsation index of tboracic are also increased during dry period. Such phenomenons are

not only due to the increasedabdominal pressure and or functional obstruction of venous

retum by compression of the gravid utems but also due to the augment of total blood

volume in pregnancy (46,67)･Because venous compliance and venous capacity are not

static, but dynamic, factors many influences these two variables, such as the total body

86

water and circulatory blood volume (40, 45 and 55), systemic and hepatic circulatory

status (13) as well as abdominal and thoracic pressure (65)･ Therefわre the abdominal

CVC response to the alteration of intravascular pressure is to increase its storage

capacity by the dilatation in its dimension･ Simultaneously the HV, its blood directly

丘11ing lntO the abdominal CVC was also dilated･ On the contrary, the response or the

thoracic CVC in this pressural alteration appeared to decrease in its average diameter and

increased in its pulsation index･ This phenomenon was considered as two kinds of

pressures acting in the wall of thoracic CVC, one of which were the elevated

intravascular pressure from venous filling by the increased total blood volume and the

venous obstmction; the other pressure was the extravascular pressure丘om the elevated

thoracic pressure by the gravid utems compression the diaphragm･ These two kinds of

pressures lead the pulsation of thoracic CVC in heartbeat to become slgnificantly

stronger during dry period. On the other hand, it was un-1gnOrable fact that the thoracic

CVC was a compliant vessel which may seⅣes as a compensation mechanism to

regulate the丘11ing pressure and cardiac preload by its decreased diameter･

A氏er delivery, the mean pressure of abdominaland thoracic CVC was reduced as a

result of the decreased intra-abdominal pressure in replacement by the deflated uterus,

as well as the reduced blood volume and total body water in blood loss during delivery

and postpartumdiuresis (68).At the same times, the dimension of the abdominal CVC

decreased and the diameter of the thoracic CVC increased because of their compliant

mechanism to maintain the venous returnand therefore the right heart filling pressure.

During lactallng period, it is well recognized that the blood volume and cardiac

output of cows is increased (32, 73), simultaneously the distribution of blood volume

87

which flow into mammary glands for milk secretion was increased･ However, there is

no functional obstruction for venous returnby the compress of enlarged uterus in the

reglOn Of CVC･ But, there were fluctuations in the mean pressure of abdominal CVC

followlng the alteration of the daily milk yield per month, while there were slgnificant

positive correlations detected between the meanpressure of abdominal CVC and the

daily milk yield per month･ Similarly, there were slgnificant alterations in HVflow

velocity secondary to the alterations of milk secretion during lactatlng period, as well

as slgnificant positive correlations appeared between the hepaticflow veloclty and the

daily milk yield per month. Such observations were made by Harrison R･0･ et al･ (29)

in his study, except fわr increase of the blood volume and cardiac o山put, there is a

close correlation between dry matter intake and milk production in lactating dairy

cows. One feature of the high-producing lactating dairy cow is high dry matter intake.

However, the increased feed intake elevates liver bloodflow in lactating dairy cows

(80).Therefore, it was considered that the increased dry matter intake was the other

reason why the flow velocity curves of HV corresponding to the curve of milk yield

and both correlated each other statistically significant.

Tbe linear regression analysis perf♭med between related data depends on the

alterations of CVP and the CVC dimensions and dynamics differently responded for this

alteration during the reproductive cycle of dairy cows. The results revealed that the

dimensions of the abdominal CVC and the pulsation index of thoracic CVC positively

correlated with both the mean pressure of the abdominal and thoracic CVC. However,

the average diameter of the thoracic CVC reversely correlated with the mean pressure of

abdominal CVC･ In addition, the mean pressure of the right atrium was not directly but

88

indirectly correlated with the mean abdominal pressure via compensative service of the

thoracic CVC.

Even though there were slgniflCant alterations in the intravascular pressure,

dimensions and dynamics of CVC during reproductive cycle, I noticed that the

fluoroscopic ratio of CVC diameter to the aorta diameter and the length of thoracic

vertebra were flXed value, and the ultrasonographic cross sectional shape of CVC were

always maintained the triangle shape･

Many literatures described that the measurement of the dimensions and dynamics of

the vena cava were widely used for the evaluations of the circulatory dysfunctions･ In

human medicine, both the diameter and collapsibility index of the IVC were applied to

diagnosis of patie山with cardiac disease classically associated with right sided

congestive heart failure (27, 34), tricuspid incompetence (71, 96), pericardial effusion

(20,71), assess of right heart function (78)･ In small animal clinic, dilatation of CVC is

o氏en listed as an indicator of right sided congestive heart failure (47) and applied to the

diagnosis of dogs with heartwormdisease (51), pericardial disease (47), pulmonic

stenosis (53),tricuspid valve regurgitation and dilated cardiomyopathy (60).In cattle,

however, Just a few papers described the dilatation of CVC in with thrombosis of the

CVC or poisoning (13, 61).In the present study, based on the clari丘cation of coⅢ･elations

betⅥ√een the CVP and the dimensions or dynamics of the abdominal and thoracic CVC, I

performed thefluoroscopIC and ultrasonographic examinations in twenty three cows with

circulatory dysfunctions including traumatic pericarditis, septal defect, pericardial

effusion, thoracic effusionand cardiomyopathy to investlgate the usefulness of the

fluoroscopIC and ultrasonographic measurement on dimensions and dynamicsof CVC in

89

dairy cows･ The intra-cardiovascular pressure has been measured in 10 cows totally, and

simply some of the cows indicated increase in the cardiovascular pressure even though

the appearance at necropsy demonstrated that all the cows had circulatory dysfunctions･

The increase in right atrial pressure appeared much earlier than the CVP (including both

abdominal and thoracic CVCpressure) and the jugular vein pressure. The increase in

right atrial pressure may indicate corresponding lnCreaSe in cardiac preloads in cows

with circulatory dysfunction (83). However, thefluoroscopic and ultrasonographic

evaluation revealed that all the cows in test the group, thefluoroscopIC measurement Of

the thoracic CVC were dilated while its pulsation became weaker or even dis叩peared

and the values differed significantly. In addition, the ratios of diameter of CVC to the

diameter of aorta and length of vertebra which always showed as the丘xed value in

healthy dairy cows were slgnificantly increased. Similarly, the ultrasonographic

dimensions of abdominal CVC and HV were dilated while the cross sectional images or

abdominal CVC was altered from the orlglnal triangle to the elliptical or circular shape

in cows with circulatory dysfunctions.

The above results probably due to the situation that when the cardiac preload and

right atrial filling pressure increased in circulatory dysfunction, the vena cava being a

compliant vessel, wbicb is usually compensatory mechanism, prlmarily seⅣes to dilate

its size in order to increase its storage capaclty tO relief the cardiac load. Nevertheless,

when the cardiac preload is in excess of the vena caval compensational capability, the

intravascular pressures begin to increase and remain a high value. These results are in

agreement with previous studies in human and small animal medicine (26, 27, 71, 83

and96).

From this study, I established that there were violent changes in CVP during pre-and

90

postpartum periods due to the increase in the abdominal pressure caused by

compression of the gravid utems and the elevation of blood volume during pregnancy･

In addition, the dimensions and dynamics of the CVC and HV were altered due to the

changes in CVP･ However, the abdominal CVC and thoracic CVC responded differently

to the changes of the CVP･ Both the abdominal and thoracic CVC also seⅣe as an

important compensatory mechanism fわr the alteration of the CVP in order to relief the

cardiac preload. However, its dimensions and dynamics were different in healthy cows

and cow with circulatory dysfunctions. The fluoroscopIC and ultrasonographic

evaluation of CVC and HV, as a non-invasive method provide a useful message for the

diagnosis of circulatory dysfunctions instead of measurlng the CVP.

91

学位論文要旨

氏 名 吉林台

題 目 乳牛の後大静脈における画像診断に関する研究

乳牛は高泌乳を維持しながら分娩,発情回帰,妊娠というサイクルを効率的に繰り

返すことが求められる産業動物であり,循環機能は高泌乳を支える柱である｡循環障害

が発生すると心拍出量が低下して乳量減少の一因となり,乳牛としての能力が十分に発

揮されなくなる｡心疾患をはじめとする循環障害の診断には数多くの診断方法が報告さ

れているが,乳牛の循環障害では慢性に経過することが多く,重篤な臨床症状を呈して

初めて確定診断に至る場合が多いことから,畜主の経済的損失を大きくしているのが現

状であり,早期診断法の確立が必要と考えられる｡

右心不全の診断基準の一つとして,ヒトやイヌでは画像診断における下大静脈(徳

大静脈)の拡張所見が挙げられているが,乳牛の循環障害については創傷性心膜炎､症

賓性心内膜炎,拡張型心筋症などの超音波診断所見が報告されているものの,後大静脈

の拡張所見については後大静脈血栓症に関する報告のみであり,右心不全を含めた循環

障害における後大静脈の画像診断に関する報告は見当たらない｡本研究ではⅩ線検査,

超音波検査およびカテーテルを用いた内圧測定によって,健康乳牛の胸腹部後大静脈の

大きさと内圧,右心房と右心室の内圧,および肝内静脈の直径と流速を測定し,それら

の血行動態と画像所見の関連について明らかにするとともに,右心不全の確定診断が得

られた乳牛の臨床例に対して同様の画像診断および血管内圧測定を実施し,乳牛におけ

る循環障害を画像診断によって早期に診断することが可能か否かについて検討した｡

(第1章)

第2章では,乾乳期および分娩直後の成乳牛を除く健康乳牛の胸部後大静脈のⅩ線

92

透視像について各種Ⅹ線パラメーターを設定して基準値を作成するとともに,これら各

種X線パラメーターの基準値が心疾患例の診断基準として応用可能か否かについて検

討した｡供試牛は健康牛81頭とJL疾患牛10頭であり, Ⅹ線透視検査により胸部後大静

脈の拍動が1番強い部分の最大直径ならびに最小直径(cvcmax & CVCmin),後大静脈の

拍動部位と同一肋間に観察される大動脈直径(Ao)と第8胸椎椎体前後長(VL)を測定

した｡これらのデータから後大静脈の平均径(cVCave- (CVCmax+CVCmin) /2)と拍動率

(cvcp. i. - (CVCmax-CVCmin)/ CVCmax) , CVCaveのAoおよびVLに対する比(CVCave/Ao

およびCVCave/VL)をそれぞれ算出し,分析ソフトSPSSを用いて独立したサンプルのT

検定とPearson相関係数有意差検定を行った｡健康乳牛については36カ月齢で育成牛

と成牛の2群に分けて検討した結果, CVCaveがAoおよびVLなど体格に関するⅩ線パ

ラメーターと有意な相関関係を示した｡ CVCaveとCVCp. i.については2群間でそれぞれ

有意差が認められたもののCVCave/AoおよびCVCave/VLの各比率は体格に関係せず一定

の値(cvCave/Ao: 0.61±0. 10; CVCave/VL: 0.41土0.06)を取ることが明らかとなった｡心

疾患牛では, CVCp. i.は健康牛に比較して有意に減弱し, CVCの拡張に伴ってCVCave/Ao

とCVCave/VLは健康牛に比較して有意に高値を示した｡これらの結果から,健康乳牛に

おけるCVCaveは体格と正の相関関係を有し, CVCave/Aoやcvcave/vLは一定であるこ

とが明らかとなった.また,心疾患牛では健康牛に比較して後大静脈の拡張による明ら

かな拍動の減弱と体格に対する比率の増加が認められた｡しかし,本章に供試した乳牛

は乾乳期および分娩直後の成乳牛を除く健康乳牛であり,妊娠,分娩,泌乳を繰り返す

乳牛では乾乳期,分娩前後,各泌乳期で血行動態が大きく変化することが推察され,こ

れらの時期の牛群についても明らかにする必要があると考えられた｡

第3章では,健康乳牛における妊娠と分娩による腹腔内圧や体液量の変化および泌

乳に伴う循環血液量の変化によって胸部後大静脈の画像所見がどのような変動を示す

かについて明らかにすることを目的とした｡供試牛には搾乳牛22頭を用い,乾乳初期

93

と,分娩後4週目, 10週目, 15週目, 25週目, 35週目および42週目の各時期に,第

2章に述べた方法と同一の方法でⅩ線透視検査を行い,各種Ⅹ線パラメーターについて

計測した｡相関関係と有意差の検定は分析ソフト(SAS System forWindows)を用いて,

corrプロシジャとMIXEDモデルにより行い, p<0.05を持って有意差有りとして評価

した｡その結果, CVCaveは妊娠,分娩,泌乳の各時期に多少の変動はあるものの,有

意な差異は認められなかった｡同時に, CVCave/Ao(0.65士0.12)およびCVCave/VL

(o.45土0.08)の各比率は妊娠,分娩,乳量に関係せず一定の値を示した｡しかし, CVCp.i.

は分娩後4週目には乾乳期に比較して有意に低値を示したが,乳量の増加に伴って分娩

後10週目から徐々に増加し, 15週目にはピークを示した｡その後, CVCp.i.は乳量の

減少に伴って分娩後25週目には減少したが,一部の牛が妊娠した35週目には乳量の

減少には影響されず増加し,さらに多くの牛が妊娠した40週目まで高値を維持した｡

これらの結果から, Ⅹ線透視検査で観察される健康乳牛の胸部後大静脈の拍動率は,妊

娠に伴う腹腔内圧の増大と分娩に伴う腹腔内圧の急激な減少に強く影響され,さらに泌

乳量の増減にも影響されていることが示唆された｡

第4章では,乳牛に対してⅩ線透視検査を実施するためには特別な大型Ⅹ線透視装

置が必要となることから,汎用性が高く牛舎内でも応用可能な超音波装置を用いた超音

波検査によって腹部後大静脈および肝内静脈の画像所見と血行動態の関連について検

討した｡供試牛は第3章で用いた22頭であり, Ⅹ線透視検査を実施した同日に枠場内

起立保定下に3.5MHzコンペックス型探触子を用いて超音波検査を実施した｡超音波検

査では右側第12-13肋骨聞から,吸気時の断層像において通常三角形として観察され

る腹部後大静脈の長径(CVCmax)と短径(CVCmin),さらに腹壁下の肝臓表面から腹部

後大静脈までの深さ(CVCdeptb)を測定した｡さらに,肝内静脈直径を測定するとと

もに,パルスドップラー法により肝内静脈の流速についても測定したo有意差の検定は

第三章と同様の方法で行った｡その結果,腹部後大静脈の断面積および肝内静脈直径は,

94

それぞれ乾乳期には分娩後4週目と比較して明らかに拡張し,有意差を示した｡さらに

腹部後大静脈の断面積および肝内静脈直径はそれぞれ分娩後4週目から40週目にかけ

ては多少の変動は認められたものの有意差は認められなかった｡肝内静脈流速は乾乳期

から分娩後4週目にかけて明らかに増大し,有意差を示した｡分娩後4週目から10週

目にかけて肝内静脈流速はさらに増大する傾向を示し,分娩後10週目以降には徐々に

遅くなる傾向を示したが,いずれも有意差は認められなかった｡肝内静脈直径と実験日

に対応する月の平均日乳量は有意に負の相関関係を示し,肝内静脈流速と実験日に対応

する月の平均日乳量は有意な正の相関関係を示した｡これらの結果から超音波検査で観

察される健康乳牛の腹部後大静脈の断面積と肝内静脈直径および肝内静脈流速は,妊娠

による循環血液量の増加や腹腔内圧の上昇あるいは分娩に伴う循環血液量と腹腔内圧

の著しい減少に関連し,さらに肝内静脈直径および流速は泌乳による循環血液量の変化

にも関連していると考えられた｡

第5章では,周産期における胸腹部後大静脈内圧,右心房･右心室内圧および頚静

脈内圧の変動を明らかにし,これらの変動が後大静脈のⅩ線透視所見ならびに超音波所

見とどのように関連しているかについて検討することを目的とした｡供試牛は前章で用

いた22頭の乳牛のうち7頭であり,同じ実験日に起立状態で頚静脈からカテーテルを

挿入し,右心房の高さを基準として腹部後大静脈,胸部後大静脈,右･L房･右心室およ

び頚静脈それぞれの内圧を測定したoその結果,腹部後大静脈内圧が胸部後大静脈内圧

より有意に高値を示し,胸部後大静脈内圧と右心房内圧はほぼ同じで,右心室内圧は右

心房,胸部後大静脈および腹部後大静脈より有意に高値を示した｡胸部後大静脈内圧は

腹部後大静脈内圧と右心房内圧それぞれに対して正の相関関係を示したが,腹部後大静

脈内圧と右心房内圧の相関関係は認められなかった｡しかし､右心房内圧と頚静脈内圧

は正の相関関係を示した｡さらに第3章ならびに第4章で示した胸部後大静脈の平均径､

拍動率および腹部後大静脈の断面積と後大静脈内圧との関係について検討した結果,腹

95

部後大静脈内圧は腹部後大静脈の断面積ならびに胸部後大静脈拍動率と正の相関関係

を示し,胸部後大静脈平均径と負の相関関係を示した｡さらに胸部後大静脈内圧は腹部

後大静脈断面積および胸部後大静脈拍動率とそれぞれ正の相関関係を示した｡これらの

結果から,右心房内圧と腹部後大静脈内圧が直接関連しているのではなく,胸部後大静

脈を介して関連していることが明らかとなり,後大静脈の大きさや拍動率は後大静脈内

圧の変動と関連し,これら後大静脈の大きさと拍動率の変化は代償的な働きであると考

えられた｡

第6章では,前章までに明らかにした健康乳牛の胸部後大静脈に対するⅩ線透視所

見と腹部後大静脈に対する超音波所見の周産期における動態について,臨床応用可能で

あるか否かについて検討することを目的とした｡臨床例としては,帯広畜産大学畜産学

部附属家畜病院に搬入され,心疾患あるいは循環障害が疑われた乳牛であり,超音波検

査とⅩ線透視検査を行うとともに頚静脈からのカテーテル挿入によって前章で述べた

各部位の血管内圧測定を行い,健康牛の各基準値と比較検討した｡その結果,明らかな

循環障害を呈する乳牛においては,超音波検査では腹部後大静脈の拡張と変形(三角形

から楕円形或いは円形),肝内静脈の拡張が認められ, Ⅹ線検査では胸部後大静脈の拡

張と拍動率の低下が認められた｡血管内圧測定では,右心房内圧が上昇している症例は,

右心房内圧とともに後大静脈内圧も上昇している症例よりも多数認められ､最初に右心

房内圧が上昇し,次いで後大静脈内圧が上昇することが示唆された｡これらの結果から,

コンプライアンスを持つ後大静脈が右心前負荷の上昇に伴って代償性に拡張し,増加し

た後大静脈容量が右心に与える負荷を緩和していると推察され,右心に与える負荷が後

大静脈の代償能力を超えたときに後大静脈内圧も上昇すると推察された｡

本研究では,乾乳期,分娩直後および各泌乳期における健康乳牛の胸部後大静脈の

Ⅹ線透視所見および腹部後大静脈の超音波所見の変動について明らかにするとともに,

各時期における胸腹部後大静脈,右心房･右心室および頚静脈内圧の動態を明らかにし,

96

後大静脈画像所見の変動が各時期における内圧の変動に関連していることを明らかに

した｡すなわち,分娩前後における腹部後大静脈の大きさと胸部後大静脈の拍動率の著

しい変化は,妊娠子宮の圧迫による腹腔および胸腔内圧の変化と,妊娠,分娩による循

環血液量の変化に関連していることが後大静脈内圧の変化から推察された｡また､泌乳

量との関係が明らかになった肝内静脈の直径と流速,胸部後大静脈の拍動率の変化も泌

乳における循環血液量の変化による事象であると推察された｡さらに健康乳牛の後大静

脈の大きさと拍動率は後大静脈内圧あるいは右心前負荷により変化し,後大静脈は右心

房に与える負荷を緩和するための重要な役割を果たしていると考えられた｡

循環障害の疑われた臨床例に対する同様の検索では､後大静脈の拡張､拍動率の減

弱あるいは消失などのⅩ線透視所見および超音波所見が右心房内圧と後大静脈内圧の

上昇より早期に認められることを明らかにした｡すなわち, Ⅹ線透視検査法と超音波検

査法は乳牛における循環障害を早期に診断できる有効な検査法であり,特に超音波検査

法は簡便で有効な検査法であることを明らかにした｡

97

Acknowledgements

I wish to offer my deep appreciation to those who have glVen me Support and

assistance during the course of my studies.

Dr. Kazurou Miyahara, my advisor, (Professor, Department of Clinical Veterinary

Science, Obihiro University) for his advice in this work and his patience.

Dr. Hisashi Inokuma (Professor,Department of Clinical Veterinary Science, Obihiro

University), for his counsel in this work and his patience.

Dr･ Motoyosi Satoh (Professor,Department of Clinical Veterinary Science, Obihiro

University)for advice in this work and for my life in Obihiro.

Dr. Tadaaki Kudoh (Professor,Department of Clinical Veterinary Science, Gifu

University) for his helpful advice in this work.

Dr･ Hideo Kamomae (Professor,Department of Clinical Veterinary Science, Tokyo

University ofAgricultureand Teclmology) for his guidanceand advice in this work.

Dr･ JunYatsuda, (Professor,Department of Clinical Veterinary Science, Iwate

University) for his guidance and advice in this work.

Professor Mitsuyosi Suzuki (Professor, Department of Animal Production and

Agricultural Economics, Obihiro University) for helpful his advice in the statistical

analyses of this work.

Dr･ Hirosi Ishikawa (Associate Professor, Department of Clinical Veterinary Science,

Obihiro University) for advice in this workand for my life in Obihiro.

Finally I would like to express my appreciation to my wife, Soriya, for her insplration

and to my son, Hoshyotsi, for his understandingand my mother for her support･

98

References

1. Abu-Yousef M.M. (1991). Duplex Doppler sonography of the hepatic vein in

tricuspid regurgitation. Am. J Roentgenol. 156(1): 79183.

2. Adler C., Buttner W.and Veh R. (1983). Relations of the ultrasonic image of the

inferior vena cava and central venous pressure. Aktuelle Gerontol. 13(6): 209-1 3.

3. Alv∬ez G, Sanchez la Fuente ∫.,Lopez ∫.and Gomez A. (1989). Flow changes in

hepatic veins in congestive cardiac insufrlCiency. A study uslng Pulse Doppler US.

Euy: J. Radiol. 9(3):163-6.

4. Ando Y., Yanagiba S. and Asano Y., (1995).The inferior vena cava diameter as a

marker of dry weight in chronic hemodialyzed patients. Artljicia1Organs 19(12):

1237-1242.

5. Appleton C.P., Hatle L.K.and Popp R.L. (1987). Superior vena cava and hepatic

vein Doppler echocardiography in healthy adults. J. A. Coll. Cardio. 10 (5):

1032-1039.

6. Azaria J. J. T. (1982).Echocardiography of the inferior vena cava in healthysubject

and in patient with cardiac disease. IsraelJ. Med. Sci. 18: 581-585.

7. Barbier C, Loubieres Y, Schmit C, Hayon J, Ricome JL, Jardin F.and Ieillard-Baron

A･ (2004)･ Respiratory changes in inferior vena cava diameter are helpful in

predictingfluid responsiveness in ventilated septic patients. Int. Care Med. 30(9):

1740-1746.

8. Baumann U.A., Marquis C., Stoupis C., Willenberg T.A., Takala ∫.and Jakob S.M.,

(2005) Estimation of central venous pressure by ultrasound. Resuscitation 64(2):

193-199.

99

9. Bendjelid K., Romand J･-A., Walder B., Suter P.M･ and Foumier, G･ (2002)･

Correlation between measured inferior vena cava diameter and right atrial pressure

depends on the echocardiographic method used in patients who are mechanically

ventilated. J. Am. Soc. Echocardiogr 15(9):944-949.

10. Bendjelid K. (2005). Right atrial pressure: determinant or result of change in

venous return? Chest. 128(5):3639-3640.

ll. Bolondi L., Li Bassi S., Gaiani S., Zironi G, Benzi G, Santi V and Barbara L.

(1991) Liver cirrhosis: Changes of Doppler wave form of hepatic veins. Radiology

178(2):513-516.

12. Braun U.and Gerber D. (1994). Influence of age, breed,and stage of pregnancy on

hepatic ultrasonographic findings in cows. Am. j. vet. res. 55 (9):1201-1205.

13. Braun U., Linggi T. and Pospischil A. (1999) Ultrasonographic丘ndings in three

cows with chronic ragwort (Senecioalpinus) poisoning. Vet. Rec. 144 (5):1221126.

14. Braun U., Fluckiger M., Feige K. and Pospischil A. (2002). Diagnosis by

ultrasonography of congestion of the CVC secondary to thrombosis in 12 cows. Vet.

Rec. 150(7):209-213.

15. Capomolla S., Febo 0., Caporotondi A., Guazzotti G., Gnemmi M., Rossi A., Pinna

G., Maestri R.and Cobelli F. (2000). Non-invasive estimation of right atrial

pressure by combined Doppler echocardiographic measurements of the inferior

vena cava in patients with congestive heart failure. Ital. Heart J. 1 (10):684190.

16. Catherine C.Y and Pang (2001). Autonomic control of the venous system in health

and disease: effects of drugs. Pharma. Therap. 90 (2-3): 1791230.

17･ Chait H･I･, KulmMA and Baum V･C･ (1994) Inferior vena caval pressure reliably

predicts right atrial pressure in pediatric cardiac surglCal patients. Crit. Care Med.

100

22(2): 219-24.

18. Cheriex E.C., Leunissen K. M. L., Janssen J. H. A., Mooy J.M.V., and van HooffJ.P.

(1989). Echography of the inferior vena cava is a simple and reliable tool for

estimation of ､dry weight､ in haemodialysIS Patient, Nephrol. Dial. Transplant･

4:563-568.

19. Christopher F., Ciliberto, Gertie F. and Marx (1998). Physiological changes

associated with pregnancy. WorldAnaesth. 9 (2):1-3.

20. Curvo-Semedo L., Teixeira L. and CaseiroIAIves F. (2005). Tuberculosis of the

chest. Eur. J. Radiol. 55: 1581172.

21. de Laforcade A.M. and Rozanski E.A.(2001).Central venous pressure and arterial

blood pressure measurements. Vet. Clin. North Am. Small. Anim. Pract. 31(6):

1163-74.

22. Dellinger R.P., Carlet J.M. and Masur H. (2004). Surviving sepsis campaign

guidelines for management of severe sepsISand septic Shock. Crit. Care Med. 32

(3):858-873.

23. Dorje P.and Tremper K.K. (2005).Systolic pressure variation: a dynamic measure

of the adequacy of intravascular volume. Semin. Anesth, Perioperat. Med. Pain.

24(3):147-153.

24. Duvekot J.J., Cheriex E.C., Tan D.V., Heidendal G.A.K. and Peeter L.L.H. (1994).

Measurement of anterior-posterior diameter of inferior vena cava by

ultrasonography: a new noninvasive method to assess acute changes in vascular

filling status; Cardiovas. Res. 28: 1269-1272.

25･ ElkayamU･ and Gleicher N･ (1998) Hemodynamicand cardiac function during

normal pregnancy and the puerperium･ in: Cardiac Problems in Pregnancy:

101

Diagnosis and Management of Maternal and Fetal Heart Disease. Uri Elkayam

and Norbert Cleicher 3rd Ed. published by Wiley-Liss:3-20.

26. Gidlewski J. and Petrie J.-P. (2005). Therapeutic pericardiocentesis in the dog and

cat. Clin. Tech. SmallAnim. Pract. 20 (3): 151-155.

27. Goei R., Ronnen H.R., Kessel Ah. and Kragten J. A. (1997). Right heart failure:

diagnosis via ultrasonography of the inferior vena cava and hepatic veins. Rofo

Fortschr Geb Rontgenstr Neuen Bildgeb Verjbhr 166(1):36-9.

28. Hariri R.J., Firlick A.D. and Shepard S.R., (1993). Traumatic brain injury,

hemorrhagic shock, and fluid resuscitation: effects on intracranial pressure and

brain compliance. J Neurosurg. 79 (3):4211A27.

29. Harrison R. 0., Ford S. P., Young J. W., Conley A. J., and Freeman A. E. (1990).

Increased milk production versus reproductive and energy status of high producing

dairy cows. J. Dairy Sci. 73(10): 2749-2758.

30･ Hasegawa M･ 1980･ Mechanical and physiological aspects of the venous system.

Cardio. 7(2), 110-118.

31･ Henriksson L., Hedman A., Johansson 良. and Lindstrom K. (1982). Ultrasound

assessment of liver veins in congestive heart failure. Acta. Radiol. Diagn. 23(4):

361-3.

32･ Hirose H･ (2002). correlation between milk yield and heart rate in dairy cows. Adv.

Anim. Cardiol. 35(1): 48151.

33･ Ho氏man N･, Braunfeld M., Ho氏man G., Mahajan A. (2006) Peripheral venous

pressure as a predictor of central venous pressure duringor血otoplC liver

transplantation. J Clin.Anesth. 1 8 (4):25 11255.

34･ HollerbachS･, SchultzeK･, Muscholl M. and Sch61merichJ. (2001).

102

ultrasonography of the inferior vena cava (IVC) in the diagnosis and monitoring of

therapy ln Patients with chronic congestive heart failure･ Dtsch･ Med･ Wochenschr･

126:129-133.

35. Hurley W. L. (2004). Mammary Gland Anatomy of Cattle･ Lactation Biology･

36. Isaacson I.JっLowdon ∫.D. and Berry A.∫. (1990). The value of pulmonary artery

and central venous monitorlng in patients undergolng abdominal aortic

reconstructive surgery: a comparative study of two selected, randomized groups･ J･

Vasc. Surg. 12(6):754-760.

37. Ishizaki Y, Bandai Y, Shimomura K., Abe H., Ohtomo Y and. Idezuki Y (1993).

Changes in splanchnic blood flow and cardiovascular effects followlng Peri toneal

insufnation of carbon dioxide. Surg. Endosc. 7: 420-423.

38. Joynt GM., Gomersall C.D., Buckley T.A., Oh T.E., Yわung R･J･, Freebaim R･C･

(1996) Comparison of intrathoracicand intra-abdominal measurements of central

venous pressure. Lancet. 347 (9009):115511157.

39. Jue J., Chung W. and Schiller N.B. (1992). Does inferior vena cava size predict

right atrial pressures in patients recelVlng mechanical ventilation? J. Am. Soc.

Echocardiog7: 5(6):613-9.

40. Katzarski K.S., Nisell ∫.,Randmaa I.,Danielsson A., Freyschuss U. and Bergstrom

J. (1997). A critical evaluation of ultrasound measurement of inferior vena cava

diameter in assesslng dry weight in normotensiveand hypertensive hemodialysIS

patients. Am. J. Kidney 30: 4591A65.

41. Klein H.H. and Pich S. (2003) Cardiovascular changes during pregnancy. Herz. 28

(3):173-174.

42. Korytnikov K.I., Martyniuk A.D. and Pustovit L.K. (1991). Dopplerography of the

103

1arge hepatic veins in the diagnosis of tricuspid valve insuf{1Ciency･ Ter･ Arkh･

63(4):13-7.

43. Korytnikov K.I. (1992). Possibility of the evaluation of right ventricular failure in

ischemic heart disease based on pulse Doppler ultrasonography of large hepatic

veins. Klin. Med. 70(3-4):34-7.

44. Kdhtscher M.V., Germann G. and Hartmann B.(2006) Correlations between cardiac

output, stroke volume, central venous pressure, intra-abdominal pressure and total

circulating blood volume in resuscitation of major burns. Resuscitation 70 (1):37-43.

45. Kusaba T., Yamaguchi and Oda H. (1994). Echography of the inferior vena cava for

estimatlngfluid removal from patients undergolng hemodialysis, Jpn. J. Nephrol.

36(8):914-920.

46. Laureano B.A.,Andrus C.H.and Kaminski D.L. (1998). Cardiovascular changes

during laparoscopy. In: 良.∫.Rosenthal et al., Editors, The patbophysiology of

pneumoperitoneum, Springer, Berlin. 77-84.

47. Lebmkuhl L.B., Bonagura ∫.D., Biller D.S., Hartman W.M., (1997).Radiographic

evaluation ofcaudal vena cava size in dogs. Vet. Radiol. Ultrasound. 38:941100

48. Lin M.-C., Fu Y-C., Jam S.-L., Chen Y-T. and Chi C.-S.(2005).Comparison of

rigbt atrial pressure and central venous pressures measured at various anatomical

locations in children. Acta Paediatrica Taiwanica 46 (2) 82186.

49. Linzell J.L. (1974).Mammary Blood Flow, Methods of identifying and measuring

precursors of milk, Lactation-A Comprehensive Treatise-.,

Larson B L.,

Academic Press, New Yわrk and London. 143-225.

50･ Litmanovitch M･, Hon H･, Luyt D.K･, Dance M･ and Mathivha L.良. (1995).

Comparison of central venous pressure measurements in the intrathoracicand the

104

intra-abdominal vena cava in critically illchildren. Anaesthesia. 50(5): 407-1 0.

51. Litster A., Atkins C., Atwell 良. and Buchanan ∫.(2005).Radiographic cardiac size

in catsand dogs with heartwormdisease compared with reference values uslng the

vertebral heart scale method: 53 cases J. Vet. Cardiol. 7(1):33-40.

52. Lloyd T.良., Donnerstein 良.L., and Berg 良.A. (1992). Accuracy of central venous

pressure measurement from the abdominal inferior vena cava. Pediatrics 89:

506-508.

53･ Lombard C･ W･, Ackerman N･, Berry C. R., King R R. and Buergelt C. D. (1989).

Pulmonic stenosis andright-to-left atrial shunt in three dogs.,J. Am. Vet. Med.

Assoc. 194(1):7115.

54･ L6pez-Herce J･, Rup6rez M., Sanchez C., Garcia C.and Garcia E. (2006).

Haemodynamic response to acute hypovolaemia, rapid blood volume expansion

and adrenaline administration inaninfantanimal model. Resuscitation. 68 (2):

259-265.

55･ Lyon M･, Blaivas M., Brannam L. (2005).Sonographic measurement of the inferior

vena cava as a marker of blood loss. Am. J. Emerg. Med. 23(1):45-50.

56. Mandelbaum A. and Ritz E. (1996). Vena cava diameter measurement for

estimation of dry weight in haemodialysIS Patients･ Nephrol･ Dial･ Transplant･

11(2): 24-7.

57･ Mintz G･B･, Kotler M･N･, Parry W･R･, Iakandrain A.S. and Kane S.A. (1981).

Real-time inferior vena cava ultrasonography: normal and abnormal findings and its

use in assessing right-heart function. Circulation. 64(5): 101 8125.

58･ Minutiello L･ (1993). Non-invasive evaluation of central venous pressure derived

from resplratOry Variations in the diameter of the inferior vena cava. Minerva

105

Cardioangiol. 41(10): 43317.

59･ Minutiello L･ (1994)･ Value of the vena cava index in healthy young subjects.

Echocardiographic study. Minerva Cardioangiologica 42(5):229-232.

60･ Mitten RIW･, Edwards G･A･ and Rislmiw M. (2001). Diagnosis and management of cor

triatriatum dexterina Pyrenean mountain dog and an Akita lnu. Aust Vet Vol. 79 (3):

177-180

61･ Mobamed T･, Sato H･, Kurosawa T･ and Oikawa S. (2004). Ultrasonographic

localization of thrombi in the caudal vena cava and hepatic veins in a heifer･ Vet. J

168(1): 103-106.

62･ MohⅡnan D･E･ and Heller L.∫. (2002) Central venous pressure: an indicator of

circulatory status･ In: Cardiovascular physiology 5th Ed･ McGraw-Hill/Appleton

and Lange: 146-157.

63･ Moore P･J･ (1994)･ Matemal physiology during pregnancy. Alan H. Decberney, and

Martin L･ Pemoll Obstetric and GynecologlC Diagnosis and Treatment.

McGraw-Hill Medical Publishing Division. 8th Ed. (1994/06): 146-54.

64･ Nahum E･, Dagan O･, Sulkes J and Schoenfeld T. (1996). A comparison between

continuous central venous pressure measurement from right atrium and abdominal

vena cava or common iliac vein. Intensive Care Med. 22(6): 57114.

65･ Natori H･, Tamaki S･ and Kira S･ (1979)･ Ultrasonographic evaluation ofventilatory

effect on inferior vena cava configuration･ Am･ Rev･ Respirat･ Dis･ 120: 421-427.

66･ Payne E･, Ryley J.W. and Gartner R.J. (1967) Plasma, blood and extracellularfluid

volumes in grazing Here ford cattle. Res. Vet. Sci. 8(1):20-26

67･ Piscaglia F･, Zironi G and Gaiani S. (1997). Relationship between splanchnic,

peripheral and cardiac haemodynamics in liver cirrhosis of different degrees of

severlty･ Euy: J. Gastroenterol. Hepatol. 9: 799-804.

106

68･ Pritchard J･A･ (1965): Changes in blood volume during pregnancy and the

puerperium･ Anesthesiology. 26: 393.

69･ Qublan H･ S･, Malkawi H.Y., Smadi A.Z. and Fraywan N. (2005). Gastric volvulus

caused by paraesophageal hemia complicatlng mid-trimester pregnancy･ Indian J･

Chest Dis. Allied. Sci. 47: 285-287.

70･ Reedy M･B･, Galan H･L･, Bean-Lijewski J.D., Carnes A., Knight A.B. and Kuehl T.J.

(1995)･ Maternaland fetal affects of laparoscopic insufnations in the gravid baboon.

J･ Am･ Assoc･ Gynecol. Laparoscop. 2(4):3991406.

71･ Rein A･J･, Lewis N･and Forst L. (1982). Echocardiography of the inferior vena

cava in healthysubjectsand in patients with cardiac disease. Israel J. Med. Sci.

18(5): 58ト585.

72･ Resnik R･ (1994)･ The puerperium･ In: Maternal, fetal medicine principles and

practice saunders･ Creasy R･ K･and Resnik R･ Edit･ Philadelphia, PA: 142-143.

73･ Reynolds M･ (1953)･ Measurement of bovine plasma and blood volume during

pregnancy and lactation. J. Am. physiolo. 175: 1 18-122.

74･ Richardson D･J･ and Tri比le K･J･ (1976)･ Hemodynamic and respiratory alterations

with increased intra-abdominal pressure. J. Surg. Res. 20 (5):4011404.

75･ Rivers E･, Nguyen B･ and Havstad S･ (2001)･ Early goal-directed therapy in the

treatment of severe sepsis and septic shock. N. Engl. J Med. 345 (19): 1368-1377.

76･ Robson S･C･, Hunter S･, Moore M･ and Dunlop W･ (1987)･ Haemodynamicchanges

during the puerperium: a Doppler and M-mode echocardiographic study･ Br J

Obstet. Gynaecol. 94: 1028-1039.

77･ Roobottom C･A･, Hunter J･D･, Weston M･J･ and Dubbins P.A. (1995). Hepatic

venous Doppler wave forms: Changes in pregnancy. J. Clin. Ultras. 23(8): 477-482.

107

78. Ryo E., Unno N., Hagino D., Kozuma S., Nagasaka T･ (1999)･ Taketani Y･ Inferior

vena cava diameter and the risk of pregnancy-induced hypertension and fetal

compromise. Int. J.Gynecol. Obstet. 65(2): 143-148･

79. Ryo E., Urmo N., Nagasaka T.and Taketani, Y. (2004).Changes in the size of

matemal inferior vena cava during pregnancy. J. Perinat. Med. 32(4): 327-33 1.

80. Sangsritavong S., Combs D. K., Sartori R., Armentano L. E. and Wiltbank M. C･

(2002).High feed intake increases liver bloodflowand metabolism of progesterone

and estradiol117L3 in dairy cattle. J. Dairy Sci. 85:283 1-2842.

81. ShailjaS., Gupta I.and Suri V. (2004).Inferior vena cava diameters in pregnant

women for prediction of pregnancy-induced hypertension. Int. J. Gynecol. Obstet.

84(2):164-165.

82. Shapiro R.S., Winsberg F., Maldjian C., Stancato-Pasik A. (1993). Variability of

hepatic vein Doppler tracings in normal subjects.J. Ultras. Med. 12(12):701-703.

83. Simizu T., lnaba Y., Onuma M., Kanagawa H., Fujinaga T., Ilonyosi S. (1988) Buitrics

Second Edition. KindaiPublisher.4321450.

84. Simonson ∫.S. and Schiller N.B. (1988). Sonospirometry: a new method fわr

noninvasive estimation of mean right a土rial pressure based on two-dimensional

echographic measurements of the inferior vena cava during measured insplration. J.

Am. Coll. Cardiol. ll(3):557-564.

85. Siu S. C. and ColmanJ. M, (2001). Heart disease and pregnancy. Heart.

85:710-715.

86･ Stevenson L･W･ and PerloffJ･K. (1989)･The limited reliability ofphysical signs for

estimating hemodynamics in chronic heart failure, J･ Am. Med. Asso. 261(6):

884-888.

108

87. Stevenson L.W. Tillisch ∫.H. and Hamilton M. (1990). Importance ofhemodynamic

response to therapy ln Predicting survival with ejectionfraction less than or equal to

20% secondary to ischemic or nonischemic dilated cardiomyopathy. Am. J･ Cardiol･

66(19): 1348-1354.

88. Suter P.F. and Lord P.F. (1971). A critical evaluation of the radiographic findings in

canine cardiovascular diseases. J Am. Vet. Med. Assoc. 158: 358-71.

89. Suzuki K., Hirose H., Hokao R., Takemura N. and Motoyosi S., (1993). Changes of

plasma osmotic pressure during lactation in rat. J. Vet. Med. Sci. 55: 561-564.

90. Tamaki S. (1981) Relationship between ventilatory change of the inferior vena cava

and central venous pressure. Nihon Kyobu Shikkan Gakkai Zasshi. 19(7):46019. (In

Japanese).

91. The Holstein Cattle Association of Japan. (HCAJ,1995). Standard grows value of

Holstein dairy cattle. (InJapanese).

92. Thornburg K.L., Jacobson S.1L., Giraud G.D. and Morton, M.J. (2000).

Hemodynamic changes in pregnancy. Semin. Perinatol. 24(1): 1 1-14.

93. Tuman K.J., McCarthy R.J.,and. Spiess B.D. (1989). Effect of pulmonary artery

catheterization on outcome in patients undergolng coronary artery Surgery.

Anesthesiol. 70(2): 199-206.

94･ VanOppen A･ C･, Stigter R. H. and Bruinse H･ W. (1996) Cardiac output in normal

pregnancy: a critical review. Obstet. Gynecol. 87: 3 10-3 18.

95･ VanWinden S･C･, Brattlnga C･R･, Muller K･E･, Noordhuizen J･P･ and Beynen

A･C･(2002) Position of the abomasum in dairy cows during the first six weeks after

calving. Vet. Rec. 151(15): 446-9.

96･ Vaturi M･, Shapira Y., Vaknin-Assa H., Oron A., Matesko R. and Sagie A. (2003).

109

Echocardiographic markers of severe tricuspid regurgltation associated with

right-sided congestive heart failure. J. Heart Valve Dis. 12 (2):1971201.

97･ Wachsberg R･H･, Levine C･D･, Maldjian P.D. and Simmons M.Z. (1998). Dilatation

of the inferior vena cava in patients with cirrhotic portal hypertension･ Causes and

imag･ jindingsClini. Imag.. 22(1): 48-55.

98･ Walsh J･T･, Hildick-Smith D.J.R., Newell S.A., Lowe M.D., Satchithananda D.K.

and Shapiro, L.M. (2000). Comparison of central venous and inferior vena caval

pressures. Am. J. Cardiol. 85 (4):518-520.

99･ Wittek T･, Constable P･D･ and Morin D.E. (2005). Ultrasonographic assessment of

change in abomasal position during the last three months of gestation and first three

months of lactation in Holstein-Friesian cows･ J Am. Vet. Med. Assoc. 227(9):

1469-75.

100･Woodford S･T･, Murphy M･R･, Davis C･L･ (1984) Water dynamics of dairy cattle as

affected by initiation of lactation and feed intake. J. dairy sci. 67(10)233612343.

110