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Hemodynamic Monitoring 2016Avoiding Occult hypoperfusion

Tom Ahrens, PhD RN FAAN

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NO! Physical Assessment is often inaccurate, slow to change and difficult to interpret 4

• Stroke volume falls• Heart rate compensates to keep cardiac output

normal– Many reasons for heart rate to increase

• Cardiac output falls• Heart rate compensation fails• Vasoconstriction (increase in SVR), BP remains

unchanged• Increased oxygen extraction of hemoglobin

• Peripheral initially (StO2)• Central later (ScvO2)

• Blood pressure, urine output change5

Signs of Hypoperfusion

LV dysfunction

Hypovolemia

Sepsis

Which signs are similar with all

three?

BP

HR

LOC

Urine output

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• Connors AF Jr, Dawson NV, Shaw PK, Montenegro HD, Nara AR, Martin L. Hemodynamic status in critically ill patients with and without acute heart disease. Chest. 1990 Nov;98(5):1200-6.

• Dawson NV, Connors AF Jr, Speroff T, Kemka A, Shaw P, Arkes HR. Hemodynamic assessment in managing the critically ill: is physician confidence warranted? Med Decis Making. 1993 Jul-Sep;13(3):258-66.

• Eisenberg PR, Jaffe AS, Schuster DP. Clinical evaluation compared to pulmonary artery catheterization in the hemodynamic assessment of critically ill patients. Crit Care Med. 1984 Jul;12(7):549-53.

• Iregui MG, Prentice D, Sherman G, Schallom L, Sona C, Kollef MH. Physicians' estimates of cardiac index and intravascular volume based on clinical assessment versus transesophageal Doppler measurements obtained by critical care nurses. Am J Crit Care. 2003 Jul;12(4):336-42.

• Neath SX, Lazio L, Guss DA. Utility of impedance cardiography to improve physician estimation of hemodynamic parameters in the emergency department. Congest Heart Fail. 2005 Jan-Feb;11(1):17-20.

• Staudinger T, Locker GJ, Laczika K, et al. Diagnostic validity of pulmonary artery catheterization for residents at an intensive care unit. J Trauma. 1998 May;44(5):902-6.

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• CVP and PAOP should never be used in isolation–Inconsistent in revealing information about

volume and flow• Flow and pressure do not always correlate

–Marik et al. Based on the results of our systematic review, we believe that CVP should no longer be routinely measured in the ICU, operating room, or emergency department.

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Marik P, Baram M, Vahid B. Does central venous pressure predict fluid responsiveness?A Systematic Review ofthe Literature and the Tale of Seven Mares. Chest 2008;134;172-178

Trends…..Trends…..BaselineBaseline

SV 22SV 22

HR 113HR 113

CO 2.5CO 2.5

FTc 288FTc 288

CVP 7CVP 7

S/P 5000 S/P 5000 mlsmls

7575

83 83

6.5 6.5

360 360

7 7

S/p 250 S/p 250 mlsmls LR LR

3333

99 99

3.2 3.2

310 310

7 7

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• Is BP is measured because it can be measured

• If BP increases, does blood flow increase?– think of use of levophed

• Blalock 1943, says:“It is well known by those interested in this “It is well known by those interested in this “It is well known by those interested in this “It is well known by those interested in this subject that the blood volume and cardiac subject that the blood volume and cardiac subject that the blood volume and cardiac subject that the blood volume and cardiac output are usually diminished in traumatic output are usually diminished in traumatic output are usually diminished in traumatic output are usually diminished in traumatic shock before the arterial blood pressure shock before the arterial blood pressure shock before the arterial blood pressure shock before the arterial blood pressure declines significantly”declines significantly”declines significantly”declines significantly”

Blalock A, (1943) Surgery 14: 487-508

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BP Measurement - Useful or Misleading?BP Measurement - Useful or Misleading?

Do they equal each other?

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• CO = Stroke volume x heart rate–decrease in SV causes increase in heart

rate–decrease in CO causes increase in SVR

• Compensatory changes keep the BP close to normal initially in shock states

• BP does not change until late due to these compensatory responses

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What is the Purpose of Blood Pressure?The role of the biventricular cardiovascular system

What is the Purpose of Blood Pressure?The role of the biventricular cardiovascular system

Systemic Values Pulmonic Values

LV 110/10 RV 25/0-5

Aorta 120/80 PA 25/10

Capillaries 30-50 Capillaries 12-17

RA 0-5 LA 8-12

Stroke Volume as an End point

Stroke volume normal valuesStroke volume variation

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• Chytra I, Pradl R, Bosman R, Pelnar P, Kasal, Zidkova A. Esophageal Doppler-guided fluid management decreases blood lactate levels in multiple-trauma patients: a randomized controlled trial. Critical Care 2007 Feb 22;11(1):1-9.

• Conway DH, Mayall R, Abdul-Latif MS, Gilligan S, Tackaberry C. Randomized controlled trial investigating the influence of intravenous fluid titration using esophageal Doppler monitoring during bowel surgery. Anesthesia 2002 Sept;57(9):845-849.

• Gan TJ, Soppitt A, Maroof M, El-Moalem H, Robertson K, Moretti E, Dwane P, Glass PS. Goal-directed intra-operative fluid administration reduces length of hospital stay after major surgery. Anesthesiology 2002;97:820-826.

• Mark JB, Steinbrook RA, Gugino LD, et al. Continuous noninvasive monitoring of cardiac output with esophageal Doppler during cardiac surgery. Anesth Anlg 1986;61:1013-1020.

• McKendry M, McGloin H, Saberi D, Caudwell L, Brady AR, Singer M. Randomized controlled trial assessing the impact of a nurse delivered, flow monitored protocol for optimization of circulatory status after cardiac surgery. BMJ 2004;329(7460):258 (31 July), doi:10.1136/bmj.38156.767118.7C.

• Mythen MG, Webb AR. Peri-operative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery. Archives of Surgery 1995;130:423-429.

• Sinclair S, James S, Singer M. Intraoperative intravascular volume optimization and length of hospital stay after repair of proximal femoral fracture: randomized controlled trial. BMJ 1997 October 11;315:909-912.

• Valtier B, Cholley BP, Belot JP, Coussay JE, Mateo J, Payen DM. Noninvasive monitoring of cardiac output in critically ill patients using transesophageal Doppler. Am J Respir Crit Care Med. 1998;158:77-83.

• Venn R, Steele A, Richardson P, Poloniecki J, Grounds M, Newman P. Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures. British Journal of Anesthesia 2002;88:65-71.

• Wakeling HG, McFall MR, Jenkins CS, Woods WGA, Miles WFA, Barclay GR, Fleming SC. Intraoperative esophageal Doppler guided fluid management shortens postoperative hospital stay after major bowel surgery. Br J Anaesth. 2005 Nov;95(5):634-42. 15

Evidence (8 RCTs) of Using SV as Evidence (8 RCTs) of Using SV as Evidence (8 RCTs) of Using SV as Evidence (8 RCTs) of Using SV as EndpointEndpointEndpointEndpoint

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SV Optimization for Fluid SV Optimization for Fluid SV Optimization for Fluid SV Optimization for Fluid AdministrationAdministrationAdministrationAdministration

Stop giving fluids Monitor SI as indicated

Give 200 ml of colloid Or 500 ml of crystalloid

If SV/SI or FTc is low

Is the heart Pumping enough

Blood?

YES(SI increased < 10%)

NO(SI increased > 10%)

If SV/SI decreased >10%

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Stop treatment Monitor SI as indicated

Give preload reducer, afterload reducer or inotrope

If SV/SI or PV is low

Is the heart Pumping enough

Blood?

YES(SI increased < 10%)

NO(SI increased > 10%)

If SV/SI decreased >10%

SV Optimization for Ht Failure SV Optimization for Ht Failure SV Optimization for Ht Failure SV Optimization for Ht Failure

SV as an End point

SV normal values

SV variation

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Moving Toward Blood Flow Moving Toward Blood Flow Moving Toward Blood Flow Moving Toward Blood Flow MeasurementMeasurementMeasurementMeasurement

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Determine success of fluid or inotropic therapy by The response in stroke volume/index and SvO2

Stroke Volume

End-Diastolic Volume

∆∆∆∆ < 10%

∆∆∆∆ > 10%

∆∆∆∆ 0%

Treatment Guidelines

Uses Ease of use Accuracy Professional Reimbursement

Doppler -USCOM

Anywhere Good Good -

Doppler (EDM) OR, ICU Excellent Excellent $$$

ECON OR, ICU Good Fair -

Bioimpedance Anywhere Good Fair $

Pulse contour(FloTrac, LiddCo, PICCO)

OR, ICU Difficult Fair -

NICO OR, ICU Difficult Fair -

PAC OR, ICU Difficult Good $$

Bioreactance OR, ICU Good Good $ 20

Methods of Measuring SVMethods of Measuring SVMethods of Measuring SVMethods of Measuring SV

Non invasive CO/SV measurement

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• All methods have strengths and limitations

• Many acute and critical care patients can have these techniques used

• All can be used within limitations

• Use oxygenation end points to validate information regarding blood flow

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Arguable – but the one with the most evidence is clear – esophageal Doppler

Which has the most potential application?Non invasive Doppler

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Which Technique is Best?Which Technique is Best?Which Technique is Best?Which Technique is Best?

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U.S. & U.K. Support at the U.S. & U.K. Support at the U.S. & U.K. Support at the U.S. & U.K. Support at the Federal LevelFederal LevelFederal LevelFederal Level

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Example of a real screenExample of a real screenExample of a real screenExample of a real screen

Stroke Volume Optimization is the Key

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Overview

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Interpreting Stroke VolumeInterpreting Stroke VolumeInterpreting Stroke VolumeInterpreting Stroke Volume

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• SV: How much blood is pumped with each beatNormal: 50-120 ml/beat

• SI: How much referenced against body sizeNormal: 25-50 ml/m2

• SD: The distance that blood flows in a specifictime period (This is the most accurate).

Normal: > 10; Hypovolemia: <10

*Normals are just reference points. The real test is whether or not they change if fluid is given.

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FTc: Flow Time correctedThe time of systolic flow corrected to heart rate.

PV: Peak VelocityThe velocity of the blood measured at the peak of systole.

20 yrs: 90 - 120 cm/sec50 yrs: 60 - 90 cm/sec70 yrs: 50 - 80 cm/sec

330 - 360 milliseconds

Normal Ranges

NOTE: Normal Ranges should not be confused with a Physiological Target.

Esophageal Doppler Variables

• After induction, FTc of 323ms, (low) indicated possible hypovolemia.

• SV of 77 ml was reasonable; however, HR of 60 gives a cardiac index (CI) of 2.3 l/m/m2.

• 200ml of colloid was given.

• SV increased >10%, suggesting more colloids be given to optimize the intravascular volume.

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• After 2nd bolus, SV increased by 14 ml (19%) and FTc also increased.

• CI increased from 2.3 to 2.7 l/min/m2

• Indicated more fluid could be given to optimize SV.

• More colloid given in accordance with the SV optimization algorithm until SV increases were less than 10%.

Who is being harmed by our current practices?

We must have a sense of urgency32

Seeking a Direct Measure of Tissue Oxygenation

• Blood draw

• Lab or bedside analysis

• Normal lactate – 1-2 mmol

• pH – normal 7.35-7.45

• If lactate > 4 mmol and pH is less than 7.30, consider tissue hypoxia

• CAUTION: Lactate can increase for reasons other than hypoxia

• Reflects perfusion status where oxygen is delivered to tissue

• If StO2 is < 75% or dropping, consider inadequate tissue perfusion

• Potentially earliest indicator of a threat to tissue oxygenation

• CAUTION: May not be the same as ScvO2 or SvO2

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Lactate as Indicator of Hypoxia

Chemical energy(high-energyElectrons)

GLYCOLYSIS

Glucose Pyruvicacid

Chemical Energy

KREBSCYCLE

Electron transport chain and oxidativephosphorylation

Mitochondrion

ATPsATPs

Cristae

ATPs

Lactate N= 529

< 2 (N=219) 2-4 (N=177) > 4 (N = 104)

SBP > 90 158/219 (72%)116/177 (65%)

64/104 (62%)

SBP < 9061/219 (28%) 61/177 (34%)

40/104 (38%)

Lactate Levels and SBP

No Ventilation CPR

ABC’s or CAB’s

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The relationship between hemodynamics and oxygenation

The relationship between hemodynamics and oxygenation

The role of mixed venous oxyhemoglobin (SvO2)

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Microvascular Blood Flow Is Impaired with normal or

elevated macro hemodynamics (SV, CO)

Venous blood

Arterial bloodSO2 - .98

SO2 - .94

SO2 - .65

SO2 - .86

SO2 - .65

SO2 - .83

SO2 - .65

StO2 Monitoring

Near Infra-Red Spectrometry (NIRS)

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• Hemodynamic monitoring should focus on stroke volume optimization

• Most patients can have hemodynamic monitoring

• Tissue oxygenation should be combined with macro hemodynamic measurements

• The application of hemodynamic monitoring is greater than ever

Summary