HEMODYNAMICS

Carol Peyton Bryant,RN, MSN, ACNP, CCRNPriority Care, St. Mary’s

Objectives:

• The participant will be able to discuss hemodynamic definitons(cvp,pa,pcwp,co,ci,svr and pvr) and how they relate to the respiratory patient.

• The participant will use critical thinking skills in assessing changes in respiratory status/ventilation with changes in hemodynamic status.

• INDICATIONS FOR HEMODYNAMIC MONITORING– Shock– Pulmonary edema of uncertain etiology– Postcardiac surgery– Cardiac tamponade– Acute respiratory failure– Need to evaluate for fluid status/guideline for fluid

resuscitation– Need to evaluate hemodynamic response to potent

pharmacologic agents– MI

• especially with an acute right or left ventricular failure• Refractory pain• Significant hypotension or hypertension

Blood pressure• Blood pressure=CO X SVR

– Changes in blood pressure are caused by either a change in cardiac output or by systemic vascular resistance

– MAPMean arterial pressure=SBP + (DBP x 2) = 70-105 mm Hg

3– The average blood pressure occurring in the aorta

and its major branches during the cardiac cycle

Stroke volume: CO ÷ HRThe amount of blood ejected by the left ventricle during systole. N= 60-120 ml/beat

Stroke Index: SV ÷ BSAThe SV indexed for differences in body size by dividing by BSA. N= 30-65 ml/m2/beat

Ejection Fraction: % of blood in the ventricle that is ejected during systole. Normally, greater than 50%.

Right Atrial Pressure-RAP• Normal Value 2-8 mm Hg• Clinical Significance: Equivalent to central venous pressure.• Abnormalities:• Increased

– Right ventricular failure, tricuspid valve abnormalities (stenosis or regurgitation), cardiac tamponade, right ventricular infarct, VSD with a left to right shunt.

– Pulmonary stenosis, Postive Pressure ventilation – Pulmonary Hypertension

• Active: hypoxemic pulmonary vasoconstriction• Pa02 < 60 mm Hg.

– Pulmonary Embolus– COPD– ARDS

• Passive: – Mitral valve dysfunction either stenosis or regurgitation

Right Atrial Pressure-RAP

• Decreased:– Hypovolemia– Anything that vasodilates the body;

• Endogendous systemic vasodilation– Septic Shock, – Neurogenic Shock,– Anaphylactic Shock

• Venous vasodilation– Nitroglycerin or Morphine

Pulmonary Artery PressurePAP or PAS/D

• Systolic: 15-30 mm Hg• Diastolic: 5-12 mm Hg• Mean: 10-20 mm Hg

• Clinical Significance: PAP is equal to right ventricular pressure during systole while the pulmonary valve is open.

• IF the pulmonary vascular resistance is normal, the PADP is 1-4 mm Hg greater than PCWP and can be substituted for it in following the patient’s hemodynamic measurements.

• Abnormalities:Increased:– Hypervolemia, VSD with left to right shunt, Pulmonary

HTN, Positive pressure ventilation, Mitral valve dysfunction (both), Tamponade,

– Left ventricular failureDecreased:– Hypovolemia– Excessive vasodilation

• If the PADP is 5mm Hg > PCWP, consider acute respiratory distress syndrome, pulmonary emboli, or chronic obstructive pulmonary disease.

Pulmonary capillary wedge pressure PCWP or PAOP

• Normal value 5-12 mm Hg

• Clinical Significance: pcwp is normally equal to left atrial presure; ~sensitive indicator of pulmonary congestion or left sided CHF.

• PCWP is not equal to LVEDP in the following situations:

• PCWP >LVEDP: Mitral Stenosis, patients receiving PEEP, Left atrial myxoma, pulmonary venous obstruction

• PCWP< LVEDP:Stiff ventricle or Increased LVEDP (>25 mm Hg).

• Abnormalities: • Increased

– Left ventricular failure with resultant pulmonary congestions, acute mitralinsufficiency, tamponade, decreased left ventricular compliance (hypertropy, infarction).

• Decreased– Hypovolemia– Vasodilation

Cardiac OutputCO

• Normal Value 4-8 L/min.• Clinical Significance: CO=SV x heart rate/1000• Abnormalities:• Increased

– Sympathetic nervous system innervation(endogenous catecholamines ie. stress/exercise)

– Exogenous catecholamines (ie. epinephrine, dobutrex, dopamine, isuprel)

– Other positive inotropes ie. digitalis– Infection, early sepsis– Hyperthyroidism– Anemia

Cardiac Output-CO

• Decreased– Cardiac dysrhythmias, decreased contracting

muscle mass (myocardial infarction, ischemia) mitral insufficiency, VSD.

– Increased SVR (afterload)- systemic or Pulmonary HTN, Aortic or Pulmonic stenosisor polycythemia

– Significantly increased or decreased heart rate.

– Either hyper or hypovolemia

Cardiac IndexCI

• Normal Value: 2.5-4 L/min.

• Clinical Significance: CI= CO/BSA

• Abnormalities:• Increased: high output failure secondary to fluid

overload, hepatocellular failure, renal disease, septic shock

• Decreased: hypovolemia, cardiogenic shock, pulmonary embolism, hypothyroidism, CHF with failing ventricle.

Systemic Vascular resistanceSVR

• Normal Value 900-1300 dyne/sec/cm-5.

• SVR= (MAP-RAP) x 80 /CO• Clinical Significance: Resistance against which the

left ventricle must work to eject its stroke volume.• Abnormalities: • Increased: hypervolemic vasoconstrictive states

(hypertension, cardiogenic shock, traumatic shock). • Decreased: septic shock, acute renal failure,

pregnancy.

Remember

• There is a inverse relationship with CI and SVR.

• If the CI is UP, the SVR will be DOWN.• If the CI is DOWN, the SVR will be UP.

Pulmonary Vascular ResistancePVR

• Normal Value: 150-250 dyne/sec/cm-5.

• Clinical Significance: PVR=(mPAP-PCWP) x 80/CO.

• Abnormalities:• Increased: cor pulmonale, pulmonary embolism,

valvular heart disease, CHF.• Decreased: hypervolemic states, pregnancy.

Scenario

• 65 year old woman admitted with a fractured hip. She had surgery 2 weeks ago. Earlier today she complained about chest pain, shortness of breath, and a feeling of doom. ABG’s revealed respiratory alkalosis and hypoxemia. A RRT was called and she was transferred to ICU, the physician inserted a PA catheter into her right subclavian vein. He told the nurse it was placed so he could better diagnose and evaluate her thearpy. Her body surface area (BSA) is 1.6 m2.

Parameter ↑ ↓ or normal Why?Bp:112/84MAP: 93 mm HgHR: 110RAP: 18PAS/D: 55/32mPA: 40PAOP: 6CO: 4.4CI: 2.75

Parameter ↑ ↓ or normal Why?SaO2: 85%SV: 40

SVR: 1356PVR: 618Svo2: 58%

Dx: ______________ _________________

Considering her history, you would suspect ____________.

You know that means we gotta travel to have _____________________(test) done.Goals for this patient____________________________________________________________