Cardiac Hemodynamics Flashcards

1
Q

What is the normal range of central venous pressures (CVP)?

A

0-6

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2
Q

What is the normal range for right atrial (RA) pressures?

A

0 - 8

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3
Q

What is the normal range for right ventricular pressures?

A

20 - 30 systolic
0 - 8 diastolic

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4
Q

What is the normal range for pulmonary artery pressures?

A

20 - 30 systolic
8 - 15 diastolic

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5
Q

What is the normal range for left atrial (LA, or PCWP) pressures?

A

4-12

Note: Pulmonary artery wedge pressure obtained with a Swan will typically be 0-5 mm Hg higher than the actual PCWP

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6
Q

What is the normal range for left ventricular pressures?

A

100 systolic
5 diastolic

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7
Q

What is the normal range for aortic pressures?

A

100 systolic
60 diastolic

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8
Q

What is the formula for pulmonary vascular resistance?

A

(meanPAP - PCWP) / CO

PAP: Pulmonary artery pressure
PCWP: Pulmonary capillary wedge pressure
CO: Cardiac output

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9
Q

PVR is the recommended parameter for differentiating subtypes of ______.

A

Pulmonary hypertension

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10
Q

What is the type of pulmonary hypertension present if:
PVR >= 3 WU
PCWP >= 15

A

Combined post- and pre-capillary PH

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11
Q

What is the type of pulmonary hypertension present if:
PVR >= 3 WU
PCWP < 15

A

Isolated pre-capillary PH

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12
Q

What is the type of pulmonary hypertension present if:
PVR < 3 WU
PCWP >= 15

A

Isolated post-capillary PH

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13
Q

What is the type of pulmonary hypertension present if:
PVR < 3
PCWP < 15

A

N/A; consider high flow state

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14
Q

What is the formula for systemic vascular resistance? What is the normal range?

A

[(MAP - CVP)/CO] x 80
Normal range 800-1200 dynes-sec/cm^5

MAP: Mean arterial pressure
CVP: Central venous pressure (or right atrial pressure)
CO: Cardiac output

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15
Q

Advanced cardiogenic shock may have a ____ or ____ SVR.

A

low
normal

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16
Q

What is cardiac power output (CPO)? What is the formula for CPO? Why is this useful?

A

Cardiac Power Output (CPO) reflects the hydraulic energy delivered by the LV.
CPO is calculated by (MAP x CO)/451
CPO of <0.6 was the strongest independent hemodynamic correlate in the SHOCK trial registry for in-hospital mortality in patients with cardiogenic shock

17
Q

What is LV transmural filling pressure? How is it calculated? Why is it important?

A

LV transmural filling pressure reflects the pressure difference between the LV and its external forces, and influences LV filling
LV transmural filling pressure is calculated by: PCWP - CVP
Increases in CVP or pericardial pressure can reduce LV filling, stroke volume, and forward flow e.g., PE, right heart failure

18
Q

What is the conversion between Wood units and dynes-sec/cm^5?

A

1 Wood unit = 80 dynes-sec/cm^5

19
Q

What is Pulmonary Artery Pulsatility Index? How is it calculated? Why is it useful?

A

-The Pulmonary Artery Pulsatility Index (PAPI) is a predictor of RV failure in inferior MI.
-PAPi = (sPAP - dPAP)/CVP
-PAPi =<0.9 predicts RV failure and in-hospital mortality in inferior MI
-PAPi =<1.85 predicts RV failure in patients with LVADs

sPAP = systolic Pulmonary Artery Pressure
dPAP = diastolic Pulmonary Artery Pressure
CVP = Central Venous Pressure (also known as right atrial pressure)

20
Q

What does the CVP/PCWP ratio correlate with? What are important thresholds for this ratio?

A

An elevated CVP/PCWP ratio correlates with RV dysfunction.
-CVP/PCWP > 0.8 indicates RV dysfunction in patients with cardiogenic shock
-CVP/PCWP > 0.54 predicted RV dysfunction in patients with LVADs

21
Q

What is the normal range for cardiac output?

A

4-8 L/min

22
Q

How is cardiac index calculated? What is the normal range?

A

Cardiac index = CO/BSA
-Normal range is from 2.5-4 L/min/m^2

CO: Cardiac output
BSA: Body surface area

23
Q

Shock + CI < ____ usually indicates a “COLD” profile

A

2.2

24
Q

Bedside clue to a low CI: The proportional pulse pressure _________ of less than _____ suggests a cardiac index of less than 2.2 L/min/m^2

A

(SBP-DBP)/SBP
25%

SBP: systolic blood pressure
DBP: diastolic blood pressure

25
Q

What are the two methods by which cardiac output can be determined?

A

Thermodilution and Fick

26
Q

What is the gold standard for measuring cardiac output?

A

Direct Fick

27
Q

What are the two assumptions made when calculating cardiac output by Fick and TD?

A

Both methods are based on the assumption that pulmonary blood flow is equal to systemic blood flow and that there is no intracardiac shunt

28
Q

What is the principle behind the TD method of calculating cardiac output?

A

Washout of a temperature change induced by injection of a defined fluid volume cooler than the body temperature. The faster the circulation or flow (increased cardiac output), the quicker the neutralization of the temperature change.

29
Q

What is the principle behind the Fick method of calculating cardiac output? What is the formula?

A

Blood flow is proportional to the rate of oxygen uptake in the lungs and the difference in the concentration of oxygen between arterial and venous blood

CO = oxygen consumption / (Arterial O2 content - Venous O2 content)

30
Q

What is Left Ventricular Stroke Work Index (LVSWI)? How is it calculated?

A

LVSWI is an assessment of LV systolic and diastolic function and has been strongly associated with mortality in CICU patients.

LVSWI = (MAP-PCWP) x SVI x 0.136

LVSWI: Left Ventricular Stroke Work Index
MAP: Mean arterial pressure
PCWP: Pulmonary capillary wedge pressure
SVI: Stroke Volume Index

31
Q

What is Right Ventricular Stroke Work Index? How is it calculated?

A

RVSWI is a measure of RV systolic and diastolic function.

RVSWI = (mPAP - CVP) x SVI x 0.136

RVSWI: Right Ventricular Stroke Work Index
mPAP: mean Pulmonary Artery Pressure
CVP: Central venous pressure
SVI: Stroke Volume Index

32
Q

What is the formula for Stroke Volume Index?

A

SVI = Cardiac Index / Heart rate

33
Q

List the waveforms and descents on a right atrial pressure tracing in order.

A

a wave
c wave
x descent
v wave
y descent

34
Q

On a right atrial pressure tracing, what does the following correlate to:
a wave

A

Contraction in atrial systole

35
Q

On a right atrial pressure tracing, what does the following correlate to:
c wave

A

Closure of the tricuspid valve

36
Q

On a right atrial pressure tracing, what does the following correlate to:
x descent

A

Fall in RA pressure (isovolumic relaxation)

37
Q

On a right atrial pressure tracing, what does the following correlate to:
v wave

A

Ventricular systole + passive atrial filling in atrial diastole

38
Q

On a right atrial pressure tracing, what does the following correlate to:
y descent

A

Fall in RA pressure following opening of the TV + passive filling of RV

39
Q

What is the normal range of mean Pulmonary Artery Pressure (mPAP)?

A

12 - 16 mmHg