Cardiac Hemodynamics

Question 1

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

Answer 1

0-6

Question 2

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

Answer 2

0 - 8

Question 3

What is the normal range for right ventricular pressures?

Answer 3

20 - 30 systolic
0 - 8 diastolic

Question 4

What is the normal range for pulmonary artery pressures?

Answer 4

20 - 30 systolic
8 - 15 diastolic

Question 5

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

Answer 5

4-12

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

Question 6

What is the normal range for left ventricular pressures?

Answer 6

100 systolic
5 diastolic

Question 7

What is the normal range for aortic pressures?

Answer 7

100 systolic
60 diastolic

Question 8

What is the formula for pulmonary vascular resistance?

Answer 8

(meanPAP - PCWP) / CO

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

Question 9

PVR is the recommended parameter for differentiating subtypes of ______.

Answer 9

Pulmonary hypertension

Question 10

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

Answer 10

Combined post- and pre-capillary PH

Question 11

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

Answer 11

Isolated pre-capillary PH

Question 12

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

Answer 12

Isolated post-capillary PH

Question 13

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

Answer 13

N/A; consider high flow state

Question 14

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

Answer 14

[(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

Question 15

Advanced cardiogenic shock may have a ____ or ____ SVR.

Answer 15

low
normal

Question 16

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

Answer 16

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

Question 17

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

Answer 17

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

Question 18

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

Answer 18

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

Question 19

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

Answer 19

-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)

Question 20

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

Answer 20

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

Question 21

What is the normal range for cardiac output?

Answer 21

4-8 L/min

Question 22

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

Answer 22

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

CO: Cardiac output
BSA: Body surface area

Question 23

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

Answer 23

2.2

Question 24

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

Answer 24

(SBP-DBP)/SBP
25%

SBP: systolic blood pressure
DBP: diastolic blood pressure

Question 25

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

Answer 25

Thermodilution and Fick

Question 26

What is the gold standard for measuring cardiac output?

Answer 26

Direct Fick

Question 27

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

Answer 27

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

Question 28

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

Answer 28

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.

Question 29

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

Answer 29

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)

Question 30

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

Answer 30

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

Question 31

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

Answer 31

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

Question 32

What is the formula for Stroke Volume Index?

Answer 32

SVI = Cardiac Index / Heart rate

Question 33

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

Answer 33

a wave c wave x descent v wave y descent

Question 34

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

Answer 34

Contraction in atrial systole

Question 35

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

Answer 35

Closure of the tricuspid valve

Question 36

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

Answer 36

Fall in RA pressure (isovolumic relaxation)

Question 37

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

Answer 37

Ventricular systole + passive atrial filling in atrial diastole

Question 38

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

Answer 38

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

Question 39

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

Answer 39

12 - 16 mmHg