Hemodynamics

Question 1

How do you calculate the cardiac output? And what is the normal range?

Answer 1

CO = SV x HR
Normal = 4-8 L/min

Question 2

What is the normal cardiac index?

Answer 2

2.5-4L/min/m2

Question 3

What is stroke volume (SV) and what happens to CO if SV increases?

Answer 3

Stroke volume is how many mL per beat the left ventricle ejects. It is determined by the preload, afterload, and contractility.

If SV increases the CO increases

normal SV = 50-100ml/beat

Question 4

How do you measure afterload? What happens to the SV and CO as the afterload increases?

Answer 4

It is measured by the PVR (right ventricle) and SVR (left ventricle)

as afterload increases the SV and CO decrease

Question 5

What is a normal CVP (aka RAP)?

Answer 5

2-6mmHg

Question 6

what is a normal pulmonary artery pressure?

Answer 6

30-20/ 15-8

mean <20mmHg

Question 7

What is a normal PAOP?

Answer 7

8-12 mmHg

Question 8

what is a normal SVR?

Answer 8

800-1200 dynes/s/cm-5

(MAP -CVP) / CO x 80

Question 9

What is the normal for PVR?

Answer 9

50-250 dynes/s/cm-5

Question 10

what is the normal range for mixed venous oxygen saturation (SvO2)?

Answer 10

60-75%

Direct measurement in pulmonary artery

Question 11

what is the normal for a central venous oxygen saturation (ScvO2)?

Answer 11

> 70%

direct measurement in the superior vena cava

Question 12

what is the normal arterial oxygen saturation (SaO2)

Answer 12

95-99% on RA

Question 13

Dopamine at high doses will have an effect on what?

Answer 13

heart rate

Dopamine at high doses (11-20mcg) will increase BP, PAP, PAOP, CO, SV, SVR and PVR

Question 14

Levophed increases in all aspects of hemodynamics, but what does it have the greatest effect on?

Answer 14

SVR

no changes to HR

Question 15

Phenylephrine has a hemodynamic effect on which elements?

Answer 15

BP, SV/SI, SVR

Question 16

Epinephrine increases all aspects of hemodynamics but has the greatest effect on what?

Answer 16

SVR

increases the HR too

Question 17

Which medications increase your preload?

Answer 17

volume expanders (crystalloid, collids) 
pressors

Question 18

Which medications decrease your preload?

Answer 18

Diuretics
Dilators (nitrates, nitroprusside, nesiritide)
Morphine (vasodilates venous bed)

Question 19

Which medications increase your afterload?

Answer 19

Vasopressors

levo, neo, epi, and at high doses dopamine

Question 20

Which medications decrease your afterload?

Answer 20

ACE inhibitors
Calcium channel blockers
IABP
Nitroprusside
Nitroglycerin at high doses

Question 21

which medication increase contractility?

Answer 21

Positive inotropes

Dobutamine, Dopamine (5-10mcg/kg/min), Primacor, Epinephrine

Question 22

Which medications decrease your contractility?

Answer 22

negative Inotropes 
(Beta blockers, calcium channel blockers) 
Metabolic problems ( metabolic acidosis, endotoxins of sepsis)

Question 23

When would you see a “giant V wave” on a PAOP waveform?

Answer 23

During mitral valve insufficiency. This is associated with acute inferior wall myocardial infarction/papillary muscle disfunction/rupture

Question 24

What happens if you arterial waveform is overdamped?

Answer 24

results in falsely DECREASED SBP and falsely HIGH DBP as well as a diminished or absent dicrotich notch

this may be due to air or blood in the clot system, loose connections, loss of air in the pressure bad, kinking of the catheter/tubing system

Question 25

What happens if your arterial waveform is underdamped?

Answer 25

results in falsely HIGH SBP and a possible falsely low DBP and “ringing” artifact on the waveform

This may be due to pinpoint air bubbles in the system, add-on tubing, or defective transducer

Question 26

In cardiogenic shock, all compensatory mechanisms to maintain CO have failed, what hemodynamic profiles do you expect to be elevated in this type of shock?

Answer 26

PAOP and SVR

Elevated left ventricular preload (PAOP) with associated pulmonary symptoms
Elevated left ventricular afterload (SVR) due to vasoconstrictive compensatory mechanisms

Question 27

A patient is admitted with the following clinical findings: Chief complaint of SOB and fatigue, bibasilar crackles noted with S3 gallop, CT chest illustrated venous congestion and cardiomegaly, weight increase of 20lbs over the last two weeks.
Which of the following hemodynamics is found with this patient and what tx is indicated?
A. increase afterload, decrease contractility, and decrease preload;nesiritide to increase contractility
B. decrease afterload, decrease contractility, and increase in preload; lasix to increase afterload
C. decrease afterload, increased contractility, and increase preload; amiodarone to decrease preload
D. increase afterload, decrease contractility, and increased preload; dobutamine to increase contractility

Answer 27

D
The patient reflects heart failure. To compensate for the reduced cardiac output, a patient in heart failure vasconstricts. Therefore, afterload is high. Due to the low EF, the left heart pressures increase resulting in lung crackles, s3 heart sounds, and increase preload