Hemodynamic Monitoring

Question 1

Cardiac Output = ___ x ____

Answer 1

HR x SV
heart rate
stroke volume = amount of blood ejected by ventricle w/ each contraction

Question 2

Normal cardiac output value

Answer 2

4.0 to 8.0 L/min

Question 3

what is cardiac index?

Answer 3

it is the CO that has been adjusted to individual body size based on BSA (body surface area)
CI = CO divided by BSA

Question 4

Normal cardiac index value

Answer 4

2.5 to 4.3 L/min/m^2

Question 5

Normal stroke volume

Answer 5

60 to 100 ml/beat

Question 6

Stroke volume is dependent on what 3 things

Answer 6

preload, afterload, and contractility

Question 7

What are the two categories of impairment to the Left ventricle causes decreased stroke volume (which also decreases cardiac output)

Answer 7

1- inadequate ventricle filling

2- inadequate ventricle emptying

Question 8

Common causes of an increase in pulmonary vascular resistance (PVR)

Answer 8

• pulmonary hyptertension
• pulmonary embolism
• hypoxia
• end stage COPD (cor pulmonale)

Question 9

Factors that affect contractility (bedsides preload & afterload)

Answer 9

• electrolyte levels
• myocardial oxygenation (ischemia)
• amount of functional myocardium (infarction, cardiomyopathy)
• postive/negative inotropic medications

Question 10

Arterial catheter (“A-line”)

1. how the tubing differs from normal IV tubing
2. what type of solution can be used
3. how much pressure mm Hg is placed on the IV bag
4. most common sites

Answer 10

1. it is stiff and noncompliant and is kept as short as possible (no more than 3-4 ft)
2. most common- NS but D5W can be used
3. 300 mm Hg
4. radial- most common; also brachial, axillary, femoral, or pedal

Question 11

Where is the phlebostatic axis?

Answer 11

The intersection between the 4th ICS and half the AP diameter of the chest

Question 12

Valsalva maneuver examples

Answer 12

• excessive bearing down during bowel movement
• vomiting
• coughing
• suctioning

Question 13

Medications that decrease HR (negative chronotropic)

Answer 13

• digitalis
• BB’s
• Calcium channel blockers
• phenlyephrine

Question 14

Physiologic causes of increased HR

Answer 14

• stress
• anxiety
• pain
• conditions that result in release of catecholamines: hypovolemia, fever, anemia, hypotension

Question 15

Medications that have direct positive chronotropic effect

Answer 15

epinephrine, dopamine

Question 16

Two most common causes of low stroke volume

Answer 16

• hypovolemia

- LV dysfunction

Question 17

What is a normal Ejection Fraction (EF) and how can one measure the EF?

Answer 17

• > 60%

- can be evaluated with a PA catheter or an echocardiogram

Question 18

3 Etiologies of RV (right ventricular) failure

Answer 18

1) intrinsic disease ie RV infarct, cardiomyopathy
2) secondary factors that increase PVR (ie pulm artery HTN, PE, hypoxemia, COPD, acute ARDS, sepsis)
3) severe LV dysfunction ie: mitral stenosis/insufficiency or LV failure

Question 19

Normal preload in RV vs LV

Answer 19

Normal RV preload: 2 - 8 mm Hg –> aka RAP

Normal LV preload: 8 - 12 mm Hg –> aka LAP or PAOP/PCWP/PAWP

Question 20

How to measure preload in RV vs LV

Answer 20

RV: preload measured w/ CVP catheter &/or PA catheter
LV: preload measured w/ PA catheter

Question 21

3 Factors that alter vascular resistance

Answer 21

1) length of a vessel (constant)
2) viscosity of blood (usually constant)
3) diameter/radius of the vessel

Question 22

What are common causes of increased Pulmonary vascular resistance (PVR) and which part of the heart does an elevated PVR cause strain on?

Answer 22

• common causes of increased PVR= pulmonary HTN, hypoxia, end stage COPD (cor pulmonale), PE
• causes strain on the R ventricle

Question 23

Normal range for mixed venous oxygen saturation

Answer 23

60 - 80%