Hemodynamic Parameters

Question 1

RAP (Right arterial Pressure/CVP (Central Venous Pressure)

Explain CVP and RAP

Answer 1

1-8 mmHG
CVP is the pressure of blood in the thoracic vena cava, near the right atrium. CVP reflects the amount of blood returning to the heart. CVP is a good approximation of RAP.

Question 2

PAP (Pulmonary Arterial Pressure)

Answer 2

15-26 mmHg systolic
5-15 mmHg diastolic
8-12 mmHg mean

Question 3

Explain the PAP

Answer 3

Normal pulmonary artery systolic pressure: 15-26 mmHg.
Systolic pressure reading of a P.A. catheter represents right ventricular ejection of blood into the pulmonary arteries.
Normal pulmonary diastolic pressure: 5-15 mm Hg.
Diastolic pressure reading of a P.A. catheter represents the run-off of blood from the pulmonary arteries to the pulmonary veins and left ventricle.

Question 4

PCWP (Pulmonary Capillary Wedge Pressure)

Answer 4

4-12 mmHg

Question 5

Explain the PCWP

Answer 5

Pulmonary capillary wedge pressure reflects the amount of blood filling the left ventricle.

Question 6

SVR (Systemic Vascular Resistance)

Answer 6

800-1200 dynes/sec/cm-5

Question 7

Explain SVR

Answer 7

SVR is the measure of afterload for the left ventricle.

SVR is determined by the radius of the arterioles, viscosity of the blood, and the length of the vessels

Question 8

What causes in increase in SVR

Answer 8

Hypertension, Hypothermia, vasoconstriction of arterial bed

Question 9

PVR (Pulmonary Vascular Resistance)

Answer 9

20-120 dynes/sec/cm-5

Question 10

Explain PVR

Answer 10

Rresistance that the right ventricle must overcome to eject blood into the pulmonary arteries.

Question 11

An increase in PVR leads to?

Answer 11

With increased PVR patients can develop right sided heart failure known as Cor Pulmonale.

Question 12

EF (Ejection Fraction)

Explain

Answer 12

60-70%

The percentage of blood the left ventricle pumps out with each contraction (stroke)

Question 13

SV (Stroke Volume)

Explain

Answer 13

70-80ml

Stroke volume is the amount of blood ejected by the left ventricle in one contraction

Question 14

SV is influenced by

Answer 14

preload, afterload, and contractility

Question 15

CO (cardiac output)
How do you calculate CO?
Explain CO

Answer 15

4-8 L/min
HR x SV
Cardiac output is the volume of blood pumped by the heart per minute (mL blood/min)

Question 16

CI (Cardiac Index)
How to calculate CI?
Explain CI

Answer 16

2.5-4 L/m2
CO/BSA
Cardiac Index is a more accurate measurement of cardiac output because it takes into account the patient’s body surface area (BSA)

Question 17

Explain Preload

Answer 17

Stretching of the ventricle when blood enters the ventricle at end diastole. The more the heart muscle stretches the forceful the contraction will be during systole

Question 18

How do you measure preload

Answer 18

RAP/CVP for right ventricle

PCWP for left ventricle

Question 19

Explain Contractility

Answer 19

Refers to the ability of the ventricle to stretch to contract.
The greater the stretch the greater the contractility.

Question 20

What influence contractility and how?

Answer 20

Influenced by Preload and afterload
If preload is too hight or too low contractility can be decreased.
If afterload is too high, contractility can be decreased because heart muscle may not be able to overcome the high resistance.

Question 21

Explain Afterload

Answer 21

Refers to the pressure the ventricle must generate to overcome the higher pressure in the aorta (pulmonary artery) to get the blood out of the heart (or right ventricle in the PA).

Question 22

How is afterload measured?

Answer 22

SVR in the left ventricle.

PVR for the right ventricle.

Question 23

Explain Compliance

Answer 23

Compliance of the ventricle is the ability to stretch.
If compliance decreases (ventricle is stiff) the pressure of the ventricle will decrease d/t less blood entering the ventricle.

Question 24

Normal MAP

How to calculate the MAP

Answer 24

70-110 mmHg

MAP= Systolic + (2)Diastolic/ 3

Question 25

Explain the MAP

Answer 25

MAP is the average pressure in the arterial system during systole and diastole. It tells us how well all organs are perfused