Cardiac Hemodynamics

Question 0

What factors effect blood pressure?

Answer 0

Cardiac output and systemic vascular resistance.

Question 1

What is blood pressure?

Answer 1

Pressure in the systemic arteries which is created by the ejection of blood from the left ventricle.

Question 2

What is starlings law?

Answer 2

The greater the stretch of the ventricular muscle fiber, the greater the contraction, to a point. The more you stretch the harder you have to squeeze to get it all out.

Question 3

What is preload?

Answer 3

Occurs during diastole, the amount of blood filling the ventricles prior to the beginning of systole.
Volume that is trying to get into the heart
Pre-contraction

Question 4

What is afterload?

Answer 4

The pressure the heart has during every beat to send blood forward into the aorta. What is left in heart after contraction

Question 5

What are the forces that effect afterload?

Answer 5

Vasoactivity(blood vessel diameter and rigidity) and blood viscosity
The amount of blood after contraction

Question 6

Define contractility

Answer 6

The force of the cardiac muscle contraction

Question 7

What is cardiac output?

How is it determined?

Answer 7

The volume of blood pumped by the heart in one minute

HR x SV (stroke volume)= CO

Question 8

What is stroke volume?

Answer 8

The amount of blood pumped by the heart per cardiac cycle…ml/beat

Question 9

What are positive inotropes?

Answer 9

Any medication or circumstances that increase the force of cardiac contraction.
Sympathetic- fight or flight increases HR, contractility, more efficient

Question 10

What are negative inotropes?

Answer 10

Any medication or circumstances that decrease the force of cardiac contraction.
Parasympathetic- rest and digest, impairs contractility, relaxes smooth muscle

Question 11

Describe PVR?

Answer 11

Pulmonary vascular resistance- the measure of resistance of the pulmonary vascular bed to blood flow.

Question 12

What is SVR?

Answer 12

Systemic vascular resistance- the measurement of resistance of the systemic vascular bed to flow

Question 13

What is LVEF?

Answer 13

Left ventricular ejection fraction- also referred to ejection fraction
The % of blood ejected from the left ventricle during one cardiac cycle. The average is 55-65%

Question 14

What is CVP

Answer 14

Central venous pressure- Readings are used to assess right ventricular function and general fluid status using an invasive hemodynamic catheter.

Question 15

What is PA pressure?

Answer 15

BP in the pulmonary artery measured by invasive hemodynamic catheter.

Question 16

What is PAWP?

Answer 16

Pulmonary artery wedge pressure- are used to assess the preload of the left ventricle. Through a invasive catheter.

Question 17

What is preload mainly dependent on?

Answer 17

The return of venous blood from the body for the right ventricle and from the pulmonary system for the left ventricle.

Question 18

What is venous return influenced by?

Answer 18

Changes in position, intra-thoracic pressure, blood volume and the balance of constriction and dilation in the venous system.

Question 19

As preload increases, what does this do to the force of contraction?

Answer 19

A stronger contraction which is seen with an increase in SV and CO.

Question 20

How is preload measured?

Answer 20

Directly by the central venous pressure using an invasive catheter.