Question

Describe in detail preload, afterload and how they affect the cardiac output of the heart muscle for both the right and left side of the heart.

Describe a pathophysiological disorder that is affected by or caused by changes in cardiac output, addressing preload and afterload, i.e. CHF, hypertension, pulmonary hypertension, etc.

Describe at least three nursing interventions that can help to improve the flow of blood in relation to the above disorder.

Answer 1

preload

during diastole, the left and right ventricle dilate and fills by blood to pump during systole. at this time, ventricle stretches to a certain extent. So, preload is the amount of ventricular stretch at the end of diastole, is also known as left ventricular end-diastolic pressure (LVEDP).

Afterload

Afterload is the pressure applied by the heart to open the aortic valve for pumping blood to different parts of the body. so, it is also known as systemic vascular resistance (SVR).

Cardiac output is the volume of blood ejected from the left or right ventricle each minute. And it is the product of stroke volume and heart rate. Stroke volume is the difference between end diastolic volume and end systolic volume. end systolic volume is affected by preload, afterload, heart rate and contractility.

in case of any blood loss or rapid heart rate, preload increases and heart stretchability increases and thus affects ventricular contraction.

Pulmonary hypertension (PH) is high blood pressure in the arteries to the lungs. the blood vessels that carry blood from the heart to the lungs become hard and narrow. so, the heart has to work hard to pump the blood, results in weakening of heart.