BLOOD OUTPUT OF THE HUMAN HEART (CARDIAC OUTPUT)
INTRODUCTION
Blood output of the heart is the quantity of blood that is being pumped from each ventricle of the heart, most importantly, from the left ventricular output through aorta.
Heart's blood output is expressed in three ways viz:
- Stroke volume.
- Minute volume.
- Cardiac index.
1. STROKE VOLUME: This is the amount of blood being pumped out by each ventricle during each beat. Its average value is 70ml during normal heart rate I.e 72beat/minute.
2. MINUTE VOLUME: This is the amount of blood that is being pumped out by each ventricle of the heart in one minute. And it's the product of stroke volume and heart rate. I.e
Minute vol. = Stroke vol. × Heart rate
3. CARDIAC INDEX: This is the expression of the minute volume in relationship with
the square meter of the body surface area. That is the amount of blood being pumped out per ventricle per minute per square meter of the surface area of the body.
In an adult with an average body surface area of 1.734 square meter and normal minute volume of 5L/minute, normal value for Cardiac Index is: 2.8 +or- 0.3 L/square meter of the body surface area/min....