What is Cardiac Output definition/concept
The medical specialty that focuses on the functioning of the heart is cardiology. It is the branch that studies all the elements and processes that are part of the heart’s functions.
It is the volume of blood that pumps the heart in one minute
Cardiac output is measurable and dilution methods are used for this. In this method, an amount of marker substance (dyes) is injected into a vein close to the heart, later this substance circulates through the blood through the right ventricle, lungs and the left ventricle of the heart, appearing a marker substance in the arterial system .
Then, a monitoring probe is inserted into the aorta artery and a blood sample is taken at that time to measure the concentration of dye leaving the heart until all the dye passes through the monitoring point . This procedure allows measuring cardiac output through a formula. The unit of measurement for cardiac output is established in liters per minute. It is worth remembering that this methodology is constantly being improved in order to be as less invasive as possible.
This depends on two factors or variables: heart rate and stroke volume (in physiology the formula cardiac output = HR x VE is used). The average HR of a human being is 70 beats per minute and the average ejection volume is 70 milliliters.
In other words, each contraction of the heart produces 70 milliliters of blood which is equivalent to 70×70, on average equal to 4900 liters per minute of cardiac output. This means that the increase in one of the variables (HR or VE) increases cardiac output itself, and the decrease in one of the variables decreases cardiac output. This is important as the heart must maintain its cardiac output at stable values.
What is the use of measuring cardiac output?
The heartbeat works as a combined electrical and mechanical system that allows the heart muscle to work involuntarily.
Knowing the specific data regarding an individual’s cardiac output allows us to have information relevant to many senses: knowing a person’s cardiovascular health , to resuscitate patients with heart failure, to prevent changes (eg, possible clots), to indicate adequate exercise , to perform surgeries with lower risk , to reduce mortality or for hospital admission to be as brief as possible.