Cardiac index

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Cardiac index (CI) is a haemodynamic parameter that relates the cardiac output (CO) from left ventricle in one minute to body surface area (BSA),[1] thus relating heart performance to the size of the individual. The unit of measurement is litres per minute per square metre (L/min/m2).

Calculation[edit]

The index is usually calculated using the following formula:

\text{CI} = \frac{\text{CO}}{\text{BSA}} = \frac{\text{SV}\times\text{HR}}{\text{BSA}}

where

CI 
Cardiac index
BSA 
Body surface area
SV 
Stroke volume
HR 
Heart rate
CO 
Cardiac output

Clinical significance[edit]

The normal range of cardiac index in rest is 2.6–4.2 L/min/m2.

The cardiac index is frequently measured and used in both intensive care medicine and cardiac intensive care. The CI is a useful marker of how well the heart is functioning as a pump by directly correlating the volume of blood pumped by the heart with an individual's body surface area.

If the CI falls below 1.8 L/min/m2, the patient may be in cardiogenic shock.

References[edit]