Cardiac output (CO) is the volume of blood the heart pumps per minute. It can be calculated using the following formula:
CO = HR × SV
Where:
• Stroke Volume (SV) is the amount of blood ejected by the left ventricle during each heartbeat, typically measured in milliliters (mL).
• Heart Rate (HR) is the number of heartbeats per minute.
Normal cardiac output for an adult at rest is typically around 4 to 8 liters per minute.
Methods to measure cardiac output (CO)-
1. Fick principle: Based on the oxygen consumption of the body.
2. Thermodilution: Involves the injection of a cold solution into the bloodstream and measuring the temperature change downstream.
3. Echocardiography: Uses ultrasound to measure blood flow and stroke volume.