Cardiac Index Calculator

The cardiac index (CI) normalizes cardiac output (CO) to an individual's body surface area (BSA), making it a reliable metric across different body types. First, cardiac output is determined by multiplying stroke volume (in milliliters, converted to liters) by heart rate. The formula is: Cardiac Output = (Stroke Volume / 1000) × Heart Rate. Next, Body Surface Area is estimated using the Mosteller formula based on height and weight. Finally, the Cardiac Index is computed as: CI = Cardiac Output / BSA.

Consider an adult patient with a stroke volume of 75 mL, a heart rate of 80 beats per minute, a height of 175 cm, and a weight of 70 kg. First, we find the cardiac output: (75 / 1000) × 80 = 6.0 liters per minute. Next, using the height and weight for BSA calculation via the standard formula, we get approximately 1.83 square meters. Dividing the cardiac output by the BSA gives a Cardiac Index of 6.0 / 1.83 = 3.28 L/min/m², which falls within the normal resting adult range.

Always ensure your input units match the required specifications (such as centimeters for height and kilograms for weight) to prevent calculation errors. Remember that normal ranges can vary slightly depending on clinical context, age, and resting state. Use this tool for educational, preliminary estimation, and always consult a certified medical professional for formal diagnoses.