What is the normal range for Cardiac Index (CI)?

What is the normal range for Cardiac Index (CI)?

• A. 2.5 to 4.0 L/min/m²
• B. 1.0 to 2.0 L/min/m²
• C. 3.5 to 5.0 L/min/m²
• D. 4.0 to 6.0 L/min/m²

Answer: (A)

Cardiac index shows how much blood the heart pumps per minute for each square meter of body surface area, expressed as liters per minute per square meter. This normalizes cardiac output to body size so comparisons across people are meaningful. The typical normal range is about 2.5 to 4.0 L/min/m². It aligns with a standard resting cardiac output of around 5 L/min in an average adult and an average body surface area near 1.7 m² (5 ÷ 1.7 ≈ 2.9), with some margin for individual variation. Clinically, a value below about 2.5 suggests reduced cardiac performance or under-resuscitation, while a value above about 4.0 (up to roughly 4.5–4.0) can indicate high-output states or fluid/status changes. Cardiac index is measured using methods like thermodilution or Doppler echocardiography, and CI = CO divided by body surface area.

Cardiac index shows how much blood the heart pumps per minute for each square meter of body surface area, expressed as liters per minute per square meter. This normalizes cardiac output to body size so comparisons across people are meaningful. The typical normal range is about 2.5 to 4.0 L/min/m². It aligns with a standard resting cardiac output of around 5 L/min in an average adult and an average body surface area near 1.7 m² (5 ÷ 1.7 ≈ 2.9), with some margin for individual variation. Clinically, a value below about 2.5 suggests reduced cardiac performance or under-resuscitation, while a value above about 4.0 (up to roughly 4.5–4.0) can indicate high-output states or fluid/status changes. Cardiac index is measured using methods like thermodilution or Doppler echocardiography, and CI = CO divided by body surface area.