American Association of Critical-Care Nurses (AACN) Certification Practice Test

What is the normal range for cardiac index (CI)?

1. 1.5-2.5 L/min/m^2

2. 2.5-4 L/min/m^2

3. 4-6 L/min/m^2

4. 6-8 L/min/m^2

The correct answer is: 2.5-4 L/min/m^2

The cardiac index (CI) is an important measure that reflects the cardiac output of a patient normalized to their body surface area. It allows healthcare providers to assess the efficiency of the heart in pumping blood relative to the size of the individual. The normal range for cardiac index is typically between 2.5 to 4 L/min/m². Values within this range indicate adequate blood flow to meet the metabolic demands of the body's tissues. When the cardiac index is below this range, it may suggest diminished cardiac output and can be indicative of conditions such as heart failure, whereas values above this range may not necessarily indicate over-performance but could be a result of other factors such as hyperdynamic states seen in sepsis or fluid overload. Monitoring the cardiac index helps clinicians in the management of critically ill patients, allowing for timely interventions. The other ranges provided do not align with accepted clinical standards for normal cardiac index values, further clarifying that the designated range is the appropriate measure of cardiac performance in relation to body size.