**Cardiac Output - A Measure of Cardiac Performance**

**Core Concept**
Cardiac output (CO) is a critical physiological parameter that represents the volume of blood the heart pumps per minute. It is a key indicator of cardiac performance and is essential for maintaining adequate tissue perfusion and oxygenation.

**Why the Correct Answer is Right**
Cardiac output is a measure of the stroke volume (SV) multiplied by the heart rate (HR). The stroke volume is the volume of blood ejected by the left ventricle with each beat, while the heart rate is the number of beats per minute. The formula for calculating cardiac output is CO = SV x HR. This is a fundamental principle in cardiovascular physiology, and understanding this relationship is crucial for evaluating cardiac function and diagnosing cardiovascular diseases.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because cardiac output is not a measure of blood pressure. While blood pressure is related to cardiac output, they are not synonymous terms.

**Option B:** This option is incorrect because cardiac output is not a measure of peripheral resistance. Peripheral resistance is a factor that affects blood pressure, but it is not directly related to cardiac output.

**Option C:** This option is incorrect because cardiac output is not a measure of oxygen delivery to tissues. Oxygen delivery is a function of cardiac output, but they are not the same thing.

**Clinical Pearl / High-Yield Fact**
Cardiac output is a dynamic parameter that can be affected by various factors, including changes in blood volume, heart rate, and contractility. It is essential to consider these factors when interpreting cardiac output measurements in clinical practice.

**Correct Answer: C. Volume of blood the heart pumps per minute.**