**Question:** Which of the following is a cause of wide pulse pressure:

A. Increased cardiac output
B. Decreased arterial resistance
C. Increased heart rate
D. Decreased peripheral resistance

**Core Concept:** Wide pulse pressure is defined as the difference between systolic blood pressure and diastolic blood pressure. Normal pulse pressure is usually between 20-40 mmHg, but in certain conditions, it may widen.

**Why the Correct Answer is Right:** Wide pulse pressure can result from increased cardiac output (CO). Increased CO means that the heart is pumping more blood per minute, leading to higher systolic blood pressure. Decreased arterial resistance (DAR) may also contribute to wide pulse pressure because it allows for more blood to be ejected by the heart with each beat, further increasing systolic blood pressure relative to diastolic blood pressure.

**Why Each Wrong Option is Incorrect:**

A. Decreased cardiac output (DCO) would lead to a decreased systolic blood pressure, not a wide pulse pressure.
B. Decreased peripheral resistance (DPR) would cause a decrease in systolic blood pressure and potentially a decrease in pulse pressure, not increase it.
C. Increased heart rate (IHR) can increase the pulse pressure but does not directly cause a wide pulse pressure, unless there is also increased cardiac output or decreased peripheral resistance.

**Clinical Pearl:** A wide pulse pressure can be a sign of multiple cardiovascular conditions, including aortic stenosis, aortic regurgitation, left ventricular hypertrophy, and sepsis. A narrow pulse pressure is more commonly seen in conditions like dehydration, shock, and advanced age.

**Correct Answer:** D. Decreased peripheral resistance (DPR) is the correct answer because it allows for a larger systolic blood pressure increase relative to the diastolic blood pressure decrease, resulting in a wider pulse pressure.