Certified Emergency Nurse (CEN) Practice Test 2026 - Free CEN Practice Questions and Study Guide

Mean Arterial Pressure (MAP) is an important physiological measurement that reflects the average blood pressure in a person's arteries during one cardiac cycle. It is particularly significant because it provides an indication of blood flow to vital organs.

The formula for calculating MAP is derived from the physiology of the cardiac cycle, specifically considering that the heart spends more time in diastole than in systole. This is why the diastolic pressure is multiplied by two in the calculation.

Using the formula (2x diastolic + systolic) / 3 properly accounts for the longer duration of diastolic pressure compared to systolic pressure. By emphasizing diastolic pressure in this way, the calculation yields a more accurate representation of the average pressure that perfuses the body's organs.

Other options do not reflect this physiological understanding:

- The approach of averaging systolic and diastolic pressures equally does not consider the relative time spent in each phase of the cardiac cycle, which can result in a misleading value that does not accurately indicate organ perfusion.

- Similarly, the formulas that incorrectly weight systolic pressure more heavily than diastolic pressure do not provide a proper estimate of the MAP.

Thus, recognizing the correct calculation, (2x diastolic