Which expression correctly represents the mean arterial pressure?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Prepare for the AACN Essentials of Critical Care Nursing Test. Study with multiple choice questions and thorough explanations. Ace your test effortlessly!

Multiple Choice

Which expression correctly represents the mean arterial pressure?

Explanation:
Mean arterial pressure reflects the average pressure driving blood through the systemic circulation over a cardiac cycle, and because diastole lasts longer than systole, diastolic pressure should count more in the average. The standard approximation is to take SBP plus twice the DBP, then divide by three. This weighting is also equivalent to DBP plus one-third of the pulse pressure (where pulse pressure is SBP minus DBP). For example, with a BP of 120/80 mmHg, MAP ≈ (120 + 2×80)/3 = 280/3 ≈ 93 mmHg. Using DBP + 1/3(SBP − DBP) yields 80 + 1/3(40) ≈ 93 mmHg, the same result. The simple average (SBP + DBP)/2 would give about 100 mmHg here, which doesn’t reflect the longer diastolic phase. The other options don’t produce a physiologically meaningful MAP.

Mean arterial pressure reflects the average pressure driving blood through the systemic circulation over a cardiac cycle, and because diastole lasts longer than systole, diastolic pressure should count more in the average. The standard approximation is to take SBP plus twice the DBP, then divide by three. This weighting is also equivalent to DBP plus one-third of the pulse pressure (where pulse pressure is SBP minus DBP).

For example, with a BP of 120/80 mmHg, MAP ≈ (120 + 2×80)/3 = 280/3 ≈ 93 mmHg. Using DBP + 1/3(SBP − DBP) yields 80 + 1/3(40) ≈ 93 mmHg, the same result. The simple average (SBP + DBP)/2 would give about 100 mmHg here, which doesn’t reflect the longer diastolic phase. The other options don’t produce a physiologically meaningful MAP.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy