How is mean arterial pressure commonly approximated in basic physiology?

Study for the Paramedic Aandamp;P Exam. Engage with flashcards and multiple choice questions, complete with hints and explanations. Prepare effectively for your exam!

Multiple Choice

How is mean arterial pressure commonly approximated in basic physiology?

Mean arterial pressure represents the average pressure driving blood through the arteries over the whole cardiac cycle. Because diastole lasts longer than systole, the diastolic pressure contributes more to the overall pressure. This is why a time-weighted average uses diastole twice as much as systole in the calculation: MAP ≈ (SBP + 2×DBP) / 3. For example, with a systolic pressure of 120 and a diastolic pressure of 80, MAP ≈ (120 + 160) / 3 ≈ 93 mmHg. The other formulas don’t reflect this time weighting: subtracting DBP from SBP gives pulse pressure, not the average pressure; multiplying SBP by DBP then halving has no physiological basis for an average; averaging SBP and DBP assumes equal time in each phase, which isn’t the case.

Mean arterial pressure represents the average pressure driving blood through the arteries over the whole cardiac cycle. Because diastole lasts longer than systole, the diastolic pressure contributes more to the overall pressure. This is why a time-weighted average uses diastole twice as much as systole in the calculation: MAP ≈ (SBP + 2×DBP) / 3. For example, with a systolic pressure of 120 and a diastolic pressure of 80, MAP ≈ (120 + 160) / 3 ≈ 93 mmHg. The other formulas don’t reflect this time weighting: subtracting DBP from SBP gives pulse pressure, not the average pressure; multiplying SBP by DBP then halving has no physiological basis for an average; averaging SBP and DBP assumes equal time in each phase, which isn’t the case.

More practice questions