AIIMS November 2011 – MCQ 196
Mean arterial pressure is calculated as:
A. (SBP+2DBP)/3
B. (DBP+2SBP)/3
C. (SBP+3DBP)/2
D. (DBP+3SBP)/2
(Repeat question – AIIMS Nov 06 – AA q14)
Correct answer: A. (SBP+2DBP)/3
Mean arterial pressure
= Diastolic pressure + 1/3 pulse pressure
= DBP + 1/3 (SBP-DBP)
= (3DBP+SBP-DBP)/3
= (SBP+2DBP)/3
One Comment
Physiologically, the pressure that is primarily regulated is the mean arterial pressure. This is the average level of the blood pressure over several heart beats. This could be determined by measuring the blood pressure at many closely spaced intervals and averaging the numbers. But this is not necessary, since it can be estimated satisfactorily by adding one-third of the pulse pressure (see below) to the diastolic pressure.
Mean Arterial Pressure ~= 1/3 * SBP + 2/3 * DBP
http://www.mdcalc.com/mean-arterial-pressure-map
http://courses.washington.edu/conj/circulation/reflectedPulse.htm