How to Calculate Mean Arterial Pressure
What is Mean Arterial Pressure?
Mean arterial pressure represents average blood pressure throughout the cardiac cycle. It's calculated from systolic and diastolic pressures.
Formula
Calculate: MAP = DBP + (SBP - DBP)/3 or MAP = (SBP + 2×DBP)/3
- MAP
- DBP + (SBP - DBP)/3 or MAP = (SBP + 2×DBP)/3 — DBP + (SBP - DBP)/3 or MAP = (SBP + 2×DBP)/3
- DBP
- (SBP + 2×DBP)/3 — (SBP + 2×DBP)/3
- SBP
- (SBP + 2×DBP)/3 — (SBP + 2×DBP)/3
Step-by-Step Guide
- 1Calculate: MAP = DBP + (SBP - DBP)/3 or MAP = (SBP + 2×DBP)/3
- 2Normal MAP ≈ 90 mmHg in adults
- 3MAP <60 mmHg risks end-organ damage
Worked Examples
Input
SBP 120, DBP 80
Result
MAP = 93 mmHg (normal)
Also can use (120 + 160)/3
Common Mistakes to Avoid
- ✕Treating MAP as if it directly correlates to systolic (it doesn't)
- ✕Forgetting that diastolic weighs more than systolic in formula
Frequently Asked Questions
Why is MAP important?
It better reflects perfusion pressure than systolic alone; organs require minimum MAP (~60 mmHg) to function.
How do vasopressors work?
They increase systolic/diastolic pressure, raising MAP to improve organ perfusion in shock.
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