Mean Arterial Pressure (MAP)
Estimates average arterial pressure during a cardiac cycle
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Why use it
MAP is the primary hemodynamic target in septic shock and critical care management. It is more physiologically relevant than systolic BP for assessing organ perfusion. Used for vasopressor titration and hemodynamic monitoring.
About
Mean Arterial Pressure (MAP) represents the average arterial pressure throughout the cardiac cycle. It is considered a better indicator of tissue perfusion than systolic or diastolic pressure alone. MAP is a primary hemodynamic target in critical care, with most guidelines recommending MAP ≥ 65 mmHg to ensure adequate organ perfusion.
When to use
- Hemodynamic monitoring in ICU and perioperative settings
- Vasopressor titration targeting MAP ≥ 65 mmHg
- Assessment of cerebral perfusion pressure (CPP = MAP - ICP)
- Evaluation of shock states
Formula
Pearls & pitfalls
- MAP = DBP + 1/3(SBP - DBP), reflecting that ~2/3 of the cardiac cycle is in diastole.
- Target MAP ≥ 65 mmHg is recommended in septic shock (Surviving Sepsis Campaign).
- In traumatic brain injury, MAP targets are higher to maintain CPP > 60-70 mmHg.
- MAP measured by arterial line (gold standard) may differ from non-invasive cuff oscillometry.
- Chronic hypertension patients may need higher MAP targets to maintain organ perfusion.
Next steps
MAP < 65: consider fluid resuscitation and/or vasopressors. MAP > 100-110: evaluate for hypertensive emergency. For cerebral perfusion, calculate CPP = MAP - ICP.
Evidence
Surviving Sepsis Campaign (2021) recommends initial target MAP ≥ 65 mmHg. SEPSISPAM trial showed no benefit to targeting MAP 80-85 vs 65-70 except in chronic hypertension subgroup.