How MAP is calculated
Mean Arterial Pressure is the time-averaged pressure in the arteries over one cardiac cycle. Because diastole lasts roughly twice as long as systole, the formula weights diastolic pressure twice as heavily.
This estimate closely approximates the true area-under-the-curve MAP obtained from an arterial line waveform.
Normal values
| MAP (mmHg) | Interpretation |
|---|---|
| < 60 | Below organ perfusion threshold |
| 60 – 64 | Below sepsis resuscitation target |
| 65 – 100 | Normal / adequate perfusion |
| > 100 | Elevated |
Clinical use
MAP better reflects organ perfusion pressure than systolic pressure alone, since it's what drives blood flow to the brain, kidneys, and other organs across the cardiac cycle. A MAP of ≥65 mmHg is the standard initial resuscitation target in septic shock (titrated with fluids and vasopressors); a MAP below ~60 mmHg risks inadequate coronary, cerebral, or renal perfusion. Individualised targets (e.g. higher in chronic hypertensives, or per cerebral perfusion pressure calculations in traumatic brain injury) may override the general target.
Frequently asked questions
What is mean arterial pressure (MAP)?
MAP is the average pressure driving blood flow through the arteries over one full cardiac cycle — a better reflection of organ perfusion pressure than systolic pressure alone.
What is a normal MAP?
65–100 mmHg is generally considered adequate for organ perfusion in most adults; below 60 mmHg risks inadequate perfusion of vital organs.
What MAP is the target in sepsis?
Surviving Sepsis Campaign guidelines target a MAP of at least 65 mmHg during initial resuscitation, titrated with fluids and vasopressors as needed.
Why is MAP more useful than blood pressure alone?
Because diastole lasts roughly twice as long as systole, MAP weights diastolic pressure more heavily, better representing the pressure organs actually experience across the full cardiac cycle rather than just the systolic peak.
References
- Evans L, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Crit Care Med. 2021;49:e1063–e1143.