Scores & indices
MAP calculator
Systolic gets the attention; the organs see the mean — perfusion pressure from any blood pressure reading, held up against the 65 mmHg line.
How to read the result
Mean arterial pressure (mmHg) falls into these published bands.
A septic patient after initial fluids: blood pressure 85/50 mmHg.
MAP 62 mmHg — below target
Under the usual ≥ 65 mmHg perfusion target despite a systolic that can read as tolerable — grounds to escalate resuscitation, and in septic shock to weigh vasopressors, remembering that chronic hypertensives may need a higher target for the same organ perfusion.
Who this is for
For emergency, ICU, and anaesthetic staff resuscitating shock, titrating vasopressors, or judging whether a soft blood pressure is actually perfusing — MAP, not systolic, is the number the Surviving Sepsis Campaign target and most vasopressor protocols are written in, and this tool bands the estimate against it.
How it works
What it calculates
Mean arterial pressure — the perfusion pressure organs actually see — estimated as diastolic plus a third of the pulse pressure.
Interpreting the result
The common resuscitation target is a MAP of at least 65 mmHg (Surviving Sepsis Campaign); chronic hypertensives may need more for the same organ perfusion, and individual targets override the default.
Limitations
The formula assumes a normal heart-rate waveform — at marked tachycardia it underestimates; an arterial line measures rather than estimates when precision matters.
Built on published evidence
- Target ≥ 65 mmHg in septic shock; individual targets vary. Reference: Surviving Sepsis Campaign 2021
Codification last reviewed 2026-08-28, and checked against published reference values in automated tests on every release — see the full evidence ledger.
Questions clinicians ask
How is MAP calculated from a cuff pressure?
MAP = (SBP + 2 × DBP) / 3 — equivalently, diastolic plus a third of the pulse pressure. Diastolic is weighted double because the heart spends roughly two-thirds of each cycle in diastole at normal rates.
What MAP should I target in shock?
The common resuscitation target is at least 65 mmHg, per the Surviving Sepsis Campaign 2021. It is a default, not a law — chronic hypertensives may need more for the same organ perfusion, and individual targets override it.
Why MAP rather than the systolic pressure?
MAP is the perfusion pressure organs actually see across the cardiac cycle — a patient can hold a passable systolic while the mean, and therefore renal and cerebral perfusion, sits below target.
When is the formula unreliable?
It assumes a normal heart-rate waveform, so at marked tachycardia it underestimates the true mean. When precision matters — vasopressor titration in particular — an arterial line measures MAP rather than estimating it.
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