MAP / Pulse Pressure / Shock Index
Compute four bedside hemodynamic indices from a single set of vitals: mean arterial pressure (MAP = DBP + (SBP - DBP)/3), pulse pressure (SBP - DBP), shock index (HR / SBP), and modified shock index (HR / MAP).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Systolic BP
- 120 mmHg
- Diastolic BP
- 80 mmHg
- Heart rate
- 110 bpm
Result: MAP 93.3; PP 40; shock index 0.92; modified shock index 1.18.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Systolic BP
- Diastolic BP
- Heart rate
What this is
Each index has a published reference range Sophie Well displays alongside the result: MAP target >=65 mmHg for organ perfusion, shock index >=1.0 as the classic occult-hypoperfusion threshold, modified shock index >=1.3 as a stronger predictor of transfusion need in trauma and sepsis.
When to use it
Use this at the bedside or chart review when a single blood-pressure number doesn't tell the whole story - tachycardia with a normal-looking systolic, a narrowing pulse pressure that suggests early shock, or a stable MAP masking compensated bleeding. The shock index in particular catches occult hypoperfusion that triage scores miss: a heart rate of 110 with a systolic of 105 looks acceptable in isolation but yields a shock index of 1.05, which has been associated with higher transfusion and mortality risk in trauma, postpartum hemorrhage, and severe sepsis. Reference math only; treat the patient, not the index.
How this is calculated
Allgower M, Burri C. Schockindex. Dtsch Med Wochenschr. 1967;92(43):1947-1950. Standard physiology for MAP and PP. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
More in Triage and acuity.