Shock Index calculator
Result
0.67
Normal range (0.6–1.0)
SI > 1.0 associated with 30-day mortality in trauma and sepsis. SI > 1.4: immediate resuscitation.
How to use it
- 1
Measure HR and SBP simultaneously. Use non-invasive cuff measurement. Ideally arterial line in critically ill.
- 2
Calculate HR ÷ SBP. Normal SI = 0.5–0.7. SI > 1.0 indicates the heart is working harder than pressure generated — early compensated shock.
- 3
Act on elevated SI. SI >1.0: IV access × 2, fluid challenge, blood cultures, consider early vasopressors.
When to use it
- Rapid triage in ED or pre-hospital
- Identifies haemodynamic instability faster than BP alone, especially in compensated shock where SBP is preserved.
- Trauma
- SI > 1.0 predicts massive transfusion protocol activation with good sensitivity.
- Sepsis screening
- SI > 1.0 with suspected infection supports early goal-directed therapy. Pairs well with qSOFA.
A reference for clinicians and students, not medical advice. A score supports a decision; it does not make one. Check every result against the patient in front of you and your local protocol.
At a glance
- Specialty
- Cardiology
- Inputs
- 2
- Type
- Formula
