Shock Index Calculator
Enter heart rate and systolic blood pressure to calculate shock index and assess hemodynamic stability.
Use the Shock Index Calculator
Vital Sign Inputs
Formula Reference
Thresholds: <0.6 Normal • 0.6–0.9 Mildly elevated • 0.9–1.3 Elevated • >1.3 Severely elevated. For clinical use only; not a substitute for professional medical judgment.
Summary
The shock index (SI) is calculated by dividing heart rate by systolic blood pressure. It is a simple bedside tool used in emergency and critical care medicine to identify hemodynamic instability that may not be apparent from individual vital signs alone. A shock index above 1.0 is a recognized marker of significant physiologic stress and is associated with increased risk of adverse outcomes in trauma, sepsis, and hemorrhagic emergencies.
How it works
- Enter the patient's heart rate in beats per minute (bpm).
- Enter the systolic blood pressure in mmHg.
- The shock index is calculated as heart rate divided by systolic blood pressure.
- Results are categorized: normal (<0.6), mildly elevated (0.6–0.9), elevated (0.9–1.3), severely elevated (>1.3).
- The modified shock index (heart rate divided by mean arterial pressure) is also shown for reference.
Use cases
- Rapid triage of trauma patients in the emergency department.
- Monitoring hemodynamic status in patients with suspected sepsis.
- Early detection of occult shock in patients with normal blood pressure.
- Assessing response to fluid resuscitation over serial measurements.
- Perioperative monitoring of patients at risk for hemodynamic instability.
- Evaluating severity of hemorrhage in obstetric emergencies.