Shock Index

Shock Index: A simple ratio (HR/SBP) to detect occult shock when vital signs appear deceptively normal.

Heart Rate (bpm)

Systolic BP (mmHg)

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

Last Comprehensive Review: 2026-07-17

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

The Shock Index (SI) is a simple, bedside ratio of heart rate to systolic blood pressure. It is used to identify "occult shock"—patients who maintain a normal blood pressure through compensatory mechanisms but are at high risk for clinical deterioration and massive hemorrhage.

Normal SI is 0.5 - 0.7. An SI ≥ 0.9 is a common clinical threshold for increased mortality risk and the need for aggressive intervention.

Scoring Variables & Classification

Shock Index (SI) = Heart Rate (HR) / Systolic Blood Pressure (SBP)

SI Value	Clinical Status	Risk Level
0.5 - 0.7	Normal	Low
0.7 - 0.9	Borderline / Compensating	Intermediate
0.9 - 1.1	Occult Shock	High
> 1.1	Decompensated Shock	Critical
> 1.3	Exsanguination Risk	Extreme

Last Comprehensive Review: 2026-07-17

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Shock Index

When to Use

How it Works

Clinical Pearls

Next Steps

The Evidence

Origins & History

When to Use

Scoring Variables & Classification

Clinical Pearls

Management & Clinical Actions

The Evidence

The shock index.

The shock index as a predictor for salvage in the emergency department.

The Shock Index—an early predictor for hypovolemic shock and need for massive transfusion.

Related Tools

Recent Journal Updates

Shock Index

When to Use

How it Works

Clinical Pearls

Next Steps

The Evidence

Origins & History

When to Use

Scoring Variables & Classification

Clinical Pearls

Management & Clinical Actions

The Evidence

The shock index.

The shock index as a predictor for salvage in the emergency department.

The Shock Index—an early predictor for hypovolemic shock and need for massive transfusion.

Related Tools

Recent Journal Updates