Age-Modified Shock Index Calculator

Calculates age multiplied by the modified shock index. Includes field guidance, formula provenance, interpretation and Learn More content.

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Age-Modified Shock Index
Clinical Decision Tool

Calculates age multiplied by the modified shock index.

Use chronological age in years.
Use a contemporaneous heart rate.
Use measured or appropriately calculated MAP.
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Clinical Decision Support Only

MediCalc calculators are intended to support qualified healthcare professionals and must not replace professional clinical judgement. Do not enter patient-identifiable information into Saved Progress.

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MedicalC Knowledge Hub

Age-Modified Shock Index: Clinical Guide

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Calculates age multiplied by the modified shock index.

Overview

Calculates age multiplied by the modified shock index.

Clinical Significance

A research-derived haemodynamic risk marker. It should not delay resuscitation or replace assessment of perfusion and cause of shock.

How It Is Calculated

  • Age-MSI = age × heart rate / mean arterial pressure.

Interpretation

  • A research-derived haemodynamic risk marker. It should not delay resuscitation or replace assessment of perfusion and cause of shock.

Worked Example

Enter a clinically consistent set of values in the displayed units. MedicalC applies: Age-MSI = age × heart rate / mean arterial pressure.

Limitations

  • This tool does not establish a diagnosis or mandate treatment.
  • Published cut-offs may vary between cohorts and measurement methods.
  • Calculation precision cannot compensate for poor source data.

Clinical Pearls

  • Trend the result over time where clinically appropriate.
  • Record the source values and units alongside the calculated result.

Common Mistakes

  • Using the wrong unit.
  • Combining measurements obtained at different times.
  • Applying a research-derived threshold as a universal treatment trigger.

Frequently Asked Questions

What does this calculator provide?

Calculates age multiplied by the modified shock index.

Can this result be used alone?

No. It must be interpreted with clinical context and appropriate investigations.

What equation is used?

Age-MSI = age × heart rate / mean arterial pressure.

What is the main limitation?

The result depends on valid inputs and may not be calibrated for every population or setting.

References

  1. Observational emergency and trauma literature on age-modified shock index. — Formula, physiological or validation reference.

Reviewed by: MedicalC Clinical Editorial Team
Last reviewed: July 2026

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Reviewed by: MedicalC Clinical Editorial Team Last reviewed: July 2026

Clinical Disclaimer

MedicalC calculators and clinical tools are intended to support healthcare professionals. They do not replace clinical judgement, individual patient assessment, local guidance or specialist advice.

Results should always be interpreted in the context of the patient’s history, examination, investigations, current clinical condition and applicable professional guidance.

Reviewed by: MedicalC Clinical Editorial Team Last reviewed: July 2026
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