Modified Shock Index (MSI)
MSI = Heart Rate / Mean Arterial Pressure. More sensitive than standard shock index for detecting haemodynamic instability in trauma, sepsis, and haemorrhage.
Score interpretation
MSI below 0.7 was associated with higher mortality in one single-centre retrospective ED study (Liu 2012).
→ Interpret with the clinical picture (e.g. hypertension, bradycardia); not a validated grade.
MSI 0.7–1.3: the reference range in one single-centre retrospective ED study (Liu 2012).
→ Does not exclude shock — reassess with any clinical change.
MSI above 1.3 was associated with higher mortality in one single-centre retrospective ED study (Liu 2012).
→ Assess for shock and its cause; resuscitate and escalate as the clinical picture requires.
Interpretation bands for the Modified Shock Index. Apply clinical judgement and local guidance.
References
- Liu YC, Liu JH, Fang ZA, et al. Modified shock index and mortality rate of emergency patients. World J Emerg Med. 2012;3(2):114–117.
Related
Curated clinical cross-links plus same-class fallbacks.
- Hydrocortisone (ICU — Stress Dosing) · Corticosteroid (ICU/Septic Shock)
- Tranexamic Acid (ICU/Trauma/Surgical) · Antifibrinolytic
- Noradrenaline (Cardiogenic Shock / Vasopressor) · Vasopressor / Cardiogenic Shock
- Vasopressin / Terlipressin · Vasopressin Analogue — Vasodilatory Shock / Variceal Bleeding
- Hydrocortisone (Oral Replacement) · Glucocorticoid Replacement
- Morphine (Oral) · Strong Opioid Analgesic — Step 3 WHO Ladder
- Acute Heart Failure · ESC 2021 Heart Failure Guidelines; NICE NG106
- NSTEMI / Unstable Angina · ESC 2020 NSTEMI Guidelines; NICE NG185
- New-Onset Atrial Fibrillation · ESC 2020 AF Guidelines; NICE NG196
- Hypertensive Emergency · ESC/ESH 2018 Hypertension Guidelines; NICE NG136
- Bradycardia Management · Resuscitation Council UK ABCDE; ESC 2021 Pacing Guidelines
- Ventricular Tachycardia / Fibrillation · Resuscitation Council UK ACLS; ESC 2022 Ventricular Arrhythmia Guidelines
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.