Table 3.

Shock index summary

Population	SI variation studied	SI value	Comparator	Outcomes studied	Comments and Limitations
Triage	SI MSI Age SI	0.5–0.7 >0.7 >1.0 >1.2	SBP	Inpatient mortality ICU admission Hospital admission	SI, MSI, and age SI better at predicting inpatient mortality than SBP, but not ICU admission SI had poor sensitivity and specificity at predicting mortality
Trauma	SI MSI Age SI	<0.7 >0.7 >0.9 >1.0 ≥1 1.2 >1.3	ABC score DBP HR SBP RTS REMS	Death: ED Within 24 hrs Hospital Need for MTP Transfusion >2 units PRBCs ISS: >15 ≥16 Emergent operation >1-day ICU LOS	SI >0.9 correlates with increased need for MTP SI ≥1 performs similarly to ABC Score in predicting need for MTP SI>1.0 performed similarly to SBP<90 MSI may be more accurate predictor of mortality in trauma patients than SI, HR, SBP, or DBP alone
Obstetrics	SI	>0.7 >0.85	HR SBP	Ruptured ectopic pregnancy	SI consistently higher in ruptured ectopic pregnancy compared to un-ruptured ectopic pregnancy SI >0.7 was the most sensitive, SI >0.85 most specific Only obstetrical condition studied was ectopic pregnancy
Sepsis	SI	>0.7 >1	CVP SIRS SIRS without WBC	Hyperlactatemia 28-day mortality Increase in CI as determined by ECHO	High NPV with normal SI for lactate <4 mmol/L Poor PPV of hyperlactatemia and mortality for SI and SIRS Low SI and high CVP unlikely to improve CI with additional fluid boluses
Cardiovascular Disease	SI	>0.8 >1	sPESI RV dysfunction on ECHO	In-hospital mortality in STEMI patients 30-day mortality In-hospital mortality	PESI preferred to SI Low-quality studies
Pediatrics	SIPA	Age-based cutoffs	SI HR SBP DBP Age-adjusted hypotension	Blunt liver/spleen injury ISS>24 Blood transfusion Operation ICU admission Death: In-hospital mortality 48-hr mortality Mechanical ventilation ICU LOS	Higher sensitivities and specificities compared to other markers/indicators
Geriatrics	SI	>1	Age SI MSI HR SBP	In-hospital mortality 30-day mortality	Lower sensitivity and higher specificity Chronic conditions may limit applicability of SI in this population

Abbreviations: CI, cardiac index; CVP, central venous pressure; HR, heart rate; ICU, Intensive Care Unit; MSI, modified shock index; NPV, negative predictive value; PPV, positive predictive value; REMS, Rapid Emergency Medicine Score; RTS, Revised Trauma Score; RV, Right ventricle; SI, shock index; sPESI, simplified pulmonary embolism severity index; SBP, systolic blood pressure.