Table 1.

Variations of shock index

Shock index (SI) name variation	Equation	Notes
SI	HR/SBP
Modified SI (MSI)	HR/MAP	MAP substituted for SBP
Age SI	Age × (HR/SBP)	SI multiplied by patient’s age
Shock Index Pediatric Adjusted (SIPA)	(HR/SBP)	Formula for SI is the same. Cutoffs are different for each age group: Ages 4–6: >1.22 Ages 7–12: >1.0 Ages 13–16: >0.9

Abbreviations: HR, heart rate; MAP, mean arterial pressure; SBP, systolic bood pressure.