Category: Pediatrics
Keywords: SI, hypotension, trauma, shock (PubMed Search)
Posted: 2/20/2025 by Jenny Guyther, MD
(Updated: 2/21/2025)
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This was a retrospective cohort study of the national trauma data bank that included about 64000 pediatric trauma patients in the derivation group and the same amount in the validation group. The authors empirically created upper and lower cut off values for the shock index based on age. They compared the shock index based on age cut offs with major trauma as defined by the standardized triage assessment tool criteria.
The empirically derived age adjusted values had a sensitivity of 43.2% and a specificity of 79.4% for major trauma. The sensitivity of the pediatric shock index (PSI) in that same group was 33.9% with a specificity of 90.7%. The pediatric-adjusted shock index (SIPA) had a 37.4% sensitivity and 87.8% sensitivity for 4-16 year olds.
Shock index = (Heart Rate / Systolic BP)
Pediatric Shock Index (PSI)
For children age 1-12 years
SI > 1.55 - (0.5) x (age in years)
Patients with an elevated shock index had a 5.02 greater odds of major trauma in this study.
This study used age specific cut offs such as:
1 yr to < 3 years = lower limit of 0.73 and an upper limit of 1.40
(see article for a full table).
Patients with a shock index below the lower limit had a 1.55 greater offs of major trauma and patients with a shock index above the upper limit had a 3.97 greater risk of major trauma.
Bottom line: Shock index alone has a limited role in the identification of major trauma in children. Of these three methods for calculating/interpreting shock index, PSI seemed to do better.
Ramgopal S, Gorski JK, Chaudhari PP, Spurrier RG, Horvat CM, Macy ML, Cash RE, Stey AM, Martin-Gill C. Establishing thresholds for shock index in children to identify major trauma. Injury. 2024 Aug 23:111840. doi: 10.1016/j.injury.2024.111840. Epub ahead of print. PMID: 39198074.
