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Derivation and validation of an improved pediatric shock index for predicting need for early intervention and
Nathan Georgette1, Robert Keskey, David Hampton
1From the Section of Pediatric Emergency Medicine, Department of Pediatrics (N.G., A.M.), University of Chicago Medicine; Section of Pediatric Surgery, Department of Surgery (N.G., N.C., M.B.S.), University of Chicago Medicine; Section of Trauma Surgery, Department of Surgery (R.K., D.H., T.Z., K.W.), University of Chicago Medical Center, Chicago, Illinois; and Division of Trauma and Burn Surgery, Children's National Hospital (E.A., R.S.B.), Children's National Hospital, Washington, DC.
Insights
A new pediatric shock index (PSI) equation, based on age, improves early blood transfusion prediction in pediatric trauma compared to the standard age-adjusted shock index (SIPA). This enhanced tool aids in better patient outcomes.
Area of Science:
- Pediatric Trauma Care
- Medical Prognostics
- Epidemiology
Background:
- Pediatric age-adjusted shock index (SIPA) has limitations in precision due to fixed reference ranges.
- Hypothesis: A pediatric shock index (PSI) equation using age-based vital signs will outperform SIPA.
Purpose of the Study:
- To develop and validate a novel pediatric shock index (PSI) equation for improved accuracy in pediatric trauma.
- To compare the performance of PSI and a simplified rapid PSI (rPSI) against SIPA.
Main Methods:
- Retrospective analysis of 439,699 pediatric trauma patients (ages 1-12).
- Derivation of age-based shock index (SI) cutoffs using a training set.
- Validation of PSI and rPSI against SIPA for predicting early transfusion, mortality, and ICU admission.
Main Results:
- PSI and rPSI demonstrated higher positive predictive values for early transfusion than SIPA (8.3% and 6.3% vs. 4.3%).
- Negative predictive values for early transfusion were comparable across PSI, rPSI, and SIPA (all ~99.3-99.4%).
- PSI and rPSI showed improved prediction for early blood transfusion and mortality.
Conclusions:
- The derived PSI and rPSI equations offer improved prognostic capabilities in pediatric trauma.
- These novel indices provide more precise prediction of early transfusion needs and mortality compared to SIPA.
Background:
Shock index, pediatric age adjusted (SIPA), has been widely applied in pediatric trauma but has limited precision because of the reference ranges used in its derivation. We hypothesized that a pediatric shock index (PSI) equation based on age-based vital signs would outperform SIPA.
Methods:
A retrospective cohort of trauma patients aged 1 to 18 years from Trauma Quality Programs - Participant Use File 2010 to 2018 was performed. A random 70% training subset was used to derive Youden index-optimizing shock index (SI) cutoffs by age for blood transfusion within 4 hours. We used linear regression to derive equations representing the PSI cutoff for children 12 years or younger and 13 years or older. For children 13 years or older, the well-established SI of 0.9 remained optimal, consistent with SIPA and other indices. For children 12 years or younger in the 30% validation subset, we compared our age-based PSI to SIPA as predictors of early transfusion, mortality, pediatric intensive care unit admission, and injury severity score of ≥25. For bedside use, a simplified "rapid" pediatric shock index (rPSI) equation was also derived and compared with SIPA.
Results:
A total of 439,699 patients aged 1 to 12 years met the inclusion criteria with 2,718 (1.3% of those with available outcome data) requiring transfusion within 4 hours of presentation. In the validation set, positive predictive values for early transfusion were higher for PSI (8.3%; 95% confidence interval [CI], 7.5-9.1%) and rPSI (6.3%; 95% CI, 5.7-6.9%) than SIPA (4.3%; 95% CI, 3.9-4.7%). For early transfusion, negative predictive values for both PSI (99.3%; 95% CI, 99.2-99.3%) and rPSI (99.3%; 95% CI, 99.2-99.4%) were similar to SIPA (99.4%; 95% CI, 99.3-99.4%).
Conclusion:
We derived the PSI and rPSI for use in pediatric trauma using empiric, age-based SI cutoffs. The PSI and rPSI achieved higher positive predictive values and similar negative predictive values to SIPA in predicting the need for early blood transfusion and mortality.
Level Of Evidence:
Prognostic/Epidemiological; level III.
