Comparison of age-adjusted shock indices as predictors of injury severity in paediatric trauma patients immediately after emergency department triage: A report from the Korean multicentre registry.

INTRODUCTION: Shock index paediatric-adjusted (SIPA) was presented for early prediction of mortality and trauma team activation in paediatric trauma patients. However, the derived cut-offs of normal vital signs were based on old references. We established alternative SIPAs based on the other commonly used references and compared their predictive values. METHODS: We performed a retrospective review of all paediatric trauma patients aged 1-15 years in the Emergency Department (ED)-based Injury In-depth Surveillance (EDIIS) database from January 1, 2011 to December 31, 2019. A total of 4 types of SIPA values were obtained based on the references as follows: uSIPA based on the Nelson textbook of paediatrics 21st ed., SIATLS based on the ATLS 10th guideline, SIPALS based on the PALS 2020 guideline, and SIPA. In each SIPA group, the cut-off was established by dividing the group into 4 subgroups: toddler (age 1-3), preschooler (age 4-6), schooler (age 7-12), and teenager (age 13-15). We performed an ROC analysis and calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) to compare the predicted values of each SIPA in mortality, ICU admission, and emergent surgery or intervention. RESULTS: A total of 332,271 patients were included. The proportion of patients with an elevated shock index was 14.9 % (n = 49,347) in SIPA, 22.8 % (n = 75,850) in uSIPA, 0.3 % (n = 1058) in SIATLS, and 4.3 % (n = 14,168) in SIPALS. For mortality, uSIPA achieved the highest sensitivity (57.0 %; 95 % confidence interval 56.9 %-57.2 %) compared to SIPA (49.4 %, 95 % CI 49.2 %-49.5 %), SIATLS (25.5 %, 95 % CI 25.4 %-25.7 %), and SIPALS (43.8 %, 95 % CI 43.7 %-44.0 %), but there were no significant differences in the negative predictive value (NPV) or area under the curve (AUC). The positive predictive value (PPV) was highest in SIATLS (5.7 %, 95 % CI 5.6 %-5.8 %) compared to SIPA (0.2 %, 95 % CI 0.2 %-0.3 %), uSIPA (0.2 %, 95 % CI 0.2 %-0.2 %), and SIPALS (0.7 %, 95 % CI 0.7 %-0.8 %). The same findings were presented in ICU admission and emergent operation or intervention. CONCLUSION: The ATLS-based shock index achieved the highest PPV and specificity compared to SIPA, uSIPA, and SIPALS for adverse outcomes in paediatric trauma.