Deriving shock index pediatric age-adjusted thresholds to predict need for emergent intervention

Background

Shock index (SI) has been used to identify patients at risk for severe injury and predict those who require an emergent intervention. In adults, SI > 0.9 is considered elevated. Shock index pediatric age-adjusted (SIPA) modifies this threshold based on patients’ age. This analysis leverages a large dataset to empirically identify threshold values of SI using a composite outcome capturing patients’ need for emergent intervention.

Methods

Pediatric patient data was abstracted from the Trauma Quality Improvement Program Participant Use Files from 2013 – 2020. 484,586 patients were included in the analysis. Area under the receiver-operator characteristic curve (AUROC) was used to empirically derive optimal cutoffs by age group. Need for emergent intervention included craniotomy, thoracotomy, laparotomy, chest tube, angioembolization, endotracheal intubation, and blood transfusion within 24 h of arrival or use of mechanical ventilation or admission to an intensive care unit.

Results

Empirically derived SIPA-E cutoffs (1.23, 1.05, 0.95, and 0.85 for ages 1–3, 4–6, 7–12, and 13–17 years, respectively) were similar to established SIPA-L cutoffs (1.22, 1.22, 1.00, and 0.90). Overall accuracy was consistent between the two cutoffs with nearly equal trades of sensitivity for specificity but remain low overall (empirical cutoff sensitivity = 33.8 %, specificity = 79.5 %; established cutoff sensitivity = 26.5 %, specificity = 86.8 %).

Conclusions

Empirically derived cutoffs agreed with established cutoffs for SIPA, but overall accuracy is low. Rather than predicting broad outcomes, SIPA seems better suited to narrow cases where it has shown greater accuracy, such as the need for urgent blood transfusion.

Level of evidence

Prognostic/epidemiological; Level III