# PIM2, lactate, and trauma score to predict mortality in critically ill pediatric trauma patients

## TL;DR

This study assesses how well PIM2, lactate levels, and PTS predict mortality in critically ill pediatric trauma patients in Brazil.

## Contribution

The study evaluates the combined predictive power of PIM2, lactate, and PTS in a large Brazilian PICU trauma cohort.

## Key findings

- PIM2 had the highest AUC (0.93) for predicting mortality compared to lactate (0.86) and PTS (0.82).
- PIM2 and lactate remained significant predictors of mortality in multivariable analysis.
- PTS provided limited additional predictive value once patients were in the PICU.

## Abstract

To evaluate the prognostic performance of the Pediatric Index of Mortality 2 (PIM2), serum lactate, and Pediatric Trauma Score (PTS) for mortality in a large case series of critically ill pediatric trauma patients admitted to a specialized PICU in Brazil.

Retrospective case series conducted in the Pediatric Intensive Care Unit of a tertiary trauma hospital in Brazil. All trauma patients aged 1 month to 18 years admitted between March 2018 and March 2025 and hospitalized for >24 h were eligible (n = 1495). Demographic, clinical, and laboratory data were collected, including PIM2, initial lactate, and PTS. The primary outcome was all-cause PICU mortality.

Death occurred in 1.5% of patients. ROC curve analysis was performed in 620 patients with complete data for the three markers. Areas under the curve (AUCs) were: PIM2, 0.93 (95% CI, 0.91–0.95); lactate, 0.86 (95% CI, 0.83–0.88); and PTS, 0.82 (95% CI, 0.79–0.85). In univariable logistic regression, all markers were independently associated with mortality. A 10-fold increase in PIM2 and lactate raised death odds by 36-fold and 226-fold, respectively, while each point increase in PTS reduced odds by 34.6%. In the multivariable model, PIM2 and lactate remained significant predictors.

PIM2 and lactate remained independently associated with mortality after mutual adjustment in pediatric trauma patients admitted to a specialized PICU. PTS, while valuable for prehospital triage, added little once intensive care was initiated.