Lactate, Base Excess, and the Pediatric Index of Mortality: Exploratory Study of an International, Multicenter

Kevin P Morris1,2, Melpo Kapetanstrataki3, Barry Wilkins4

  • 1Paediatric Intensive Care Unit, Birmingham Children's Hospital, Birmingham, United Kingdom.

Insights

Blood lactate levels at pediatric intensive care unit (PICU) admission are a stronger predictor of mortality than base excess. Incorporating lactate into the Pediatric Index of Mortality may slightly improve its performance in predicting outcomes.

Area of Science:

  • Pediatric Critical Care Medicine
  • Biomarkers in Critical Illness
  • Healthcare Analytics

Background:

  • Pediatric Index of Mortality (PIM) is a widely used scoring system for predicting mortality in pediatric intensive care units (PICUs).
  • Blood lactate and base excess are established physiological markers of critical illness and tissue hypoperfusion.
  • The predictive value of these markers, particularly lactate, for mortality and their potential integration into existing scoring systems requires further investigation.

Purpose of the Study:

  • To examine the association between ICU admission blood lactate and base excess with ICU mortality.
  • To evaluate the impact of including blood lactate in the Pediatric Index of Mortality (PIM) scoring system.

Main Methods:

  • A retrospective cohort study utilizing prospectively collected data from the U.K. Pediatric Intensive Care Audit Network and the Australia and New Zealand Pediatric Intensive Care Registry.
  • Analysis included over 123,000 PICU admissions between 2012 and 2015.
  • Statistical methods assessed the relationship between lactate, base excess, and mortality, and evaluated model performance with and without these biomarkers.

Main Results:

  • Children with recorded lactate levels exhibited higher illness severity, increased need for ventilation, and greater mortality risk compared to those without (p < 0.001).
  • Blood lactate demonstrated a stronger association with mortality (OR, 1.32) than absolute base excess (OR, 1.13).
  • Incorporating lactate into the PIM score showed a modest performance improvement, with combined lactate and base excess yielding the best predictive performance.

Conclusions:

  • Blood lactate at PICU admission is a more potent predictor of mortality than base excess.
  • Adding lactate to the PIM model offers a potential, albeit small, improvement in predictive accuracy.
  • The clinical utility of enhancing the PIM score must be weighed against the increased data collection burden.
Abstract