Hyperoxia in pediatric severe traumatic brain injury (TBI): a comparison of patient classification by cutoff versus cumulative (area-under-the-curve) analysis.

Objective: Hyperoxia is associated with adverse outcome in severe traumatic brain injury (TBI). This study explored differences in patient classification of oxygen exposure by PaO ₂ cutoff and cumulative area-under-the-curve (AUC) analysis.
Methods: Retrospective, explorative study including children (<18 years) with accidental severe TBI (2002-2015). Oxygen exposure analysis used three PaO ₂ cutoff values and four PaO ₂ AUC categories during the first 24 hours of Pediatric Intensive Care Unit (PICU) admission.
Results: Seventy-one patients were included (median age 8.9 years [IQR 4.6-12.9]), mortality 18.3% (n = 13). Patient hyperoxia classification differed depending on PaO ₂ cutoff vs AUC analysis: 52% vs. 26%, respectively, were classified in the highest hyperoxia category. Eleven patients (17%) classified as 'intermediate oxygen exposure' based on cumulative PaO ₂ analysis whereby they did not exceed the 200 mmHg PaO2 cutoff threshold. Patient classification variability was reflected by Pearson correlation coefficient of 0.40 ( p -value 0.001).
Conclusions: Hyperoxia classification in pediatric severe TBI during the first 24 hours of PICU admission differed depending on PaO ₂ cutoff or cumulative AUC analysis. We consider PaO ₂ cumulative (AUC) better approximates (patho-)physiological circumstances due to its time- and dose-dependent approach. Prospective studies exploring the association between cumulative PaO ₂ , physiological parameters (e.g. ICP, PbtO ₂ ) and outcome are warranted as different patient classifications of oxygen exposure influences how its relationship to outcome is interpreted.