Early Hyperoxemia and Outcome Among Critically Ill Children

Abstract

Objective: 

To identify whether a high Pao₂ (hyperoxemia) at the time of presentation to the PICU is associated with in-hospital mortality.

Design: 

Single-center observational study.

Setting: 

Quaternary-care PICU.

Patients: 

Encounters admitted between January 1, 2009, and December 31, 2018.

Interventions: 

None.

Measurements and Main Results: 

Encounters with a measured Pao₂ were included. To account for severity of illness upon presentation, we calculated a modified Pediatric Risk of Mortality IV score excluding Pao₂ for each encounter, calibrated for institutional data. Logistic regression was used to determine whether hyperoxemia (Pao₂ ≥ 300 torr [39.99 kPa]) in the 12 hours surrounding PICU admission was associated with in-hospital mortality. We reperformed our analysis using a cutoff for hyperoxemia obtained by comparisons of observed versus predicted mortality when encounters were classified by highest Pao₂ in 50 torr (6.67 kPa) bins. Results are reported as adjusted odds ratios with 95% CIs. Of 23,719 encounters, 4,093 had a Pao₂ recorded in the period –6 to +6 hours after admission. Two hundred seventy-four of 4,093 (6.7%) had in-hospital mortality. The prevalence of hyperoxemia increased with rising modified Pediatric Risk of Mortality IV and was not associated with mortality in multivariable models (adjusted odds ratio, 1.38; 95% CI, 0.98–1.93). When using a higher cutoff of hyperoxemia derived from comparison of observed versus predicted rates of mortality of greater than or equal to 550 torr (73.32 kPa), hyperoxemia was associated with mortality (adjusted odds ratio, 2.78; 95% CI, 2.54–3.05).

Conclusions: 

A conventional threshold for hyperoxemia at presentation to the PICU was not associated with in-hospital mortality in a model using a calibrated acuity score. Extreme states of hyperoxemia (≥ 73.32 kPa) were significantly associated with in-hospital mortality. Prospective research is required to identify if hyperoxemia before and/or after PICU admission contributes to poor outcomes.