(777) Does Hyperoxia on Bypass Increase the Risk of Delirium in Children With Congenital Heart Disease?

Introduction: Nearly half of children with congenital heart disease who undergo cardiopulmonary bypass (CPB) develop delirium. Hyperoxia on CPB is associated with post-operative delirium in adults but remains unstudied in children. We tested the hypothesis that hyperoxia on CPB is associated with post-operative delirium in children via an exploratory analysis.

Methods: We retrospectively analyzed patients (age < 18yr) admitted to a cardiac ICU in a tertiary care children’s hospital post-operatively with documented Pediatric Confusion Assessment Method scores from Feb-Nov 2021. The primary outcome was occurrence of delirium in the first 72 hours of admission. Differences in baseline characteristics and exposures were assessed and the association between hyperoxia on CPB and postoperative delirium using logistic regression. Definitions of hyperoxia included paO2 (partial pressure of arterial oxygen) maximum, median, SD, hyperoxic Area Under the Curve (AUC) quartiles above 5 pre-determined paO2 levels (150, 175, 200, 250, 300), and AUC as a continuous measure.

Results: Of 148 patients, 35 had delirium within the first 72 hours (24%). Z-score for weight was lower in the delirium group (median [SD]: 0.09 [1.41] vs -0.48 [1.82], p< 0.05). When comparing patients who developed delirium at any point during their ICU stay (n=45, 30%), mechanical ventilation days, severity of illness (PIM3) score, CPB time, and z-score for weight were associated with delirium (p < 0.05). The median [IQR] paO2 on CPB for all patients was hyperoxic at 233[187, 280]. For all definitions of hyperoxia, there was no association with delirium occurrence within 72 hours or for delirium within the entire hospitalization.

Conclusions: In this single center cohort, hyperoxia on CPB had no association with development of delirium within 72 hours. However, nearly all patients were hyperoxic on CPB. Z-score for weight was associated with delirium, a new and potentially modifiable finding. Future studies could control for hyperoxia vs normoxia on CPB to further evaluate the risk of hyperoxia and development of delirium.