Association of Hyperoxia During Cardiopulmonary Bypass and Postoperative Delirium in the Pediatric Cardiac ICU

Abstract

OBJECTIVE: ICU delirium commonly complicates critical illness associated with factors such as cardiopulmonary bypass (CPB) time and the requirement of mechanical ventilation (MV). Recent reports associate hyperoxia with poorer outcomes in critically ill children. This study sought to determine whether hyperoxia on CPB in pediatric patients was associated with a higher prevalence of postoperative delirium. DESIGN: Secondary analysis of data obtained from a prospective cohort study. SETTING: Twenty-two-bed pediatric cardiac ICU in a tertiary children’s hospital. PATIENTS: All patients (18 yr old or older) admitted post-CPB, with documented delirium assessment scores using the Preschool/Pediatric Confusion Assessment Method for the ICU and who were enrolled in the Precision Medicine in Pediatric Cardiology Cohort from February 2021 to November 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 148 patients, who underwent cardiac surgery, 35 had delirium within the first 72 hours (24%). There was no association between hyperoxia on CPB and postoperative delirium for all definitions of hyperoxia, including hyperoxic area under the curve above 5 predetermined Pao 2 levels: 150 mm Hg (odds ratio [95% CI]: 1.176 [0.605–2.286], p = 0.633); 175 mm Hg (OR 1.177 [95% CI, 0.668–2.075], p = 0.572); 200 mm Hg (OR 1.235 [95% CI, 0.752–2.026], p = 0.405); 250 mm Hg (OR 1.204 [95% CI, 0.859–1.688], p = 0.281), 300 mm Hg (OR 1.178 [95% CI, 0.918–1.511], p = 0.199). In an additional exploratory analysis, comparing patients with delirium within 72 hours versus those without, only the z score for weight differed (mean [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%), MV days, severity of illness (Pediatric Index of Mortality 3 Score) score, CPB time, and z score for weight were associated with delirium (p < 0.05). CONCLUSIONS: Postoperative delirium (72 hr from CPB) occurred in 24% of pediatric patients. Hyperoxia, defined in multiple ways, was not associated with delirium. On exploratory analysis, nutritional status (z score for weight) may be a significant factor in delirium risk. Further delineation of risk factors for postoperative delirium versus ICU delirium warrants additional study.