Supplementary Material for: Intermediate versus High Oxygen Saturation Targets in Preterm Infants: A National Cohort Study

Introduction: Optimal oxygen saturation targets remain unknown for extremely preterm infants.
Methods: Cohort analysis of eligible preterm infants born <29 weeks’ gestation admitted between 2011 and 2018 to centers submitting data to the Canadian Neonatal Network (CNN) database. Site questionnaires to determine saturation targets, alarm settings and date of change, allowed assignation of centers to intermediate (88-93%) or high (90-95%) saturation targets. A six-month washout period was applied to sites which switched targets during the study period. Our primary outcome was survival free of major morbidity. Secondary outcomes were death, necrotizing enterocolitis (NEC), bronchopulmonary dysplasia (BPD), treated retinopathy of prematurity (ROP) and evidence of brain injury during admission. Generalized estimating equations were applied to compensate for demographic differences and site practices.
Results: There were 2739 infants in the high (mean gestational age (GA) 26 ± 1.6 weeks) and 6813 infants in the intermediate (mean GA 26.2 ± 1.6 weeks) saturation target group. Survival without morbidity was higher in the intermediate target group (adjusted odds ratio (aOR): 1.58; 95% CI 1.04, 2.45). There was no difference in mortality between groups (aOR 0.81; 95% CI: 0.59, 1.11), in NEC, treated retinopathy, or brain injury. On subgroup analysis, restricting data to sites which switched targets during the study, intermediate saturation targets were associated with lower rates of BPD (aOR 0.45; 95% CI 0.28, 0.72).
Conclusions: For neonates <29 weeks’ gestation, intermediate saturation target was associated with a higher odds of survival without major morbidity compared to higher oxygen saturation target.