Optimal oxygenation of extremely low birth weight infants: a meta-analysis and systematic review of the oxygen saturation target studies.

BACKGROUND The optimal oxygen saturation for extremely low birth weight infants in the postnatal period beyond the delivery room is not known. OBJECTIVES To summarize and discuss the results of the randomized trials, constituting the NEOPROM (Neonatal Oxygenation Prospective Meta-analysis) collaborative study, examining the effect of low versus high functional oxygen saturation targets in the postnatal period in premature infants with gestational age <28 weeks. METHODS A meta-analysis of SUPPORT (Surfactant, Positive Pressure and Pulse Oximetry Randomized Trial), the three BOOST II (Benefits of Oxygen Saturation Targeting) studies and the COT (Canadian Oxygen Trial) was performed including a total of 4,911 infants randomized to either a low (85-89%) or high (91-95%) functional oxygen saturation (SpO2) within the first 24 h after birth. RESULTS Relative risks (RR; 95% CIs) comparing a low versus a high oxygen saturation target were 1.41 (1.14-1.74) for mortality at discharge or at follow-up, 0.74 (0.59-0.92) for severe retinopathy of prematurity, 0.95 (0.86-1.04) for physiologic bronchopulmonary dysplasia, 1.25 (1.05-1.49) for necrotizing enterocolitis, 1.02 (0.88-1.19) for brain injury, and 1.01 (0.95-1.08) for patent ductus arteriosus. RR >1.0 favors a high oxygen saturation. CONCLUSIONS RRs for mortality and necrotizing enterocolitis are significantly increased and severe retinopathy of prematurity significantly reduced in low compared to high oxygen saturation target infants. There are no differences regarding physiologic bronchopulmonary dysplasia, brain injury or patent ductus arteriosus between the groups. Based on these results, it is suggested that functional SpO2 should be targeted at 90-95% in infants with gestational age <28 weeks until 36 weeks' postmenstrual age. However, there are still several unanswered questions in this field.