In search of the optimal oxygen saturation for extremely low birth weight infants: a systematic review and meta-analysis.

BACKGROUND The optimal arterial oxygen saturation in the first weeks of life is unknown for immature newborn infants. OBJECTIVES To determine the effect of targeting high versus low oxygen saturation in the first weeks of life on the outcome of very low and extremely low birth weight infants. METHODS Randomized and observational studies were sought that compared the outcomes in babies with high or low oxygen saturation targeting assessed by pulse oximetry. RESULTS Ten studies were identified, of which 8 had severe retinopathy of prematurity (n = 3811) and 8 had bronchopulmonary dysplasia/lung problems (n = 4612) as outcomes. Two studies also provided survival data. The relative risk (RR) in favor of low SpO2 was 0.42 (95% CI 0.34-0.51) for severe retinopathy of prematurity, 0.73 (95% CI 0.63-0.86) for bronchopulmonary dysplasia/lung problems, and 1.12 (95% CI 0.86-1.45) for mortality. There was 1 randomized trial with retinopathy of prematurity, 3 with bronchopulmonary dysplasia/lung problems, and 1 with mortality as the outcome. When analyzing the randomized trial separately, the RR (95% CI) for severe retinopathy of prematurity was 0.48 (0.34-0.68), for bronchopulmonary dyslasia/lung problems it was 0.79 (0.64-0.97), and for mortality it was 1.27 (1.01-1.60). CONCLUSIONS A low oxygen saturation approach reduces severe retinopathy of prematurity by 50%, i.e., from 20.9 to 9.5%, and bronchopulmonary dysplasia/lung problems by 25%, i.e., from 40.8 to 29.7%. Further randomized trials are needed to provide definite conclusions and to assess whether reducing oxygen saturation has an impact on mortality among very and extremely low birth weight infants.