Oxygen saturation in premature infants at risk for threshold retinopathy of prematurity.

We aimed to determine if oxygen saturation, desaturations, and saturation variability play a role in progression of retinopathy of prematurity (ROP) and need for laser treatment. This was a retrospective case-control study. We performed chart review of premature infants in a university hospital neonatal intensive care unit consecutively examined for ROP between May 2000 and December 2001. We compared birthweight, postmenstrual age, and oxygen saturation for 3 weeks before laser treatment for threshold ROP in group 1 (n=19) (average weight at treatment 2508 grams) and group 2 (n=18) before they reached 2500 grams. Outcome measures were retinopathy progression and need for treatment. Adjusting for birthweight and postmenstrual age, known predictors of ROP progression, we found that babies requiring laser treatment (group 1) had lower average daily oxygen saturation levels in the study period, significantly on 5/20 days (25%). These babies had saturations below 95% on 18/20 days (90%). Babies not requiring laser (group 2) had saturations below 95% on 2/20 days (10%). The last day on which pretreatment saturations differed significantly was 2 days before laser. Group 1 had more desaturations below 80% (6.0±3.2) than group 2 (3.2±1.2), p=0.0002 (independent samples t tests). Saturations varied more for individual group 1 infants. Decreased oxygen saturation as early as 3 weeks and as late as 2 days before laser, increased number of desaturations, and saturation variability were seen in babies eventually requiring laser treatment for ROP.