Purpose: To determine the incidence of retinopathy of prematurity (ROP) over a 2-year period before and after a change in the practice of oxygen supplementation.
Design: Nonrandomized, retrospective study.
Participants: All infants in a single Level III neonatal intensive care unit between the years of 2005 and 2007.
Methods: A prospective database recorded the gestational age, birth weight, stage and zone of ROP, threshold disease, treatment, final outcome and date of examination, maternal and infant demographics, and neonatal intensive care unit course. Year 1 (August 1, 2005 to July 31, 2006) includes a patient cohort who received the standard oxygen supplementation protocol, which has oxygen targets of 95% to 100% saturation. Year 2 (August 1, 2006 to July 31, 2007) includes a patient cohort who has strictly monitored oxygen targets of <34 weeks corrected gestational age oxygen limits of 80% to 95% and target 85% to 92% oxygen saturation and >34 weeks corrected gestational age limits of 85% to 100% and target 92% to 97% saturation.
Main outcome measure: Incidence of ROP in year 1 before a change in oxygen protocol compared with the incidence of ROP in year 2 after a change in the oxygen protocol.
Results: A total of 114 children in year 1 and 108 children in year 2 were identified as having been born or transferred to the Fairview Nursery. Ninety-eight infants were examined before and 92 infants were examined after the change in oxygen standards, comprising 190 consecutive patients examined between September 2005 and October 2007. ROP was present in 35% of infants in group 1 before the change in oxygen protocol compared with 13% after the change in oxygen standards (P=0.001); stage 3 decreased from 11% to 2% (P=0.021); threshold disease decreased from 7% to 1% (P=0.066). Stage 0 (immature vessels, no ROP) incidence increased (pre/post-oxygen change 30%/51% stage 0, P=0.001). There were statistically significant differences in mode of delivery (P=0.007), sepsis <3 days of life (P=0.01), and oxygen at discharge (P=0.003).
Conclusions: Lower oxygen targets at early gestational age and higher oxygen targets at older gestational age decrease the severity and incidence of ROP while inducing normal retinal development.