Clinical research, conducted at the Stead Family Department of Paediatrics, University of Iowa, Iowa City, USA, has demonstrated that a supplemental oxygen protocol is successful in halting the progression of retinopathy-of-prematurity (ROP) in premature infants from stage 2 to stage 3, without a corresponding increase in pulmonary morbidity. The study indicates that an appropriately implemented oxygen therapy procedure may provide signifcant benefit in inhibiting progression of stage 2 ROP. If reprodubile and sutiable for application in paediatric care facilities, the approach has the potential to decrease the risk of lifelong visual loss in the preterm infant population.
Preterm infants, especially those with a low birth weight, are at a realtively higher risk of ROP. As the lungs are under-developed, circulating oxygen is compromised impacting the vasucularisation of the developing retina which is sensitive to the amount of natural or artificially introduced oxygen. In the “Supplemental Therapeutic Oxygen for Prethreshold Retinopathy of Prematurity” trial (STOP-ROP), a decrease in progression of ROP with the use of higher oxygen saturation levels was indicated but not globally accepted for implementation in infants with stage 2 or higher ROP. To build on the previous research the Iowa team used targeted oxygen therapy on infants with stage 2 or greater ROP in order to compare the rates of progression of ROP in infants with stage 2 ROP before and after 2008, when the targeted oxygen therapy protocol was initiated, and to compare pulmonary outcomes between the two groups.
A retrospective cohort study compared infants undergoing ROP screening before (cohort A) and after (cohort B) implementation of an oxygen therapy protocol. The results indicated that in cohort A, without oxygen therapy protocol (between the years 2002–2007), 54 out of 122 infants, or 44%, progressed beyond stage 2, compared to 24 out of 103 infants, or 23%, in cohort B, after protocol implementation (between the years 2008–2012, P = 0.001. No other significant differences were found between cohorts A and B in respect of gestational age, birth weight, survival, sepsis, bronchopulmonary dysplasia, oxygen at discharge, or need for diuretics. According to the study results, “infants with stage 2 ROP in cohort B, with oxygen therapy protocol, had significantly decreased risk of ROP beyond stage 2 (odds ratio 0.37, 95% confidence interval 0.20–0.67; P = 0.0013), compared to cohort A, correcting for differences in birth weight and necrotizing enterocolitis.” In conclusion, the study suggests that an appropriately delivered oxygen therapy may significantly inhibit progression of stage 2 ROP, thereby improving outcomes of lifelong visual function among preterm infants.