Effects of marginal hypoxemia on recovery from oxygen-induced retinopathy in the kitten model

Prolonged oxygen administration in premature infants is the most predictive variable for severe retinopathy of prematurity, after degree of prematurity itself. It was noted that infants receiving prolonged oxygen supplementation are probably hypoxemic relative to their healthy counterparts. Therefore, hypoxemia during recovery from a hyperoxic-induced retinal vascular injury was tested in the kitten model of oxygen-induced retinopathy. Twelve litters were exposed to 80% inspired O2 for 65 hours on day 3, and recovered in room air, 13% or 17% oxygen. The retinas were scored at 4 weeks, and 13% oxygen recovery (PO2 = 39 +/- 18 torr) was found to worsen significantly the retinopathy compared with that in room air-recovered littermates (P less than .01). Hemorrhages occurred more frequently in the retinas from the hypoxemic-recovered kittens. Clinical trials of this hypothesis are indicated in humans.