Reduced severity of oxygen-induced retinopathy in kittens recovered in 28% oxygen

Chronic hypoxemia adversely affects the retinopathy observed in kittens after a hyperoxic exposure (80% oxygen) in the 1st wk of life. To test the converse hypothesis, 55 kittens were randomly assigned to recover in room air (21%) or 28% inspired oxygen after a 65-h hyperoxic exposure. At 4 wk of age, the retinopathy was found to be less severe in the 28% recovered kittens, severity score 3.0 +/- 3.3 (mean +/- SD), than in the room air recovered animals, severity score 5.7 +/- 3.3, p less than 0.01. This finding suggests that the clinical practice of restricted oxygenation in premature infants warrants reevaluation.