CHANGING RECOMMENDATIONS AND PRACTICE IN THE USE OF OXYGEN
On completion of the Cooperative Study of RLF, three controlled clinical trials conducted in 20 premature nurseries had unequivocally related oxygen therapy to RLF. This resulted in new recommendations to limit the use of oxygen. Although the studies of both Lanman and coworkers (1954) and Kinsey and Hemphill (1955) had not demonstrated any increase in mortality with restricted use of oxygen, many physicians were skeptical, partly because of their early training and the previous long-standing clinical experience and partly because of their fear of producing hypoxic brain damage. Nevertheless, notable changes in practice took place, and the use of oxygen was severely curtailed. The first increase in perinatal mortality in the United States occurred in 1955. At first this increase could not be ascribed to the restricted use of oxygen. However, recent analysis of subsequent mortality trends, both in the United States and Great Britain, over the next ten years of limited oxygen use (Cross 1973) has suggested that the increased mortality was indeed associated with the decreased use of oxygen. RECOMMENDATIONS Prior to 1955, the recognized textbooks of pediatrics available to pediatricians advised that oxygen be used liberally. The 12th edition of Pediatrics (Holt and McIntosh, 1953) recommended: ". . . as a rule the oxygen content of the incubator need not exceed 60%, although higher concentrations appear to do no harm and may serve to tide the patient over a spell of anoxia." In 1954 the Textbook of Pediatrics (Nelson) stated: "For the small premature infant just admitted to the nursery, observation in an atmosphere of 40 to 60 percent oxygen for a few hours or days, followed . . . ."