The role of respirators in the etiology and pathogenesis of bronchopulmonary dysplasia

Abstract

I N P R O P O S I N G T H E U S E o f the term bronchopulmonary dysplasia, Northway et al' described the occurrence of pulmonary disease following respirator therapy in hyaline membrane disease and proposed the appearance of a new chronic pulmonary syndrome associated with the use of intermittent positive pressure, respirators and high oxygen concentrations for a period exceeding 156 hours. A review of their material also indicates that the patients described were all managed with endotracheal tubes and that the choice of the 156-hour period was dictated simply by what the material itself contained rather than by any predirected time pattern. It is questionable, however, whether what was being described at that point was really a new disease or simply the recognition that respirators, by being able to prolong the course of hyaline membrane disease, were now allowing the appearance of the normal progression of severe cases of the disease, in that all of our previous experience had indicated either death or complete resolution of the changes without any permanent sequelae. There had been previous suggestions that sequelae from the natural course of the disease did occur, 2a and that complete pulmonary recovery could not always be expected, although in both of these instances the management of the infants had been complicated by both oxygen therapy and the use of respirators, thus making it difficult to ascribe these changes to the natural course of severe disease itself. That even mild cases could subsequently lead to both anatomic and functional sequelae in later life was subsequently demonstrated by the report of the occurrence of a much higher incidence of bronchiolitis at an early age in survivors of respiratory distress syndromer an incidence which seems to be independent of either the severity of the initial disease or of the existence of permanent radiographic changes, thus suggesting that functional sequelae and visible anatomic changes may or may not go together in all instances. The suggestion that this is specifically an occurrence confined to the newborn period may be open to question, since changes of similar nature have been described in adults managed with oxygen and positive pressure respirators?