Several years after the introduction of the mechanical respirator Smith1 called attention to the fact that one third of the patients who had been in respirators and were discharged to various orthopedic hospitals and convalescent homes died with infections of the respiratory tract, reported in the hospital records as bronchopneumonia. A review of the records of 2 such patients and postmortem studies on a third led him to believe, however, that the pulmonary infections develop secondarily to atelectasis produced by obstruction of the bronchi by unexpelled exudate. Coryllos and Birnbaum2 had previously emphasized the importance of the role of atelectasis in the development of pneumonia, and there has since developed a considerable interest with regard to the mechanical effects of obstructing bronchial exudate in infections of the respiratory tract in general.
In paralysis of the respiratory muscles due to poliomyelitis a number of factors predispose to the development