Fatal respiratory distress syndrome after prolonged mechanical ventilation: its pathogenesis and prevention.

Abstract Prolonged pulmonary atelectasis was shown to produce a highly lethal respiratory distress syndrome. Atelectasis with secondary hypoxemia occurred in open-chest animals ventilated for long periods with intermittent positive pressure (IPPV). These animals frequently died of progressive pulmonary insufficiency a few days after the period of thoracotomy and mechanical ventilation. Atelectasis did not occur in closed-chest animals subjected to long periods of IPPV and these animals did not manifest pulmonary insufficiency after the period of ventilation. Continuous positive-pressure ventilation (CPPV) prevented atelectasis in open-chest animals during prolonged mechanical ventilation and thoracotomy, and animals so treated developed postoperative pulmonary insufficiency infrequently. It is concluded that atelectasis, which occurs during IPPV in open-chest animals, if prolonged, leads to progressive, bilateral massive pulmonary consolidation and death a few days after closure of the chest and termination of mechanical ventilation. This frequently fatal respiratory distress syndrome does not occur if atelectasis is prevented during mechanical ventilation.