From 1972 through 1975, a total of 6,196 patients were admitted to San Francisco General Hospital Trauma Service, of whom 908 required admission to an intensive care unit and 390 required mechanical ventilation. Duration of mechanical ventilation was one week or less for 76%, two weeks or less for 90%, and four weeks or less for 97%. Survival in patients ventilated seven days or less was 64%, in patients ventilated 8 to 14 days it was 55%, and in patients ventilated 15 to 30 days it was 55%. The mortality for ventilated patients aged 20 to 49 years was 23% while for ventilated patients older than age 60 it was 53%. The average age of ventilated patients was 43. Use of controlled-pressure soft-cuff endotracheal tubes has eliminated tracheal-esophageal fistula and tracheal stenosis as causes of morbidity and mortality. Appropriate ventilator alarms have minimized fatalities due to mechanical equipment failure. Complications related to positive pressure ventilation, such as pneumothorax and subcutaneous emphysema, still occur in 12% to 18% of patients. In our patients who survived the acute respiratory distress syndrome, recovery of lung function was universal, and permanent disability was less than 1%.