Permissive hypercapnia ventilation in patients with severe pulmonary blast injury

Objectives: To describe our experience with the use of limited peak inspiratory pressure (PIP), volume-controlled ventilation, and permissive hypercapnia in patients with severe pulmonary blast injury. Methods: Patients with pulmonary blast injury were ventilated using volume-controlled, synchronized intermittent mandatory ventilation. Whenever PIP exceeded 40 cm H₂O, the tidal volume was decreased to maintain PIP at less than 40 cm H₂O. Whenever the arterial pH fell below 7.2, the ventilator rate was increased in increments of 2 breaths per minute until the arterial pH rose to 7.25. Results: Between 1994 and 1996, 17 patients with severe pulmonary blast injury (10 from enclosed space explosions and seven from open space ones), requiring mechanical ventilatory support were admitted to our intensive care unit. Four patients developed increasing Paco₂ levels (to 93 ± 12 mm Hg) associated with the reduction in arterial pH that was corrected by increasing the ventilator rate. There was evidence of ventilator-induced pulmonary barotrauma. Of the 17 patients, 15 patients (88%) survived. Conclusions: Limited PIP in a volume-controlled ventilation is a useful and safe mode of mechanical ventilation in patients with pulmonary blast injury.