Measurement of ventilatory reserve as an indicator for early extubation after cardiac operation.

The decision to perform tracheal extubation in 44 patients who underwent cardiac operation was based on an assessment of mental alertness, recovery of muscle strength, hemodynamic stability, and adequacy of pulmonary gas exchange. No patients required reintubation. Concomitant measurements of vital capacity (VC) and maximal inspiratory pressure (PImax) were made before a trial of spontaneous ventilation was commenced, after 45 minutes of spontaneous ventilation, and after tracheal extubation. By generally accepted criteria, these measurements suggested the need for continuing mechanical ventilation in 14 patients at the time mechanical ventilatory support was removed and in eight patients at the time of tracheal extubation. In this study, consideration of measurements of VC and PImax would have led to longer trachael intubation, especially in those patients who were extubated within 10 hours of the completion of anesthesia.