Unplanned extubation. Predictors of successful termination of mechanical ventilatory support

Unplanned extubation (self-extubation or accidental extubation) occurs commonly in mechanically ventilated patients, and many patients do not receive mechanical ventilation indefinitely. Unfortunately, weaning parameters are often unavailable in the setting of unplanned extubation, and it would be useful to define pre-extubation respiratory and ventilatory parameters that predict which patients require reintubation.

The medical records of all patients who experienced unplanned extubation for the 2-year period of July 1989 to July 1991 were reviewed. Pre-extubation values of respiratory rate, tidal volume (VT), fraction of inspired oxygen (FIo2), PEEP, ventilatory mode, and ventilator-delivered minute volume (VVE, ventilator rate multiplied by set VT) were recorded. In addition, the following data were obtained: age, gender, respiratory failure diagnosis, duration of intubation, amount, and type of sedative agents in the 24 h before extubation. Comparisons of these values among patients who ultimately required reintubation and those who were not reintubated were made using the Mann-Whitney U two-sample test.

During this period, there were 23 unplanned extubations involving 22 patients. Reintubation was required for 18 episodes of unplanned extubation, but was not required for 5 episodes. There were no significant differences between the two groups for any of the parameters except VVE and FIo2. The mean pre-extubation FIo2 of the reintubated group (0.49) was significantly higher than that of the patients who were not reintubated (0.35) (p = 0.021); all of the patients who remained extubated were receiving an FIo2 < or = 0.40. The VVE was also higher in the reintubated group (9.73 L/min) than in the patients who were not reintubated (1.40 L/min); all patients who remained extubated were receiving < or = 7.0 L/min of ventilator-delivered minute ventilation.

Reintubation after unplanned extubation should not be considered mandatory. Patients who require reintubation have significantly higher preextubation FIo2 and ventilatory requirements than patients who remain extubated.