[Predictor indices of early extubation in mechanical ventilation in patients treated with heart surgery]

Following open heart surgery, most patients are ventilated for 12 to 24 hours to obtain a period of hemodynamic stability and to reduce the work of breathing. Some authors have proposed criteria to guide early extubation and have proposed physiologic parameters to predict which patients will be able to breathe spontaneously.

To study the capacity to predict successful early extubation of ventilatory and gas exchange parameters.

Two hundred thirty patients admitted to an intensive care unit after coronary or valvular surgery were studied. Measurements were made through a T piece 30 minutes after discontinuing mechanical ventilation.

Six patients died in the postoperative period. Two hundred ten patients tolerated early extubation (14 +/- 5 h of mechanical ventilation) and 20 required prolonged mechanical ventilation (74 +/- 107 h). The latter had longer surgical procedures (291 +/- 65 and 240 +/- 67 min respectively) and extracorporeal circulation times (138 +/- 42 and 104 +/- 43 min respectively), required more vasoactive drugs, had more episodes of confusion and had a higher surgical risk. Tidal volume, respiratory frequency, maximal inspiratory pressure and blood gases at the moment of extubation were similar in both groups.

Pulmonary function parameters and blood gases measured during a T piece trial are not good predictors of early extubation in cardiac surgery.