Background: 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 pre
dict which patients will be able to breathe spontaneously. Aim: To stu
dy the capacity to predict successful early extubation of ventilatory
and gas exchange parameters. Patients and method: Two hundred thirty p
atients admitted to any intensive care unit after coronary or vascular
surgery were studied. Measurements were made through a T piece 30 min
utes after discontinuing mechanical ventilation. Results: Six patients
died in the postoperative period. Two hundred ten patients tolerated
early extubation (14 +/- 5 h of mechanical ventilation) and 20 require
d prolonged mechanical ventilation (74 +/- 107 h). The latter had long
er surgical procedures (291 +/- 65 and 240 +/- 67 min respectively) an
d extracorporeal circulation times (138 +/- 42 and 104 +/- 43 min resp
ectively), required more vasoactive drugs, had more episodes of confus
ion and had a higher surgical risk. Tidal volume, respiratory frequenc
y, maximal inspiratory pressure and blood gases at the moment of extub
ation were similar in both groups. Conclusions: Pulmonary function par
ameters and blood gases measured during a T piece trial are not good p
redictors of early extubation in cardiac surgery.