The effect of extubation within the first postoperative hour was evaluated in 13 patients (mean +/- SD age 59 +/- 6 years) undergoing elective coronary artery bypass surgery without active systemic hypothermia. The mean cardiopulmonary bypass time was 50 +/- 14 minutes. Postoperative improvements in cardiac index and oxygen uptake (from 2.0 +/- 0.4 l/min/m2 and 144 +/- 26 ml/min postinduction to 2.88 +/- 0.76 l/min/m2 and 229 +/- 104 ml/min, p less than 0.01) were maintained following extubation. Lower postoperative systemic and pulmonary vascular resistances (p less than 0.01) did not change to a significant extent following extubation. Despite a two-fold rise in the intrapulmonary shunt (Qs/Qt) following surgery (18.5 +/- 9.7% vs 9.6 +/- 3.2% before surgery) the immediate post-extubation value was similar (18.8 +/- 8.2%) and all patients were discharged from the cardiac recovery area within 16 hours without complication. Extubation within the first postoperative hour is a safe procedure following elective coronary artery surgery with short bypass times where sustained hypothermia less than 32 degrees C is avoided.