Off-pump coronary artery bypass surgery: evaluation of extubation time and predictors of failed early extubation

Abstract

Anesthesia during and after off-pump surgery is critical for the outcome of the procedure. Intubation time has been shown to correlate with ICU time and length of stay. This study is to evaluate the extubation time and predictors of prolonged extubation in this institution. One hundred and sixty consecutive patients during Jan 2001-June 2002, excluding pre-operative tracheostomy (n = 1) were retrospectively reviewed. Anesthetic agents include fentanyl, rocuronium Bromide, midazolam and sevoflurane. Phenylephrine and nitroglycerine were used to maintain adequate arterial pressures. Post-operative pain control was mainly with intravenous fentanyl and oral pain medications. The extubation time was divided into 4 groups; 0-2 h, n = 76, mean = 1.11 +/- 0.5 h; 2-4 h, n = 30, mean = 2.91 +/- 0.5 h; 4-24 h, n = 39, mean = 11.44 +/- 7.3 h; > 24 h, n = 5, mean = 33.3 +/- 21 h. The data were collected and analyzed following the guidelines of National STS cardiac surgery database. All pre-operative risk factors included: Age (> 70 yrs vs < or = 70 yrs), gender (male vs female), diabetes (yes vs no), hypertension (yes vs no), morbid obesity (yes vs no), renal insufficiency (yes vs no), chronic obstructive lung disease (yes vs no), history of cerebrovascular accident (yes vs no), smoking (yes vs no), dyslipidemia (yes vs no), history of myocardial infarction (MI) (yes vs no), history of congestive heart failure (CHF) (yes vs no), unstable angina (yes vs no), left ventricular ejection fraction (LVEF) (> 40% vs < or = 40%), left main (LM) lesion (LM > 50% vs LM < or = 50%), intra-aortic balloon pump (IABP) used (yes vs no) and time between operating and closing (> 4.30 h vs < or = 4.30 h) were used to predict failed early extubation (2 h). More than 50 per cent of the patients were extubated in less than 2 h (1.11 +/- 0.5 h) and only 5 patients were extubated after 24 h. Univariate analysis revealed old age, diabetes, MI, CHF, LVEF < or = 0.4 and the use of IABP are the predictors (p < 0.05) of failed early extubation. Multivariate analysis of these variables revealed old age with adjusted odds ratio of 4.6 (95% CI = 1.5-13.7) p < 0.01, diabetes with adjusted odds ratio of 3.2 (95% CI = 1.3-7.5) p < 0.01 and IABP used with adjusted odds ratio of 4.3 (95% CI = 1.3-14.6) p = 0.02 are the predictors of fail early extubation. The findings suggested early extubation is possible in OPCAB surgery and attention should be made when operate in patients who have old age, diabetes, and IABP used.