Predictors and outcomes associated with early extubation in older adults undergoing coronary artery bypass surgery

BACKGROUND: Older age has been associated with prolonged mechanical ventilation after coronary artery bypass surgery. Prolonged mechanical ventilation contributes to increased morbidity and mortality and to use of limited financial resources among older adults. OBJECTIVES: To examine selected physiological and pathophysiological variables ofpresurgicalpatients to predict duration of mechanical ventilation in older adults after coronary artery bypass surgery. METHODS: Nonrandomized study of a clinical database of 919 patients (> or =65 years old) who had coronary artery bypass surgery between October 1996 and December 1997. RESULTS: Median elapsed time after coronary artery bypass surgery until extubation was used to sort patients into 2 groups: group 1, 6 hours or fewer (n = 464); and group 2, more than 6 hours (n = 455). With stepwise logistic regression, the physiological model included age (odds ratio, 1.05; P<.001) and female sex (odds ratio, 1.48; P = .005) with weak discrimination by group (concordance statistic = 0.5880). The pathophysiological model, which included renal insufficiency (odds ratio, 3.28; P = .01), previous peripheral vascular surgery (odds ratio, 2.87; P = .03), nonelective preoperative clinical status (odds ratio, 2.8; P = .006), congestive heartfailure (odds ratio, 2.6; P<.001), and reoperation (odds ratio, 2.34; P = .007), showed moderate discrimination bygroup (concordance statistic =0.6755). CONCLUSION: Many older adults were easily extubated and had good outcomes. The variables comorbid conditions and severity of illness provided better discrimination between extubation groups than a physiological model provided. Both predictive models allowed limited discrimination between groups.