Effect of age and preoperative airway obstruction on lung function after coronary artery bypass grafting

To determine whether age or obstructive lung disease affects pulmonary function changes caused by uncomplicated coronary artery bypass grafting, we measured pulmonary function before operation and then 3 or 4 days, 7 days, and 17 +/- 2.2 weeks after operation in elderly patients (age, 74.8 +/- 3.3 years) and patients with obstructive lung disease (ratio of forced expiratory volume in 1 second to forced vital capacity, 0.60 +/- 8.8) and compared the results with those of a "normal" group. In all three groups a severe restrictive defect developed on day 3 (vital capacity, 61% +/- 20% of the preoperative value). Vital capacity recovered to 76.4% +/- 18.5% of the preoperative value on day 7. Three months after coronary artery bypass grafting, lung function had recovered to preoperative baseline (p > 0.2). The percent change from baseline in vital capacity, forced expiratory volume in 1 second, total lung capacity, and diffusing capacity for carbon monoxide was the same in all three groups throughout the study. A severe, reversible restrictive pulmonary function change follows coronary artery bypass grafting. This change is not affected by age or preexisting moderately severe obstructive lung disease.