Sequential Changes In Pulmonary Functions After Coronary Artery Bypass Graft Surgery.

ABSTRACT

Impaired pulmonary functions are common in cardiac patients undergoing coronary artery bypass graft (CABG) surgery. The objective of this study was to study sequential changes in pulmonary functions tests up to a period of 4 months after surgery. 50 patients undergoing CABG surgery were included in the study & their pulmonary functions were tested prior to surgery and repeated 7 days, 1 month and 4 months after surgery.It has been found that forced vital capacity (FVC) dropped from 85% of predicted preoperative value to 56% (P = 0.0000) on 7th postoperative day, recovered to 71.6% (P = 0.0000) 1 months after and to 84.2% (P = 0.4008) 4 months after the surgery. Forced expiratory volume in 1st second (FEV1) decreased from 88.38% to 59.06% (P = 0.0000) on the 7th postoperative day and recovered to 75.42% (P = 0.000) 1 month after the surgery and to 85.78% (P = 0.0308) 4 months after the surgery. Ratio of FEV1/FVC improved marginally from 79% preoperative value to 81% on 7th postoperative day and 1 month after and again reached to 78%, 4 months after the surgery suggestive of a restrictive ventilatory defect. We conclude that CABG produces long term changes in pulmonary functions hence pre and postoperative evaluation of pulmonary function should be done as a routine even if the patient is asymptomatic.