Effect of Coronary Artery Bypass Grafting Surgery on Pulmonary Function Tests and Arterial Blood Gases.

Background and objective: Pulmonary dysfunction after open heart surgery is an important cause of post-operative morbidity. To evaluate effect of coronary artery bypass grafting (CABG) surgery on pulmonary functions and arterial blood gases (ABGs).

Methods: A prospective study was conducted at a pulmonary unit of a tertiary care public hospital. Of the 50, patients enrolled, 42 patients completed the study. Spirometry was performed one week pre-operatively and within four to five weeks post-operatively. Arterial blood gas samples were also collected just before spirometry. The pre- and post-operative data were compared.

Results: There was significant reduction in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) by 13.8% and 13.1%, respectively within five weeks of surgery. After surgery mean maximum voluntary ventilation (MVV) showed a significant decrease of 7.6%. Post-operatively, the mean pH decreased significantly by 0.1% and the mean partial pressure of oxygen (PaO2) and oxygen saturation SpO2-showed significant decrease of 10.1% and 2.4%, respectively.

Conclusion: Coronary artery bypass grafting has an adverse impact on lung functions and ABGs.