A Study to Predict Post Cross Clamp Venous Oxygen Saturation by Tricuspid Annular Plane Systolic Excursion and Transpulmonary Gradient in Chronic Obstructive Pulmonary Disease Patients Undergoing on Pump Coronary Artery Bypass Grafting

Abstract

Context : Patients with COPD are at increased risk of coronary artery disease (CAD) and, conversely, CAD is associated with the diagnosis and severity of COPD . Due to secondary pulmonary hypertension, right ventricular hypertrophy and ischaemia are known to occur in COPD. The purpose of our study is to compare two preoperative echocardiographic parameters; TAPSE and Transpulmonary Pressure Gradient (TPG), to quantify RV dysfunction to predict post cardiopulmonary bypass decreased venous oxygen saturation in COPD patients undergoing CABG. Aims : To find out the correlation of TAPSE and TPG with the changes of venous oxygen saturation after release of cross clamp. Settings and design: After obtaining institutional ethics committee clearance and informed consent from each patient 60 COPD patients undergoing on-pump CABG for CAD, were included in this study over a period of one and half year. Material and methods:After institution of general anaesthesia TAPSE and TPG were measured before any incision. SvO2 was measured before going on bypass and one hour after release of cross clamp. Statistical analysis used: Data were analyzed using standard statistical software Epi Info (TM) 7.2.2.2. Result and conclusion: TPG has better predictive accuracy in comparison to TAPSE (91.67% vs 61.67%) to predict low SvO2 after coming out of bypass, following CABG.