Thoracic epidural analgesia in obese patients with body mass index of more than 30 kg/m 2 for off pump coronary artery bypass surgery

Abstract

Perioperative Thoracic epidural analgesia (TEA) is an important part of a multimodal approach to improve analgesia and patient outcome after cardiac and thoracic surgery. This is particularly important for obese patients undergoing off pump coronary artery bypass surgery (OPCAB). We conducted a randomized clinical trial at tertiary care cardiac institute to compare the effect of TEA and conventional opioid based analgesia on perioperative lung functions and pain scores in obese patients undergoing OPCAB. Sixty obese patients with body mass index >30 kg/m2 for elective OPCAB were randomized into two groups (n=30 each). Patients in both the groups received general anesthesia but in group 1, TEA was also administered. We performed spirometry as preoperative assessment and at six hours, 24 hours, second, third, fourth and fifth day after extubation, along with arterial blood gases analysis. Visual analogue scale at rest and on coughing was recorded to assess the degree of analgesia. The other parameters observed were: time to endotracheal extubation, oxygen withdrawal time and intensive care unit length of stay. On statistical analysis there was a significant difference in Vital Capacity at six hours, 24 hours, second and third day postextubation. Forced vital capacity and forced expiratory volume in one second followed the same pattern for first four postoperative days and peak expiratory flow rate remained statistically high till second postoperative day. ABG values and PaO2/FiO2 ratio were statistically higher in the study group up to five days. Visual analogue scale at rest and on coughing was significantly lower till fourth and third postoperative day respectively. Tracheal extubation time, oxygen withdrawal time and ICU stay were significantly less in group 1. The use of TEA resulted in better analgesia, early tracheal extubation and shorter ICU stay and should be considered for obese patients undergoing OPCAB.