Serial peak expiratory flow rates in patients undergoing upper abdominal surgeries under general anaesthesia and thoracic epidural analgesia

Introduction: Anaesthesia and upper abdominal surgeries alter lung compliance and functional residual capacity resulting from atelectasis. Upper abdominal surgeries also cause a decrease in peak expiratory flow rates, cough reflex due to pain limited inspiration. Aim: This study aimed to study the effect of thoracic epidural analgesia (TEA) on the peak expiratory flow rates in patients undergoing upper abdominal surgeries. Materials and Methods: A total of 44 patients posted for elective surgery were enrolled. Group 1 patients received GA + 0.125% bupivacaine infusion TEA and Group 2 received GA + Inj. Diclofenac sodium 50 mg slow i.v. TID for Postoperative analgesia. Haemodynamics, VAS pain score, PEFR measurements were done at 60 minutes, 24 hours, 48 hours and 4 days after surgery in both groups. ABG analysis was taken pre operatively and 24 hours after surgery. Results: The SBP and DBP values obtained at 60 minutes (p<0.016) 24 and 48 hours (p<0.001) and day 4 (p<0.02) postoperative showed highly significant difference between the two groups which indicate better haemodynamic parameters in patients receiving epidural analgesia. Postoperatively the difference in PEFR values at 60 minutes, 24 hour, 48 hour and day 4 were very highly significant. (p<0.001). Group1 had a 10.739% deficit on day 4 from its pre operative baseline value while group 2 showed a 34.825 % deficit which was very highly significant (p<0.001). The difference in VAS scores recorded at 60 minutes, 24 hours, 48 hours and day 4 post op were very highly statistically significant (p < 0.001).The ABG taken at 24 hours shows statistically significant difference with patients in group 2 showing decreased values in pCO₂ and pO₂ reflecting poorer ventilation and oxygenation. Conclusion: Thoracic epidural analgesia provides superior analgesia, better cough reflex as seen by better PEFR values, were haemodynamically more stable and their ABG values were better than the NSAID group.