Comparison between thoracic epidural and systemic opioid analgesia on lung mechanics in obese patients in major gynecological procedures

Abstract

Background The study was conducted to compare the effects of thoracic epidural analgesia versus systemic opioid analgesia on lung mechanics in obese patients undergoing major gynecological procedures (abdominal hysterectomy, ovarian cyst, ovarian mass, and abdominal explorations). We evaluated their analgesic efficacy over the first 12 postoperative hours after gynecological surgeries, in a randomized, single-blind, clinical trial in 60 patients divided into two equal groups, with 30 patients in each group. Patients and methods Sixty patients were randomized into two equal groups, with 30 patients in each group: group I received general anesthesia in combination with intravenous opioids, and group II received general anesthesia in combination with thoracic epidural anesthesia. General anesthesia was induced with fentanyl 1–2 μg/kg and propofol 1–3 mg/kg followed by rocuronium 0.6 mg/kg. Each patient was assessed for pulmonary function tests, pethidine consumption, visual analog pain scale at rest and on movement, vital signs and the presence of complications (nausea, vomiting, sedation, and pruritus) postoperatively by a blinded investigator in the postanesthesia care unit and at 1, 3, 6, and 12 h postoperatively. Results Group II patients showed significantly increased postoperative pulmonary function test values compared with group I patients at 1, 3, and 6 h; the postoperative analgesia is more effective with group II than with group I (epidural>systemic opioid), and the postoperative consumption of pethidine in the epidural group is lower than in the opioid group. As regards complications during the study in all groups, complications such as nausea, vomiting, pruritus, and sedation were recorded, which were more in the systemic opioid group than in the epidural group. Conclusion Particularly for obese patients, epidural anesthesia and postoperative epidural analgesia improve the postoperative respiratory functions, compared with general anesthesia and systemic analgesia, and reduce postoperative pain in obese patients undergoing major gynecological procedures.