Background: Different types of analgesia have been proposed for the prevention of postoperative respiratory complications. The aim of this prospective, double-blind randomized study was to compare the impact of epidural bupivacaine and opioids versus parenteral opioids on respiratory complications in patients who had undergone major abdominal surgery.
Methods: One hundred fifty-three patients undergoing abdominal surgery for cancer were randomly allocated to receive either general anesthesia with intravenous fentanyl and postoperative analgesia with subcutaneous morphine (SC group) or general anesthesia combined with epidural bupivacaine and epidural bupivacaine plus morphine for postoperative pain relief (EP group). Analgesia was tested on a visual analog pain scale. Pulmonary complications were evaluated according to clinical complications, chest radiographs, arterial blood gas analysis, and pulmonary function tests. The evaluation was carried out on the day before the operation and on the first 5 postoperative days. Particular attention also was paid to the episodes of arterial hypotension and hemoglobin oxygen desaturation during the 1st postoperative night.
Results: Pain relief was significantly better in the EP group than in the SC group (P < 0.05) especially during recovery and on the 1st and 2nd postoperative days. In the EP group, vital capacity decreased less on the 1st postoperative day (P < 0.05) and arterial oxygen tension was greater in the recovery room (P < 0.05). However, no statistically significant difference was observed between the SC and EP groups in the incidence of clinical pulmonary complications (31% and 27%, respectively) and radiographic chest abnormalities (52% and 46%, respectively). The EP group recovered intestinal function earlier (P < 0.05), but significantly more patients in this group had episodes of systolic hypotension (21% vs. 8%; P < 0.05) during the 1st postoperative night. The length of the hospital stay was similar in both groups of treatment.
Conclusions: Epidural analgesia with a combination of local anesthetic and opioid improves patient comfort. However, this type of analgesia does not decrease the incidence of postoperative pulmonary complications, does not reduce the length of the hospital stay, and carries the risk of complications from episodic systemic hypotension.