Combined epidural and general anesthesia versus general anesthesia for abdominal aortic surgery

Abstract

The goal of this randomized study of high-risk surgical patients was to determine whether intraoperative thoracic epidural anesthesia in combination with light general anesthesia alters postoperative morbidity when compared to a standard technique of 'balanced' general anesthesia. A total of 173 patients scheduled for abdominal aortic reconstruction were admitted to the study; 86 were to receive 'balanced' general anesthesia (group 1) and 87 thoracic epidural anesthesia in combination with light general anesthesia (group 2). Preoperative evaluation included standard clinical tools, dipyridamole thallium gammatomography, and radionuclide angiography. In these patients, all of whom had peripheral artery disease, there were no significant differences in associated coronary artery disease, hypertension, and cardiovascular treatment. The distribution of left ventricular ejection fraction and the number of patients with thallium redistribution were not statistically different between the two groups. During the postoperative period, group 1 received analgesia of subcutaneous morphine (n = 35), epidural fentanyl (n = 30), or epidural bupivacaine (n = 21). In group 2, 6 patients with a nonfunctioning epidural catheter due to technical failure received a balanced general anesthesia and were eliminated from the study. During the postoperative period, group 2 received analgesia of subcutaneous morphine (n = 26), epidural fentanyl (n = 25), or epidural bupivacaine (n = 30). Cardiovascular morbidity did not differ between the two groups: 22 patients in group 1 and 19 patients in group 2 had a major postoperative cardiac event. Myocardial infarction was diagnosed in 5 patients in each group, congestive heart failure in 7 patients in group 1 and 5 patients in group 2, and prolonged myocardial ischemia in 16 patients in each group. Respiratory morbidity was extremely high (61% in group 1 and 55% in group 2) and not significantly different between the two groups. The major part of this respiratory morbidity consisted of minor atelectasis. Acute respiratory failure occurred in 8 patients in group 1 and in 4 patients in group 2. Four patients in group 1 and 3 patients in group 2 died. We conclude that thoracic epidural anesthesia in combination with light general anesthesia is not preferable to general anesthesia in high-risk surgical patients. This study does not exclude the possibility that postoperative epidural analgesia may favorably influence post-operative outcome.