Open Abdominal Aortic Aneurysm Replacement in the Awake Patient

Abstract

We report a case of open replacement of an abdominal aortic aneurysm (AAA) under regional anesthesia alone. The potential benefits of the procedure are presented. Case ReportA 78-year-old man was found to have an asymptomatic 5.1-cm diameter AAA during investigation of hematuria for which no cause was ascertained. His medical history included type II diabetes mellitus, hypertension, vertebrobasilar insufficiency, cerebrovascular event, and emphysema. He was independent in daily living activities and had smoked daily for the past 60 years. Following initial assessment, he was enlisted in our ultrasound AAA surveillance program.Overall, 10 months from initial diagnosis, his aneurysm had increased in size to 5.6 cm diameter with a short dissection flap extending from the neck to the origin of the left common iliac artery (CIA) as defined by CT angiography. Two marked neck angulations were present, the most proximal measuring 58 degrees (►Fig. 1) and the second 71 degrees (►Fig. 2). Neck length was 30 mm and diameter was 19 mm. As such aneurysm neck angulations precluded endovascular stent grafting (endovascular aneurysm repair [EVAR]), he underwent preoperative anesthetic assessment of his suitability for open repair.The assessment included a full blood count, renal and coagulation profiles, and electrocardiogram, which were all within normal parameters. Echocardiography revealed normal left ventricular function with mild diastolic impairment. A chest radiograph showed gross emphysematous changes with an enormous bulla at the left lung base as confirmed by CT scan. Lung function tests revealed a forced expiratory volume over 1 second (FEV 1 ) of 1.0 L (36%) predicted and a forced vital capacity (FVC) of 2.56 L (70% predicted) (FEV 1 : FVC ¼ 53). FEF 25 to 75/FVC ¼ 16% predicted values. He described his exercise limit as being able to walk 100 yards on the flat and cardiopulmonary exercise testing demonstrated an anaerobic threshold of 12.7 mL/kg/min.In view of his poor respiratory function and in the face of particular concerns over intraoperative bullous rupture during positive pressure ventilation, it was felt that, because of an excessive perioperative risk, an open procedure would be performed under combined spinal and thoracic epidural anesthesia with bilateral transverses abdominis plane blocks, supplemented with intravenous sedation. No tracheal intubation or inhalation agents were used. A retroperitoneal approach Keywords ► abdominal aortic aneurysm ► epidural anesthesia ► regional anesthesia AbstractNonintubated aortic surgery using various techniques has been reported, but despite publication of favorable outcomes in select patient groups, awake aortic surgery remains unpopular. Our patient had an abdominal aortic aneurysm that was unsuitable for endovascular repair. Because of the significant respiratory disease, general anesthesia represented an unacceptably high risk. As a result, he underwent open AAA repair via a retroperitoneal approach with the aid of epidural anesthesia. Here, we highlight the ben...