Continuous epidural anesthesia for aortic surgery: thoughts on peer review and safety

Continuous epidural anesthesia (CEPA) has been recommended on the basis of limited reported experience as being safe to use during elective peripheral revascularization. This study surveyed peer acceptance and safety by means of a questionnaire that was mailed to the 190 members of the Southern Association for Vascular Surgery (52% rate of response). Of the respondents, 42% used CEPA and 54% considered it safe; 895 cases were compiled without complication. Twenty-five consecutive patients undergoing abdominal aortic reconstruction were then studied under a prospective protocol, which measured left ventricular function perioperatively. Preanesthetic, nitroglycerin-induced volume loading averaged 3570 ml in 15 general anesthesia (GA) cases and 3463 ml in 10 CEPA cases. Intraoperative volumes averaged 4341 ml GA and 6350 ml CEPA; after correction for blood loss per administration, patients in whom CEPA was used received an average 3080 ml excess volume. Eighteen-hour postoperative volumes averaged 1750 ml GA and 3156 ml CEPA. In the GA cohort, cardiac index fell from 3.57 to 2.80 L/min-m2 and rebounded to 3.07 L/min-m2 after unclamping. Left ventricular stroke work index fell from 56 to 46 gm-m/m2 (p less than 0.05), remained greater than 45 throughout clamping, and rebounded to 51 after unclamping. In the CEPA cohort, cardiac index fell from 3.50 to 2.85 L/min-m2 after supplemental GA administration, fell to a low of 2.30 L/min-m2 and remained at that range throughout the study; left ventricular stroke work index fell from 50 to 35 gm-m/m2 and remained depressed throughout. All intraoperative values were significantly (p less than 0.001 to p less than 0.05) depressed from baseline values, and from before unclamping and onward they were significantly (p less than 0.01) depressed as compared with those of the GA cohort. The use of CEPA has moderate peer group acceptance and apparently few major technique-related complications in elective revascularization cases. In aortic surgical procedures, and when combined with GA, the use of CEPA results in greater total perioperative fluid volume administration and has the potential for subtle left ventricular dysfunction.