Con: epidural anesthesia is not a valuable adjunct to general anesthesia for abdominal vascular surgery.

p ATIENTS WITH peripheral vascular disease have a high incidence of concomitant coronary artery disease? and myocardial infarction is the leading cause of death following aortic surgery. 2 For these reasons, stable hemodynamics are a prerequisite regardless of the anesthetic technique. Anesthetic morbidity in these patients usually occurs immediately following induction and intubation, following aortic cross-clamping, and upon aortic unclamping. Epidural analgesia alone does not provide adequate surgical conditions for abdominal vascular surgery, and combining it with general anesthesia compounds the risks. A balanced general anesthesia technique provides adequate surgical conditions without myocardial depression. Afterload reduction can be accomplished with the administration of a vasodilator, such as sodium nitroprusside, the effect of which disappears upon termination of the infusion. Epidural anesthesia can produce hypotension, which is poorly tolerated in patients with coronary artery disease. To compensate for the hypotension, volume infusion before inserting the catheter and establishing the block is recommended. Elimination of the efferent sympathetic drive produces vasodilatation in the region of the block, including two to three segments above the level of the somatic block? Compensatory vasoconstriction occurs above the level of the sympathetic block in an attempt to counterbalance the reduction in the peripheral resistance resulting from the block. This reflex sympathetic stimulation involves the cardiac sympathetic nerves producing coronary vasoconstriction and myocardial ischemia. 3 Krantz et al 3 reported a case in which the patient developed Prinzmetal's angina during epidural anethesia. Lunn et al 4 compared the cardiovascular responses to clamping of the aorta during epidural and general anesthesia. Their data showed that patients who had epidural anesthesia as an adjunct to general anesthesia experienced severe decreases in blood pressure and pulmonary capillary wedge pressure (PCWP) upon removal of the aortic clamp, whereas patients who received general anesthesia alone did not. They explained the differences between the two groups on the basis of an increase in the capacitance vessel volume secondary to the sympathetic blockade associated with epidural anesthesia. 4 Stanton-Hicks 5 reported that there was a linear relationship between the level of the epidural block and the degree of hypotension. He added that a person could normally compensate for this sympathetic block up to the T 5 level by producing vasoconstriction in the upper part of the body. However, if hypovolemia is present, the compensatory mechanism will be impaired. Hypotension, in rare instances, can result in neurologic deficits? Bunt et al 7 studied 25 patients who underwent abdominal aortic reconstruction; 10 of these patients had general anesthesia supplemented with epidural block. Their study indicated potential difficulties in the intraoperative management of patients who underwent aortic resection under epidural anesthesia supplemented with general anesthesia. They identified two problems: (1) a tendency toward excessive perioperative volume administration, and (2) left ventricular dysfunction that was refractory to volume or inotropic manipulation. They reported that the epidural group received an average of 3,080 mL of excess volume.7 Another problem with the use of epidural anesthesia in abdominal vascular surgery is the risk of the development of an epidural hematoma. It has been reported that the incidence of epidural hemorrhage is increased in patients receiving anticoagulants and those with blood dyscrasias, thrombocytopenia, leukemia, hemophilia, and alcoholism, as well as those undergoing heparin therapy, s'12 Since heparin is used in most patients undergoing abdominal vascular reconstruction, these patients are at a greater risk of developing epidural hematomas than are