Background and Objectives. Elderly patients undergoing surgery present special risks because of coexisting disease. The choice of regional techniques offers several advantages: the blocking of nociceptive transmission that diminishes the stress response, postoperative analgesia, the risk of deep venous thrombosis, and the need for airway manipulation. Subarachnoid anesthesia offers a clear end point for needle placement, rapid onset, and low dose of local anesthetic. The purpose of the present study is to compare the efficacy and safety of the continuous subarachnoid anesthesia (CSA) and the single dose subarachnoid anesthesia (SA) in patients presenting for peripheral arterial vascular surgery of the lower limbs.

Methods. A prospective study involving 112 consecutive patients was performed. Seventy patients undergoing surgery expected to last over 3 hours received CSA and the remainder received a single dose. The local anesthetic used was plain bupivacaine 0.5%.

Results. Both groups were identical in terms of coexisting disease. The total dose in the CSA group was 7.7 ± 0.8 mg versus that of the SA group that was 16.5 ± 3.7 mg (P < .001). The mean level of sensory block was similar, corresponding to the spinal segments T9 (CSA) and T10 (SA). The degree of motor block was higher in the SA group (P < .001). We did not find any differences in technical difficulties, incidence of postdural puncture headache, or hemodynamic changes. No prolonged neurologic problems were found in either group. Postoperative mortality was also comparable.

Conclusions. Both CSA and SA are appropriate techniques for elderly patients undergoing peripheral vascular surgery of the lower limb; CSA has the advantage of providing a longer duration of anesthesia.