THE EFFECT OF EPIDURAL-ANESTHESIA ON PERIPHERAL RESISTANCE AND GRAFT FLOW FOLLOWING FEMORODISTAL RECONSTRUCTION

Objective: To determine the extent to which epidural anaesthesia influences peripheral resistance and graft blood flow following femorocrural reconstruction. Design: Prospective, controlled study measuring blood flow, arterial pressure and peripheral resistance in femorocrural bypass grafts for 20 min following onset of epidural anaesthesia with 15ml of 0.25% bupivacaine. Patients: Twenty patients undergoing femorocrural reconstruction for critical lower-limb ischaemia with in situ long saphenous vein, under general anaesthesia. Ten patients had epidural cannulae inserted preoperatively and injected with bupivacaine after completion of the graft. Results: Peripheral resistance fell in all 10 patients receiving epidural anaesthesia from a mean (range) of 1.07 PRU (0.32-2.2) to 0.49 PRU (0.19-0.72), compared to control values of 0.95 PRU (0.39-2.0) to 0.91 PRU (0.41-1.51; P < 0.01, Wilcoxon). There was a tendency for blood pressure to fall in the study patients (not significant) but graft blood flow still increased from 98 ml min(-1) (41-221) to 160 ml min(-1) (101-250), compared to flow in the control patients of 101 ml min(-1) (45-176) at baseline to 104 ml min(-1) (56-168; p < 0.01) at 20 min. Conclusions: Epidural anaesthesia significantly decreases peripheral resistance and increases graft blood flow in femorocrural grafts and would appear, therefore, to be of benefit for patients undergoing femorodistal reconstruction.