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OBJECTIVE: Patients undergoing major lower extremity amputation for peripheral arterial disease are often elderly, debilitated, and fraught with medical co-morbid conditions that place them at high risk for surgical intervention. Data from lower extremity revascularization surgeries are often extrapolated to determine which anesthetic modality to use for amputations, with preference given to regional anesthesia. However, there is little evidence to support the use of one mode of anesthesia over the other. We conducted this study to determine the effect of anesthetic modality on the clinical outcomes of patients undergoing above or below knee amputations.
METHODS: This study is a retrospective review of consecutive patients who underwent major lower extremity amputation at a single center between 2002 and 2011. The study population was divided into two groups based on anesthetic modality, regional versus general anesthesia. These groups were compared based on demographics and co-morbidities. Major outcomes analyzed included death, MI, and pulmonary complications. Secondary outcome measures included cardiac arrhythmias, VTE, and length of ICU and Hospital stay.
RESULTS: A total of 463 patients were identified of which 56 patients were excluded for incomplete data, leaving 407 patients. Of these, 259 patients underwent amputation under regional anesthesia and 148 under general. Patients in the regional anesthesia group were older (76.6 years vs 71.6 years, P=0.001) and had a lower BMI (25.2 vs 26.9, P=0.013). They were also less likely to be on pre-operative anti-platelet therapy (ASA/Plavix) or anticoagulation (27% vs 45%, P=0<001). Regional anesthesia was associated with a lower incidence of post operative pulmonary complications (14% vs 45%, P=0.022) and post-operative arrhythmias (14% vs 25%, P=0.006). Length of stay in the ICU (1.92 days vs 3.85 days, P=0.001) and hospital (19.4 days vs 23.1 days, P=0.037) were significantly higher in the group receiving general anesthesia. No significant differences in postoperative MI (12% vs 9%, P=NS), VTE (5% vs 7%, P=NS) or mortality (10% vs 13%, P=NS) was seen between groups. Controlling for procedure, AKA vs BKA, did not significantly alter these results.
CONCLUSIONS: Regional anesthesia for patients undergoing lower extremity amputation is associated with a lower incidence of post-operative pulmonary complications and arrhythmias. It is also associated with lower resource utilization. It should be the preferred modality of anesthesia for patients undergoing major lower extremity amputation.