Anesthesia Type Does Not Influence Mortality in Below the Knee Amputation in a National Veteran Cohort

Abstract

It is generally accepted that anesthesia selection conveys no differential risk in mortality or adverse cardiac outcomes for lower extremity amputations. Recent large-scale studies in combined lower extremity amputations as well in below the knee amputation (BKA) patients specifically have found that general anesthesia corresponds to increased perioperative blood utilization. In examining a small cohort of BKA patients at our own institution, we did not find this association. We set forth to investigate anesthesia-related trends in BKA outcomes across the national veteran population utilizing the Veteran’s Affairs Surgical Quality Improvement Program database. With IRB approval, a retrospective review of the Veteran’s Affairs Surgical Quality Improvement Program database was undertaken for all patients in the Veteran’s Affairs Health System who underwent BKA from 1999 to 2018. Patients were divided into two groups; those undergoing the BKA procedure under general anesthesia (G-A) versus other anesthesia approaches (regional, spinal, epidural, nerve block; O-A). Data collected included patient demographics, history of comorbid conditions, indication for procedure, mortality, postoperative blood use, and related outcomes. Chi Square with Yates correction, unpaired t-test and odds ratios with 95% confidence interval were determined using a covariate-adjusted binary logistic regression model+ (SPSS software; version 25, IBM Corp; Armonk, NY). There were 27,709 patients (99.0% male) with an average age of 65.0 ± 10.4 years who underwent BKA during the study period. There was no significant difference in average age nor American Society of Anesthesiologists class between groups. G-A was associated with increased return to the operating room, multiple complications, and postoperative sepsis while O-A was associated with increased superficial surgical site infection, wound dehiscence, and postoperative hospital stay. There were no significant differences between groups in terms of 30-day mortality or postoperative blood utilization, myocardial infarction, deep vein thrombosis, cerebrovascular accident, pulmonary embolism nor renal failure. When adjusted for covariates, G-A corresponded to slight but significant increased odds ratios+ for OR Return within 30 days 1.242 (95% confidence interval, 1.165-1.323) and postoperative sepsis 1.331 (95% confidence interval, 1.16-1.588) (Table). Analysis of a large veteran cohort of BKA patients found that mortality, postoperative blood utilization, and rates of postoperative myocardial infarction were not influenced by anesthesia type. General anesthesia was associated with increased odds for postoperative sepsis and 30 day return to the operating room but also with relatively increased postoperative recovery. Practitioners should consider these Results when selecting anesthesia type for patients undergoing BKA procedures.TableAdjusted analysisPostoperative outcomeG-A (n = 19,121)O-A (n = 8,588)P valueReturn to operating room within 30 days5457 (28.5)1997 (23.3).0001aWound dehiscence273 (1.4)155 (1.8).0214aSepsis529 (2.8)182 (2.1).002aLength of stay, days14.4 ± 16.515.0 ± 18.3.007bG-A, General anesthesia; O-A, other form of anesthesia.Values are number (%) or mean ± standard deviation. Open table in a new tab