Contraindications to use of neuraxial anesthesia for lower limb revascularization surgery in adults: a cross-sectional study.

Abstract

Nonrandomized and some randomized data suggest neuraxial anesthesia may improve outcomes after lower limb revascularization surgery. Nevertheless, the prevalence of contraindications to neuraxial anesthesia in vascular surgery patients is unknown. We aimed to identify the prevalence of patients with contraindications to neuraxial anesthesia, and to derive and validate a case ascertainment algorithm identifying individuals likely to have contraindications. We conducted a historical cross-sectional study of open lower limb revascularization surgeries performed between 2019 and 2021 at The Ottawa Hospital. Medical records were reviewed for demographic data, admission, procedural characteristics, and presence of contraindications to neuraxial anesthesia. Case ascertainment algorithms to predict the presence of absolute contraindications to neuraxial anesthesia were derived and internally validated. We identified 340 cases. General anesthesia was used in 219 (64.4%) cases, isolated neuraxial (spinal and/or epidural) in 106 (31.2%) cases, and general plus neuraxial in 15 (4.4%) cases. Seventy-eight (22.9%; 95% confidence interval [CI], 18.8 to 27.7) patients had absolute contraindications to neuraxial anesthesia, primarily because of anticoagulation or antiplatelet medication (89.4%); 21 (6.2%; 95% CI, 4.1 to 9.3) had relative contraindications, primarily long anticipated duration of surgery (16/21, 76.2%). We derived and validated three nested case-ascertainment algorithms. Using admission and procedure variables, discrimination was moderate with moderately explained variance, and calibration was inadequatefor reliable use. Patient comorbidity and laboratory data did not improve algorithm performance. Most patients undergoing lower limb revascularization surgery did not have absolute contraindications to neuraxial anesthesia. When present, contraindications typically related to anticoagulation. Admission, procedure, comorbidity, and laboratory data did not provide adequate accuracy to ascertain contraindication status.