Systemic Heparinization After Neuraxial Anesthesia in Vascular Surgery: A Retrospective Analysis

Abstract

Objectives: The American Society of Regional Anesthesia and Pain Medicine's guidelines recommend a 1-hour interval after neuraxial anesthesia (NA) before systemic heparinization to mitigate the risk of spinal hematoma (SH). The study authors aimed to characterize the time interval between NA and systemic heparinization in vascular surgery patients (primary outcome). The secondary outcomes included the historic incidence of SH, and risk estimation of the SH formation based on available data. Heparin dose, length of surgery, difficulty and/or the number of NA attempts, and patient demographics were recorded.

Design: A retrospective analysis between April 2012 and April 2022.

Setting: A single (academic) center.

Participants: Vascular surgery patients.

Interventions: Intravenous heparin administration.

Measurements and main results: All (N = 311) vascular patients were reviewed, of whom 127 (5 femoral-femoral bypass, 67 femoral-popliteal bypass, and 55 endovascular aneurysm repairs [EVAR]) received NA and were included in the final analysis. Patients receiving general anesthesia alone (N = 184) were excluded. Neuraxial anesthesia included spinal (N = 119), epidural (N = 4), or combined spinal-epidural (N = 4) blocks. The average time between NA and heparin administration was 42.8 ± 22.1 minutes, with 83.7% of patients receiving heparin within 1 hour of NA. The time between NA and heparin administration was 40.4 ± 22.3, 50.1 ± 23.4, and 31.3 ± 12.5 minutes for femoral-femoral bypass, femoral-popliteal bypass, and EVAR, respectively. Heparin was administered after 1 hour of NA in 20% of femoral-femoral bypass, 27% of femoral-popliteal bypass, and 3.9% of EVAR patients. No SHs were reported during the study period.

Conclusions: The vast majority of vascular surgery patients at the authors' center received heparin within 1 hour of NA. Further studies are required to assess if their findings are consistent in other vascular surgery settings and/or centers.

Keywords: neuraxial anesthesia; retrospective analysis; spinal hematoma; systemic heparin; vascular surgery.