RS20 - Peripheral Nerve Blocks and Opioid Utilization in Patients Undergoing Lower Extremity Bypass within an Enhanced Recovery Program

Objectives: Despite national efforts to reduce opioid prescribing, post-operative opioid utilization remains high. Vascular surgery patients are particularly vulnerable to opioid dependence, making targeted interventions critical1. Enhanced Recovery Programs (ERP) recommend multimodal analgesia and peripheral nerve blocks (PNB) as strategies to improve peri-operative pain control2,3. This study evaluated the relationship between PNB use and opioid utilization in patients undergoing lower extremity bypass (LEB) within a standardized ERP.

Methods: A retrospective single-institution review was performed of patients undergoing LEB for non-traumatic indications between 2021 and 2024. All patients were enrolled in a LEB-ERP, which recommends pre-operative PNB. Blocks were omitted only for patient refusal, proceduralist discretion, or contraindication due to antiplatelet/anticoagulation therapy. Primary endpoints are utilization rate of pre-operative PNB, post-operative inpatient opioid utilization, and discharge opioid utilization. Opioid doses are reported as Morphine Milligram Equivalents (MME) Secondary outcomes include length-of-stay (LOS) and compliance with the Delphi-Consensus on opioid prescribing for vascular surgeons.

Results: A total of 256 patients were included. Most presented with chronic limb-threatening ischemia (CLTI, 83.6%) and 43.6% underwent tibial bypass. Nearly half (49.2%) had an opioid prescription prior to surgery, more frequently among CLTI patients compared to non-CLTI (53.8% vs 35.0%, p=0.024). PNBs were performed in 84% of cases. PNB use decreased from 87.3% in 2021 to 80.2% in 2024. There were no baseline demographic differences between patients that did and did not receive PNB. PNB use was associated with significantly shorter post-operative LOS (6.5±6.0 vs 8.4±7.4 days, p=0.031). LOS increased over the study period (5.9 to 8.4 days), paralleling the decline in block use. Mean daily in-hospital opioid use was 82.9 MME, and patients were discharged with an average of 248 MME, both of which increased across study period. PNB use was associated with significantly less daily MME in patients with pre-existing opioid prescriptions (81.6 vs 110.8, p=0.015). Pre-existing pre-operative opioid prescriptions, CLTI, and prior ipsilateral interventions were associated with significantly higher opioid requirements. Prescribing patterns were in compliance with Delphi Consensus recommendations in 60% of patients.

Conclusions: Opioid utilization after LEB remains variable and high despite ERP implementation, underscoring the need for further standardization. PNB use was associated with shorter LOS and reduced opioid use among chronic opioid users, but block utilization declined during study period, coinciding with rising opioid use and LOS. These findings support impact of PNB on important care metrics and a need for renewed efforts to standardize PNB use and opioid prescribing for LEB patients.