Dexamethasone or Dexmedetomidine Adjuvants to Peripheral Nerve Blocks for Total Knee Replacement

Abstract

Problem and Purpose: At a community hospital, Total Knee Arthroplasties (TKAs) comprise 6.5% of all scheduled procedures, approximately 40 per month. Adequate postoperative pain control is critical for avoiding complications. The adductor canal block (ACB) and the interspace between the popliteal artery and capsule of the knee (IPACK) peripheral nerve blocks (PNBs) control postoperative pain; however, they only last 12–18 hours. Addition of dexamethasone or dexmedetomidine to local anesthetics used for PNBs have been identified to prolong their duration and improve postoperative pain control. The purpose of this project was to implement a guideline on additions of dexamethasone or dexmedetomidine to ACB and IPACK PNBs for TKAs to prolong the PNB for pain control. Methods: A guideline regarding use of dexamethasone and dexmedetomidine was created with input from anesthesia leadership. The anesthesia staff were educated during a staff meeting, the guideline was posted in operating rooms, and staff started adding either adjunct medication to the local anesthetic used for PNBs for TKAs. Over a 15-week period, compliance with the guideline was measured, along with pain scores in the post anesthesia care unit, 8, 16, 24 hours, or until discharge after a 23-hour observation. Data was collected weekly and analyzed using a run chart and descriptive statistics. Exclusion criteria were revision TKA, anxiety or depression on medication, and chronic pain on home opioids. Results: 94 patients were included. 38.9% of patients receiving PNBs had dexamethasone added (n=37). No PNBs used dexmedetomidine. 61.1% of PNBs did not have any adjunct added (n=58). 30.8% of patients had severe pain scores postoperatively (n=29). 24.2% of patients with severe pain had dexamethasone added (n=7). Median compliance with guideline use was 28%. Conclusions: There was no association with the implementation of the guideline and increased use of adjunct medications. Patients who received dexamethasone hadless incidence of severe pain. Addition of dexamethasone to PNBs is a low-cost way to improve pain scores postoperatively. Less severe pain scores improve patient satisfaction and removes a barrier to mobilization, reducing incidence of postoperative complications.