Clinical benchmarks regarding multimodal peripheral nerve blocks for postoperative analgesia: observations regarding combined perineural midazolam-clonidine-buprenorphine-dexamethasone.

Abstract

In a separate commentary [1], we reported on potential clinical research priorities with respect to multimodal perineural anesthesia and analgesia (MMPNA). This was based on our group's review of institutional quality assurance/improvement (QA/QI) data routinely using this technique for over 1,300 patients from late 2011 to the present at the Veterans Affairs Pittsburgh Healthcare System. This previous commentary addressed the four-drug combination of bupivacaine, clonidine, buprenorphine, and dexamethasone (BPV-CBD) used for postoperative perineural analgesia (e.g., combined with intraoperative spinal anesthesia), or for the dual role of intraoperative perineural anesthesia and postoperative analgesia. The average block duration (block insertion time until peak rebound pain score on a 0 to 10 scale) in this previous commentary was 33 to 37 hours, depending on the context. We believe that this clinical observation warrants high-priority research for the specialty, especially in the context of the effects of buprenorphine dose response and the parameters of block duration and rebound pain. In this current commentary, we will direct separate attention toward the four-drug combination of midazolam (MDZ) with CBD used for specific contexts of motor-sparing perineural analgesia. Both BPV-CBD and MDZ-CBD four-drug nerve block combinations were shown to be safe in vivo, as reported in a separate manuscript [2] in this issue of Pain Medicine . Based on the previously reported in vitro safety of MDZ-CBD [3], we used MDZ-CBD blocks in selected cases where the risk of motor block (and subsequent falls) was deemed as high as the potential short- and long-term risks of escalating systemic opioid analgesia (and/or intraoperative conversion to general endotracheal anesthesia [GETA]). All patients were fully informed before the use of MDZ-CBD as an “off-label” good-faith effort to 1) avoid motor block (i.e., routinely resulting from perineural bupivacaine use with or without perineural CBD use); 2) avoid GETA; and …