Perineural Dexamethasone Prolongs Adductor Canal Block When Assessed Objectively
Zachary McKee, MD; Sean Dobson, MD, PhD; Daryl Henshaw, MD; Robert Weller, MD;
J. Douglas Jaffe, DO; Christopher Edwards, MD; Wells Reynolds, MD; James Turner, MD
Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC
Section of Regional Anesthesia and Acute Pain Management
Dexamethasone, a glucocorticoid with minimal mineralocorticoid effect, has garnered interest recently as both an intravenous (IV) and perineural (off-label) perioperative analgesic. IV dexamethasone has been shown to be opioid sparing in doses ≥0.1mg/kg , and further research has found both IV and perineural dexamethasone to prolong the duration of peripheral nerve block (PNB). Additionally, a recent systematic review and meta-analysis concluded that the use of perineural dexamethasone as an additive to local anesthetic may prolong the duration of PNB by an additional 3 hours when compared to a PNB and IV dexamethasone combination . Most previous studies have utilized subjective end-points such as time-to-first-analgesic-request, opioid consumption, and patient-determined block duration to measure duration of PNB or analgesia. While these outcomes may all be clinically relevant, they do not necessarily equate to block duration. The aim of this study was to determine whether perineural dexamethasone prolongs an adductor canal block (ACB) when a more objective method of determining block duration is employed. In addition, the study was designed to examine a lower and theoretically safer (perineural use) dose could be equally effective given some concerns that higher than necessary doses of perineural dexamethasone are being utilized . We hypothesized that 1mg and 4mg of perineural dexamethasone would be equally effective at prolonging an ACB when measured objectively by serial pin-prick examination and that both doses would be superior to placebo.
Materials and Methods