Dexamethasone for nerve blocks: Design matters

Desmet and colleagues upset the apple cart in 2013 with their report that 10mg of systemic dexamethasone appears to prolong the time to first analgesic request as much as perineural administration [2]. [...]began a great back-and-forth in the literature, with several studies in various paradigms reporting either superiority of perineural dexamethasone to intravenous or no difference. [...]we will tackle the question of why we see such divergent results in these studies. Should one want to test the proposition that systemic dexamethasone has a similar or “equivalent” effect to perineural, and to be able to make such a conclusion, this is the design to choose. Because the delta used to claim equivalence is usually smaller than a difference in a superiority trial, the necessary sample sizes are often larger.