Up-down studies: responding to dosing!

Since the publication of the first use of up-down sequential allocation in regional anaesthesia and the description of the minimum local analgesic concentration (MLAC) model in 1995, the model has been extensively replicated and adapted to a variety of clinical and pharmacologic research issues. Now that a decade has passed, it seems appropriate for us to consider the contribution that these studies have made to our understanding of the pharmacodynamics of regional anaesthesia. In doing this, the authors debate the issues with MC briefly describing the methodology and then advancing the pro’ position and RD the con’. What follows are our attempts to keep the reader as fully appraised and hopefully interested as possible.