To the Editor:
We have just read the article “Upper Airway Collapsibility during Dexmedetomidine and Propofol Sedation in Healthy Volunteers: A Nonblinded Randomized Crossover Study,”1 and we really appreciate this nice work demonstrating the equal possibility of dexmedetomidine and propofol leading to upper airway obstruction or ventilatory depression. However, we wonder whether the patients in either group were in similar stable condition by the end of first airway assessments, as a run-in period or washout period was not mentioned in this crossover study. Liu et al. found that terminal half-life of dexmedetomidine could be as long as 4.4 h,2 so during the infusion of two sedatives by Lodenius et al., is it possible that the residual sedative effect of dexmedetomidine overlaps with sedation of propofol after overcross, or vice versa? As the total time lasted only 101 min, it would be very useful if the authors could supplement details of crossover for this study.
The authors declare no competing interests.