“…Although studies of healthy volunteers provide important information, (6,7) how well their findings can be generalized to the population of patients in acute respiratory distress is unclear. Most studies, including the one presented by Holanda, et al, (6) employ a randomized, crossover design where each subject receives each interface studied in a random order, with an interval between each test to allow for washout of the effect from the previous test. (6)(7)(8)(9) The advantage of this design is that the subjects act as their own controls, which has the potential to minimize confounding and also requires fewer subjects in total.…”