228 | Chapter 9 Limitations This is a small randomized and single-blinded exploratory study in which only selfreported active, predominantly male, laryngectomized patients have been included. Not blinding the researcher administering the test to the HME in use could have introduced performance bias. However, maximal encouragement was part of the standard operating procedure of the CPET. In addition, if a Pygmalion effect has occurred, this would likely have biased the findings towards better achievement using the lower resistance HME. Since we did not observe a difference, we deem such bias unlikely. The results should not be extrapolated to the larger population of laryngectomized patients. Since a comparison of the influence of regular HME resistance on exercise performance was beyond the scope of the study, there is no equal distribution of the two types of regular HMEs. As a pilot study, the study was not powered for statistical testing of differences. Hence, our findings and interpretation should be considered with caution. Lung function tests were not performed pre-CPET. In hindsight, this would have been useful to obtain a better assessment of pulmonary function as a potentially limiting factor.
RkJQdWJsaXNoZXIy MTk4NDMw