To the Editor: The randomized clinical trial by Dr Hulzebos and colleagues1 suggested that preoperative inspiratory muscle training (IMT) may reduce the incidence of postoperative pulmonary complications in high-risk patients undergoing coronary artery bypass graft (CABG) surgery. However, there was important additional detail that was not provided.
First, there was no specification of the measurements of the efficacy of IMT. It was not stated how the recordings of maximal inspiratory and expiratory pressures and of endurance were performed. The recording and interpretation of these outcome measures2 are critical to assess validity of the study. Second, adherence to IMT was only subjectively measured; although the 9 patients in the IMT group who developed pneumonia had trained longer than those who did not, we do not know if they truly had an effective training.
Third, the duration of mechanical ventilation was significantly shorter in the IMT group, which may have influenced the study's primary outcome (postoperative complications and pneumonia in particular) and secondary outcome (the duration of postoperative hospitalization). The weaning process from mechanical ventilation was not standardized, which may have introduced a major bias.
Finally, the authors did not mention the potential risks of IMT. It has been shown in animal studies3 and human studies4 that IMT may be deleterious and may produce injury of the diaphragm, even though it may benefit the external intercostal muscles.5
Financial Disclosures: None reported.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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