Correlation between change in respiratory muscle strength and cough ability in patients submitted to open-heart surgery

Abstract

The purpose of this study was to determine the correlation between change in respiratory muscle strength and change in cough ability in patients submitted to open-heart surgery. An observational cross-sectional study was conducted among 52 participants. Respiratory muscle strength was assessed by maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) using a respiratory pressure meter. Cough ability was evaluated by voluntary expiratory peak flow (PEF) using a digital spirometer. Evaluations were performed on the day of admission and discharge. Post-operative MIP, MEP, and PEF were significantly lower than those evaluated preoperatively (all p < 0.001). The difference of MIP and MEP was substantial positively correlated with the change in PEF in both absolute and predicted values (all p < 0.001) with the changes in MIP was highly relation. This study demonstrated that weakness of respiratory muscles, especially inspiratory muscle, was correlated to declining in cough ability in patients who had undergone open-heart surgery.