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.

A Prospective Study of 73 Patients to Compare Forward Head Angle, Forward Shoulder Angle, Maximal Inspiratory Pressure, and Self-Reported Breathing-Related Symptoms Before and After Open-Heart Surgery

“…Regarding postoperative angle change, the study also discovered a significant reduction in maximal inspiratory pressure in the postoperative period. The decrease in respiratory muscle strength is associated with intraoperative factors (eg, type of surgery, general anesthesia, medication of heart, cardiovascular bypass, and ventilator use) and postoperative pain [ 11 ]. Injury of the phrenic nerve, which is the main breathing muscle, can occur during cardiac surgery because of the position of the phrenic nerve running from the neck to the upper thorax through the mediastinum to the parietal pleura and fibrous pericardium [ 32 ].…”

“…Therefore, these might be the cause of long-term musculoskeletal and respiratory problems that interfere with the patient’s daily life. Furthermore, several studies have reported changes in patients’ respiratory muscle strength when comparing before and after heart surgery [ 10 , 11 ]. Measuring maximal inspiratory pressure is a simple way of determining inspiratory muscle strength [ 12 , 13 ].…”