High- and low-intensity expiratory muscle strength training in patients with severe obstructive sleep apnea syndrome using non-invasive mechanical ventilation: A double-blinded, randomized controlled trial.

BACKGROUND

The effects of expiratory muscle strength training (EMST) with different intensity on stages of sleep were not examined in patients with obstructive sleep apnea syndrome (OSAS).

OBJECTIVES

The aim of this study was to compare the effects of high- and low-intensity EMST (H-EMST and L-EMST) on disease severity, sleep stages, disease-related symptoms, daytime sleepiness, fatigue severity, and sleep quality in adult patients with severe OSAS using non-invasive mechanical ventilation (NIMV).

METHODS

Thirty-one clinically stable patients with severe OSAS were included in this prospective, randomized controlled, double-blinded study. These were randomly divided into two groups. The H-EMST group underwent training at 60% of maximum expiratory pressure (MEP) and the L-EMST group at 30% of MEP, seven days a week for eight weeks. Apnea hypopnea index (AHI), sleep stages, and respiratory sleep parameters were recorded using polysomnographic sleep analysis.

RESULTS

AHI decreased by 34.57% and 20.20% in the H-EMST and L-EMST groups, respectively. A statistically significant improvement in disease severity classifications distributions was observed in the H-EMST group after training (p = 0.016). A greater number of symptoms improved in the H-EMST. The effects of training on respiratory muscle strength, daytime sleepiness, fatigue perception, and sleep quality levels were comparable between the two groups (p>0.05).

CONCLUSIONS

H-EMST training is more effective in reducing disease severity and disease-related symptoms than L-EMST. Further studies are warranted for evaluating the long-term effects of EMST with larger sample sizes in OSAS.