A pilot evaluation of a nasal expiratory resistance device for the treatment of obstructive sleep apnea

Abstract

Background: Obstructive sleep apnea (OSA) is a major problem in need of new treatment approaches. The present pilot study tests the hypothesis that the application of expiratory resistance via a nasal valve device would improve breathing during sleep in subjects with OSA and in primary snorers.

Methods: Thirty men and women were recruited from the community and from the Stanford University Sleep Disorders Clinic. Twenty-four had at least mild OSA (AHI >5), and 6 were primary snorers. Subjects underwent 2 nights of polysomnographic evaluation, one with and one without a new nasal resistance device with the order of nights counterbalanced across participants. The device consisted of a small valve inserted into each nostril calibrated to provide negligible inspiratory resistance, but increased expiratory resistance with a back pressure between 60 and 90 cm H2O*sec/Liter (at 100 mL/sec flow). Standard polysomnography was conducted to compare participants' sleep both with and without the device, with the scoring conducted blind to treatment condition.

Results: The apnea-hypopnea (AHI) (p < 0.001) and oxygen desaturation (O2DI) (p < 0.01) indices both significantly decreased, and the percentage of the night spent above 90% saturation (p < 0.05) significantly increased with device use. The observed amount of snoring (p < 0.001) was significantly decreased with device use, and there were no significant changes in measures of sleep architecture.

Conclusions: The results of this pilot study are suggestive of a therapeutic effect of expiratory nasal resistance for some OSA patients and indicate that this technique is worthy of further clinical study.

Figure 1

Schematic (upper left panel) and photograph (upper right panel) of the expiratory resistance device showing the various parts and relative size. Photograph of a single device positioned as per the study (lower left panel).

Figure 2

Histogram of the apnea-hypopnea index shown on treatment and control nights for the 6 severe subjects (untreated AHI between 32.5 and 83.8), the 7 moderate subjects (untreated AHI between 16.2 and 26.5), the 11 mild subjects (untreated AHI between 5.1 and 14.7) and the 6 primary snoring subjects (untreated AHI values <5). Data are presented as group means with error bars representing the standard error scores. There was a significant difference between treatment and control nights in the mild, moderate, and severe OSA groups, p < 0.001.

Figure 3

Histogram of the oxygen desaturation index shown on treatment and control nights for the 6 severe subjects, the 7 moderate subjects, the 11 mild subjects, and the 6 primary snoring subjects (untreated AHI values <5). Data are presented as group means with error bars representing the standard error scores. There was a significant difference between treatment and control nights in the mild, moderate, and severe OSA groups, p < 0.01.