The Efficacy of Low-Level Continuous Positive Airway Pressure for the Treatment of Snoring

Abstract

Study objectives: To assess effects of low-level continuous positive airway pressure (CPAP) on snoring in habitual snorers without obstructive sleep apnea (OSA).

Methods: A multicenter prospective in-laboratory reversal crossover intervention trial was conducted between September 2013 and August 2014. Habitual snorers were included if they snored (inspiratory sound pressure level ≥ 40 dBA) for ≥ 30% all sleep breaths on a baseline sleep study (Night 1), and if significant OSA and daytime somnolence were absent. Included participants then underwent a CPAP titration study at 2, 4, or 6 cm H2O (Night 2) to examine snoring responses to step-increases in nasal pressure, a treatment night at optimal pressure (Night 3), followed by baseline night (Night 4). At each pressure, snoring intensity was measured on each breath. Snoring frequency was quantified as a percentage of sleep breaths at thresholds of 40, 45, 50, and 55 dBA. Sleep architecture and OSA severity were characterized using standard measurements.

Results: On baseline sleep studies, participants demonstrated snoring at ≥ 40 dBA on 53 ± 3% and ≥ 45 dBA on 35 ± 4% of breaths. Snoring frequency decreased progressively as nasal pressure increased from 0 to 4 cm H2O at each threshold, and plateaued thereafter. CPAP decreased snoring frequency by 67% and 85% at 40 and 45 dBA, respectively. Intervention did not alter sleep architecture and sleep apnea decreased minimally.

Conclusions: Low-level CPAP below the range required to treat OSA diminished nocturnal snoring, and produced uniform reduction in nightly noise production below the World Health Organization's limit of 45 dBA.

Clinical trial registration: ClinicalTrials.gov, identifier: NCT01949584.

Keywords: CPAP; noise pollution; sleep; sleep apnea; snore.

© 2017 American Academy of Sleep Medicine

Figures

Figure 1. Image of customized butterfly nasal interface with custom noise baffling pathway therein.

The interface connects in series with the breathing circuit and flow generator. The breathing circuit wraps around both cheeks toward the crown of the head before connecting to the continuous positive airway pressure hose and flow generator.

Figure 2. Study flow diagram describing screen failures and final study sample.

A two stage screening process was implemented by means of telephone survey and baseline sleep study. For details on “Drop-out,” see Subjects section in text. BMI = body mass index, ESS = Epworth Sleepiness Scale, RDI = respiratory disturbance index.

Figure 3. Recording example illustrating snoring response to low-level CPAP in one habitual snorer during NREM sleep.

Snoring amplitude decreased progressively at 0, 2 and 4 cm H2O. Snoring was associated with the development of IFL, which was abolished at 4 cm H2O. In bottom panel, airflow signals are illustrated in greater detail from shaded regions of compressed signals above at each CPAP level. IFL was present at 0 and 2 cm H2O, as indicated by mid-inspiratory flattening of the airflow signal and an increase in the inspiratory duty cycle, but was abolished at 4 cm H2O. CPAP = continuous positive airway pressure, IFL = inspiratory airflow limitation, NREM = non-rapid eye movement, SaO2 = oxyhemoglobin saturation.

Figure 4. Snoring frequency (as a percentage of all breaths during sleep) versus CPAP level during the titration Night 2 for the entire group at threshold levels of 40 and 45 dBA.

** = P < .005 treatment versus initial baseline. *** = P < .001 treatment versus initial baseline. CPAP = continuous positive airway pressure.

Figure 5. Snoring frequency during the low-level CPAP treatment (Night 3) and untreated baseline nights before and after treatment (Nights 1 and 4) for the entire group at threshold levels of 40, 45, 50, and 55 dBA.

*** = P < .001 treatment versus initial baseline and follow-up. ### = P < .001 treatment versus initial baseline and follow-up. §§§ = P < .001 treatment versus initial baseline and follow-up. ^^ = P < .01 treatment versus initial baseline and follow-up. CPAP = continuous positive airway pressure.