Accurate position monitoring and improved supine-dependent obstructive sleep apnea with a new position recording and supine avoidance device

Abstract

Study objectives: Approximately 30% of obstructive sleep apnea (OSA) patients have supine-predominant OSA, and simply avoiding supine sleep should normalise respiratory disturbance event rates. However, traditional supine-avoidance therapies are inherently uncomfortable, and treatment adherence is poor and difficult to monitor objectively. This study evaluated the efficacy of a novel, potentially more acceptable position monitor and supine-avoidance device for managing supine-predominant OSA and snoring.

Design and setting: In-laboratory evaluation of position recording accuracy versus video recordings (validation study), and randomized controlled crossover trial of active versus inactive supine-avoidance therapy in the home setting (efficacy study).

Patients: 17 patients undergoing in-laboratory sleep studies (validation) and 15 patients with supine-predominant OSA (efficacy).

Interventions: EFFICACY STUDY: 1 week of inactive and 1 week of active treatment in randomized order, separated by 1 week.

Measurements and results: Agreement between 30-sec epoch-based posture classifications from device versus video records was high (median κ 0.95, interquartile range: 0.88-1.00), and there was good supine time agreement (bias 0.3%, 95%CI: -4.0% to 4.6%). In the efficacy study, apnea-hypopnea index (AHI) and snoring frequency were measured in-home using a nasal pressure and microphone based system during inactive and active treatment weeks. The position monitoring and supine alarm device markedly inhibited supine time (mean ± SEM 19.3% ± 4.3% to 0.4% ± 0.3%, p < 0.001) and reduced AHI (25.0 ± 1.7 to 13.7 ± 1.1 events/h, p = 0.030) but not snoring frequency.

Conclusions: This new position monitoring and supine alarm device records sleep position accurately and improves OSA but not snoring in patients with supine-predominant OSA.

Keywords: Obstructive sleep apnea; positional therapy; sleep position; snoring; supine posture.

Figures

Figure 1

Subject wearing the position monitoring and supine alarm device

Figure 2

Bland-Altman plot of mean versus difference in supine time (ST) between the new position monitoring device and video recordings during in-laboratory diagnostic sleep studies (N = 17) The top and bottom unbroken lines indicate the upper and lower 95% limits of agreement, respectively; the middle unbroken line indicates the mean difference; and the dotted line zero bias.

Figure 3

(A) Percent supine time during inactive, intervening and active supine avoidance treatment weeks in positional obstructive sleep apnea patients (N = 14), *p < 0.001 vs inactive and intervening. (B) Apnea index, hypopnea index, and total AHI (thick error bar) during inactive and active treatment (N = 15). *apnea, hypopnea, and total AHI different vs inactive treatment (p < 0.05). Values are mean ± SEM.

Figure 4

Frequency of soft (≥ 50,