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 supineavoidance therapies are inherently uncomfortable, and treatment adherence is poor and diffi cult to monitor objectively. This study evaluated the effi cacy 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 (effi cacy study). Patients: 17 patients undergoing in-laboratory sleep studies (validation) and 15 patients with supine-predominant OSA (effi cacy). Interventions: Effi cacy 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 classifi cations 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 effi cacy 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.

The undervalued potential of positional therapy in position-dependent snoring and obstructive sleep apnea—a review of the literature

“…In 1998, Marklund et al [28] defined supine-dependent sleep apnea as follows: a supine apnea–hypopnea index ≥10, together with a lateral apnea–hypopnea index <10. In the study of Bignold et al [29], when patients met the following criteria, they were deemed position-dependent: “overall AHI ≥15/h, supine AHI ≥ twice the non-supine AHI; ≥20 min of sleep in supine and non-supine postures and non-supine AHI <15.”…”

“…The worst sleeping position is usually, but not always, the supine position [35]. Various techniques are described to prevent patients from assuming the supine position such as positional alarms, verbal instructions, tennis balls (TBT), vests, “shark fins,” or special pillows [7, 27, 29, 40–53]. …”

“…Loord and Hultcrantz [44] reported that half of the patients ( n  = 18) treated with PT (soft vest attached to a board with pillow) snored more frequently; specifically, six snored less frequently, nine snored more frequently, and for two, there was no difference. A recent study by Bignold et al [29] reporting on the efficacy of the position monitoring and supine alarm device on 15 patients with supine-dependent OSA found no improvement in snoring. There was a trend for an overall reduction in snoring frequency, but this was not statistically significant.…”

“…Various techniques are described to prevent patients from assuming the supine position, such as an upright sleep posture, positional alarms, verbal instructions, TBT, vests, “shark fins,” or special pillows [7, 27, 29, 40–53]. …”

“…Bignold et al [29] evaluated the efficacy of a similar device in 15 patients fulfilling the following criteria: overall AHI ≥15 per hour, supine AHI twice or greater than the non-supine AHI; ≥20 min of sleep in supine and non-supine postures and non-supine AHI < 15. Subjects were assigned to receive the active PT or the inactive PT in a random order for a week followed by a 1-week washout before commencing the alternative treatment.…”