Australian New Zealand Clinical Trials Registry, http://www.anzctr.org.au, trial ID: ACTRN12614000364673.

Study objectives: Oral appliance (OA) therapy is the leading alternative to continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA). It is well tolerated compared to CPAP. However, ≥50% of patients using OA therapy have incomplete resolution of their OSA. Combination therapy with CPAP and oral appliance (CPAP+OA) is a potential alternative for incomplete responders to OA therapy. This study aimed to determine the extent to which combination therapy reduces therapeutic CPAP requirements using gold standard physiological methodology in those who have an incomplete response to OA therapy alone. Methods: 16 incomplete responders (residual AHI> 10events/h) to a novel OA with a built-in oral airway were recruited (3F:13M, aged 31-65 years, BMI: 22-38kg/m2, residual AHI range 13-63events/h). Participants were fitted with a nasal mask, pneumotachograph, epiglottic pressure catheter and standard polysomnography equipment. CPAP titrations were performed during NREM supine sleep in each participant during 3 conditions (order randomized): 1) CPAP only, 2) CPAP+OA(oral airway open), and 3) CPAP+OA(oral airway closed). Results: OSA was resolved at pressures of 4±2 and 5±2cmH2O during CPAP+OA (oral airway open) and CPAP+OA (oral airway closed) conditions versus 8±2cmH2O during CPAP only (P<0.01). Negative epiglottic pressure swings in oral airway open and closed conditions were normalized to CPAP only levels (-2.5[-3.7,-2.6] vs. -2.3[-3.2,-2.4]vs. -2.1[-2.7,-2.3]cmH2O). Conclusions: Combined CPAP and OA therapy reduces therapeutic CPAP requirements by 35-45% and minimizes epiglottic pressure swings. This combination may be a therapeutic alternative for patients with incomplete responses to OA therapy alone and those who cannot tolerate high CPAP levels.

Study Objectives Quantification of upper airway collapsibility in obstructive sleep apnea (OSA) could help inform targeted therapy decisions. However, current techniques are clinically impractical. The primary aim of this study was to assess if a simple, novel technique could be implemented as part of a continuous positive airway pressure (CPAP) titration study to assess pharyngeal collapsibility. Methods A total of 35 participants (15 female) with OSA (mean ± SD apnea–hypopnea index = 35 ± 19 events/h) were studied. Participants first completed a simple clinical intervention during a routine CPAP titration, where CPAP was transiently turned off from the therapeutic pressure for ≤5 breaths/efforts on ≥5 occasions during stable non-rapid eye movement (non-REM) sleep for quantitative assessment of airflow responses (%peak inspiratory flow [PIF] from preceding 5 breaths). Participants then underwent an overnight physiology study to determine the pharyngeal critical closing pressure (Pcrit) and repeat transient drops to zero CPAP to assess airflow response reproducibility. Results Mean PIF of breaths 3–5 during zero CPAP on the simple clinical intervention versus the physiology night were similar (34 ± 29% vs. 28 ± 30% on therapeutic CPAP, p = 0.2; range 0%–90% vs. 0%–95%). Pcrit was −1.0 ± 2.5 cmH2O (range −6 to 5 cmH2O). Mean PIF during zero CPAP on the simple clinical intervention and the physiology night correlated with Pcrit (r = −0.7 and −0.9, respectively, p &lt; 0.0001). Receiver operating characteristic curve analysis indicated significant diagnostic utility for the simple intervention to predict Pcrit &lt; −2 and &lt; 0 cmH2O (AUC = 0.81 and 0.92), respectively. Conclusions A simple CPAP intervention can successfully discriminate between patients with and without mild to moderately collapsible pharyngeal airways. This scalable approach may help select individuals most likely to respond to non-CPAP therapies.