Study Objectives:To determine the effects of bilevel positive airway pressure with pressure release technology (Bi-Flex) on adherence and effi cacy in children and adolescents compared to standard continuous positive airway pressure (CPAP) therapy. We hypothesized that Bi-Flex would result in improved adherence but similar effi cacy to CPAP. Methods: This was a randomized, double-blinded clinical trial. Patients with obstructive sleep apnea were randomized to CPAP or Bi-Flex. Repeat polysomnography was performed on pressure at 3 months. Objective adherence data were obtained at 1 and 3 months. Results: 56 children and adolescents were evaluated. There were no signifi cant differences in the number of nights the device was turned on, or the mean number of minutes used at pressure per night for CPAP vs Bi-Flex (24 ± 6 vs 22 ± 9 nights, and 201 ± 135 vs 185 ± 165 min, respectively, for Month 1). The apnea hypopnea index decreased signifi cantly from 22 ± 21/h to 2 ± 3/h on CPAP (p = 0.005), and 18 ± 15/h to 2 ± 2/h on Bi-Flex (p < 0.0005), but there was no signifi cant difference between groups (p = 0.82 for CPAP vs Bi-Flex). The Epworth Sleepiness Scale decreased from 8 ± 5 to 6 ± 3 on CPAP (p = 0.14), and 10 ± 6 to 5 ± 5 on Bi-Flex (p < 0.0005; p = 0.12 for CPAP vs Bi-Flex). Conclusions: Both CPAP and Bi-Flex are effi cacious in treating children and adolescents with OSAS. However, adherence is suboptimal with both methods. Further research is required to determine ways to improve adherence in the pediatric population. keywords: CPAP, obstructive sleep apnea, Bi-Flex Citation: Marcus CL; Beck SE; Traylor J; Cornaglia MA; Meltzer LJ; DiFeo N; Karamessinis LR; Samuel J; Falvo J; DiMaria M; Gallagher PR; Beris H; Menello MK. Randomized, double-blind clinical trial of two different modes of positive airway pressure therapy on adherence and effi cacy in children.