brief survey before receiving their CPAP devices. 72 of 94 participants repeated the survey after they used their CPAP devices for 30 -90 days. 94 data of CPAP adherence were downloaded from each participant's CPAP device. Results: Using the enter method of multiple regression analysis, we found from: (1) the survey of pre-CPAP therapy, the level of PSH-BI explained a significant amount of the variance in CPAP adherence, R 2 = .066, R 2 adjusted = .046, F(2, 91) = 3.27, ρ < .05. Although the level of PSB did not significantly predicted CPAP adherence (β = -.071, t(91) = -.688, ns), the level of BI significantly predicted CPAP adherence (β = .249, t(91) = 2.456, ρ < .05); (2) the survey of post-CPAP therapy, the level of PSH-BI explained a significant amount of the variance in CPAP adherence, R 2 = .213, R 2 adjusted = .190, F(2, 69) = 9.34, ρ < .01. Both levels of PSB and BI significantly predicted CPAP adherence (β = -.262, t(69) = -2.268, ρ < .05; β = .381, t(69) = 3.561, ρ < .01, respectively).
Introduction:The pathophysiology of apneas is distinct from that of hypopneas. Apneas reflect static obstruction with absent flow, while hypopneas reflect dynamic obstruction with decreased flow. We propose that hypopneas and respiratory-effort related arousals (RERAs) are eliminated with lower positive airway pressure (PAP) than apneas, and both higher HAR and higher RAR (RERA+hypopnea/apnea ratio) are associated with lower optimum PAP due to a lower critical closing pressure (Pcrit). Methods: We performed a retrospective chart review in a sample of 150 consecutive adult patients with obstructive sleep apnea hypopnea syndrome (OSAHS), defined by a total Respiratory Disturbance Index (tRDI) of ≥ 5 apneas, hypopneas, and RERAs per hour of sleep. Polysomnography was scored using AASM 2016 Version 2.3 guidelines using both option 1a (tRDI) and 1b (apnea hypopnea index [AHI]) criteria. Polysomnographic data were collected; HAR and RAR were calculated. The primary outcome was a correlation between HAR and RAR and optimum PAP, where HAR and RAR were the main independent variables, and the level of optimum PAP was the main outcome variable. Data were analyzed using a 2-tailed Student's t-test for continuous variables. The level of statistical significance was defined as p < 0.05. Results: Among 76 men and 74 women aged 54.7 ± 14.2 years with a mean body mass index (BMI) of 37.6 ± 11.5 kg/m 2 and a mean AHI of 30.2 ± 31.3, optimum PAP was significantly lower with higher HAR (p = 0.037) and higher RAR (p = 0.00002). In addition, hypopnea index, AHI, tRDI, and BMI also had a significant direct association with PAP (p < 0.001), while the oxygen saturation nadir had a significant inverse association (p < 0.001). Apnea index and optimum PAP were not significantly related. We also observed a significant association between BMI and both HAR (p < 0.0001) and RAR (p < 0.001). Conclusion: OSAHS with a preponderance of hypopneas and paucity of apneas requires a lower level of PAP, suggesting a distinct pathophysiology of hypopnea-predom...
