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Study Objectives: To determine the life span of devices in a government long-term continuous positive airway pressure (CPAP) device loan program. Methods: Retrospective review of CPAP devices provided under theQueensland Health Sleep Disorders programin Queensland, Australia, fromdata recorded in an in-house database that has collected data since 1995. Primary outcomes were hours of use and age of device at end-of-life. Device survival analysis was performed collectively for all devices and for different models. Reasons for device end-of-life were compared between models. Results: There were 9,222 CPAP devices provided on long-term loan over this period, with asset end-of-life date available in 90%. Median life span was 15,178 hours (interquartile range 8,167-20,296 hours) and 12.4 (interquartile range 7.6-18.8) years. Five percent of devices were condemned in the first 3 years, and 13% of devices were condemned in the first 5 years. There were significant differences in survival patterns between different models, but after correction for run hours, only one model differed (related to manufacturer policy to replace not repair equipment). Reasons for end-of-life differed between models (P < .001) with manufacturer recall, excessive noise and faulty buttons the most common reasons. Conclusions: GovernmentCPAP loan programs can develop assetmanagement planswith an anticipated average asset life span of 15,178 hours or 12.4 years; however, they should also plan for the need to replace equipmentwhere earlier failure occurs. Early equipment failures are seen with variability between models, and appropriate warranty periods to cover these early failures should be negotiated with manufacturers.

Study Objectives: Obstructive sleep apnea (OSA) is a chronic disease with significant health implications and adequate adherence to continuous positive airway pressure (CPAP) is essential for effective treatment. In many chronic diseases, health literacy has been found to predict treatment adherence and outcomes. In this study, the aim was to determine the health literacy of a sleep clinic population and evaluate the association between health literacy and CPAP adherence. Methods: A prospective cohort study was undertaken, recruiting 104 consecutive patients with a variety of sleep diagnoses. The Short Form Rapid Estimate of Adult Literacy in Medicine (REALM-SF), a validated questionnaire, was administered to measure health literacy. In a sub-group of 91 patients prescribed CPAP for OSA, CPAP usage was measured, with adequate usage defined as greater than 4 h/night CPAP therapy. Results: Seventy-one percent of the sleep clinic cohort was found to have adequate health literacy, as measured by the REALM-SF. In those prescribed CPAP for OSA, inadequate health literacy was associated with a twofold increased risk for inadequate CPAP usage (adjusted odds ratio [OR] 2.9, 95% CI: 1.1 to 8.22, p = 0.045). There was a 1.7 h/night difference in median CPAP usage comparing those with adequate to inadequate health literacy (4.6 h vs. 6.3 h/night). Conclusions: The majority of this sleep disorders cohort had adequate health literacy as measured by the REALM-SF questionnaire. However, inadequate health literacy appears to be an independent predictor of treatment adherence and may represent a modifiable risk factor of poor treatment outcomes in OSA.

BACKGROUND: Double-triggering is a well-recognized form of patient-ventilator asynchrony in noninvasive ventilation (NIV). This benchtop simulated lung study aimed to determine under which patient and device-specific conditions double-triggering is more prevalent, and how this influences the delivery of NIV. METHODS: Two commonly used proprietary NIV devices were tested using a benchtop lung model. Lung compliance, airway resistance, respiratory effort, and breathing frequency were manipulated, and the frequency of double-triggering was assessed. A lung model of very low lung compliance (15 mL/cm H2O) was then used to assess the frequency of double-triggering when breathing frequency and respiratory effort were varied, along with basic NIV settings, including inspiratory pressure and expiratory pressure. Minute ventilation and total inspiratory work (as calculated by the simulated lung model) were also correlated with frequency of double-triggering. RESULTS: In both devices, double-triggering was observed with reduced lung compliance (P =.02 and P <.001 for the two devices, respectively). Reduced airway resistance was associated with double-triggering with the one device only (P =.02). Respiratory effort and breathing frequency were not independent predictors of double-triggering across all lung models. In the lung model of very low lung compliance, both devices showed increased double-triggering at a lower breathing frequency (P <.001 and P <.001), higher respiratory effort (P =.03 and P <.001), and greater pressure support (P =.044, P <.001). Importantly, double-triggering was associated with reduced minute ventilation (P =.007) with one device and increased inspiratory work (P <.001) with the other device. CONCLUSIONS: Both simulated-patient and device characteristics influenced the frequency of double-triggering in NIV, resulting in meaningful consequences in a simulated lung model.

In treating obstructive sleep apnea (OSA), the use of oronasal masks with continuous positive airway pressure (CPAP) has been reported to increase pressure levels and reduce compliance. These reports come mostly from large observational studies. In this study, we examined the impact that oronasal masks have on 95th centile pressures, the residual apnea-hypopnea index (AHI) and compliance compared with nasal masks. A randomised crossover design was implemented. Participants already established on CPAP were randomly allocated to a nasal mask or oronasal mask with auto-titrating positive airway pressure (APAP) for 2 weeks. Participants then crossed over to use the alternate mask for another 2 weeks. Seventy-one participants were recruited but only 60 completed the trial. There were no differences in median 95th centile pressure (nasal, 11.5 cm H2O; oronasal, 11.7 cm H2O; p = 0.115), median residual AHI (nasal, 4.9 events/hr; oronasal, 5.3 events/hr; p = 0.234) or median compliance (nasal, 7.3 hr/night; oronasal, 7.3 hr/night; p = 0.961). Only four patients had 95th centile pressures that were at least 1.5 cm H2O greater with oronasal masks. Oronasal masks do not systematically increase therapeutic CPAP requirements. Rather, a small subset of patients display significant differences in CPAP levels.