Improved Automatic CPAP Algorithm to Treat Obstructive Sleep Apnea (OSA)

Study Overview
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Brief Summary
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The purpose of this study is to compare a modified AutoSet algorithm running on research hardware versus the traditional AutoSet algorithm running on an S7 AutoSet Spirit. The study will determine if the modified AutoSet algorithm reacts appropriately to obstructive apnoeas and hypopnoeas and provides suitable levels of positive airway pressure compared to the S7 AutoSet Spirit. The hypothesis is that the modified AutoSet algorithm will be more efficacious than the traditional AutoSet algorithm

Detailed Description
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Subjects in the trial will spend 2 nights in a sleep laboratory being monitored with a full montage polysomnograph (PSG) with each of the algorithms providing positive airway pressure therapy. The PSG records EEG, EMG, EOG, patient airflow, respiratory effort, blood oxygen saturation, and body position. In a randomised order each subject will spend one night being treated by the modified AutoSet algorithm and a second night being treated by the traditional AutoSet algorithm. The subjects will be blinded to which therapy they are receiving and the scorer of the PSG will also be blinded to which therapy is being used.

Official Title
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Study of an Improved Automatic CPAP Algorithm for the Treatment of Obstructive Sleep Apnea

Conditions
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Obstructive Sleep Apnea (OSA)

Intervention / Treatment
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* Device: Modified AutoSet Algorithm
* Device: Standard AutoSet Algorithm


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: PSG-confirmed diagnosis of OSA, showing an apnoea-hypopnoea index (AHI) of at least 15 events/hr and an obstructive apnoea index (OAI) of at least 5 events/hr. On CPAP therapy (fixed pressure or autoCPAP) for at least 1 month. Using a ResMed mask (this requirement applies only to phase 2 of the trial) without significant discomfort for at least 2 weeks. Age between 18 and 70 years. Written informed consent. Exclusion Criteria: Unstable medical condition, including unstable angina, myocardial infarction within previous 6 months, cardiac failure NYHA grades III and IV, epilepsy, psychiatric disturbance. Respiratory insufficiency, defined as arterial CO2 greater than 50 mm Hg during the daytime or arterial oxygen saturation less than 90% when asleep and breathing room air on effective CPAP therapy. Recent severe epistaxis. History of spontaneous pneumothorax. History of regurgitation of gastric contents during sleep. Unable to give written informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: modified autoset<br>the modified AutoSet responds to different breathing patterns than the standard AutoSet, to treat OSA. Participants in this arm will trial the modified AutoSet for one night, and the standard AutoSet for one night, in a randomised order | Device: Modified AutoSet Algorithm<br>* The modified AutoSet algorithm responds to more patient non-normal flow types than the standard AutoSet algorithm<br>* Other names: Enhanced AutoSet algorithm;Device: Standard AutoSet Algorithm<br>* The standard AutoSet used for treatment of OSA<br>|
| Active Comparator: standard AutoSet<br>The standard autoset treat OSA by using pressure increases to overcome abnormal breathing patterns. Patients in this arm will use the standard AutoSet for one night and the modified AutoSet for one night, in a randomised order | Device: Modified AutoSet Algorithm<br>* The modified AutoSet algorithm responds to more patient non-normal flow types than the standard AutoSet algorithm<br>* Other names: Enhanced AutoSet algorithm;Device: Standard AutoSet Algorithm<br>* The standard AutoSet used for treatment of OSA<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Physiological sleep signals including EEG, Sp02, respiratory effort and nasal flow, will be recorded, analysed and reported in the form of a series of indices, which are the outcome variables of the study. | sleep signals taken from overnight polysomnography recordings | Two consecutive nights |