This observational study is being undertaken as a part of a Master of Research (MRes) in Clinical Research programme. Its goal is to learn about how continuous positive airway pressure (CPAP) therapy changes the complexity of body signals in adults with obstructive sleep apnoea (OSA). The main question it aims to answer is: \- How does the complexity of physiological signals (specifically oxygen saturation, heart rate, and heart rate variability) change in adults with OSA from before to after three and six months of CPAP treatment? It will use data from individuals who took part in an earlier trial, called 3DPiPPIn, which tested the use of 3D-printed, customised masks CPAP masks through sleep studies.
The purpose of this MRes student study is primarily to examine how the entropy, or complexity as measured by entropy, of physiological signals changes in patients with obstructive sleep apnoea (OSA) in response to continuous positive airway pressure (CPAP) therapy. It is a secondary analysis of data from 3DPiPPIn, a randomised control trial investigating the feasibility of using 3D-printing to develop customised masks for patients receiving positive airway pressure (PAP) therapy. The hypothesis for this study is that entropy-based measures derived from physiological signals will exhibit changes following CPAP therapy, when compared to pre-therapy measures, reflecting the modulation and restoration of physiological systems that were previously disrupted by OSA.
Study Type
OBSERVATIONAL
Enrollment
139
The intervention of interest within this secondary analysis study is Continuous Positive Airway Pressure (CPAP) Therapy, a device-based treatment used to maintain airway patency in patients with sleep-disordered breathing. As a retrospective study, participant exposure to CPAP occured exclusively within the original 3DPiPPIn trial.
Royal Free Hospital
London, United Kingdom
King's College London
London, United Kingdom
Change in oxygen saturation entropy from pre to six months post CPAP therapy
Time frame: From baseline to six months post-initiation of CPAP therapy
Change in heart rate entropy from pre to six months post CPAP therapy
Time frame: From baseline to six months post-initiation of CPAP therapy
Change in heart rate variability entropy from pre to six months post CPAP therapy
Time frame: From baseline to six months post-initiation of CPAP therapy
Change in oxygen saturation entropy from pre to three months post CPAP therapy
Time frame: From baseline to three months post-initiation of CPAP therapy
Change in heart rate entropy from pre to three months post CPAP therapy
Time frame: From baseline to three months post-initiation of CPAP therapy
Change in heart rate variability entropy from pre to three months post CPAP therapy
Time frame: From baseline to three months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and oxygen saturation entropy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and heart rate entropy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and heart rate variability entropy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and oxygen saturation entropy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and heart rate entropy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and heart rate variability entropy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
Time frame: From baseline to three and/or six months post-initiation of CPAP therapy
Nocturnal hypoxia (T90%)
T90% will be calculated as the percentage of total sleep time during which oxygen saturation is below 90%. T90 values will be categorised according to predefined thresholds to characterise the severity of nocturnal hypoxia.
Time frame: At baseline, three months and/or six months post-initiation of CPAP therapy
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