The development of pictorial tools for obstructive sleep apnoea syndrome

Introduction: Obstructive sleep apnoea syndrome (OSAS) is common but remains underdiagnosed and is linked with several disease states and increased risk of mortality. The key symptom, excessive daytime sleepiness, is commonly measured with the Epworth Sleepiness Scale which is not always easily completed by patients. The aim of this thesis is to develop pictorial material for assessing sleepiness and risk of OSAS. Methods: Health literacy was measured in a sample sleep population and the Epworth Sleepiness Scale was investigated for ease of use. Images were developed to translate the Epworth into pictures and the response to pictures of ‘driving while sleepy’ was investigated in detail. A new tool, the pictorial Sleepiness and Sleep Apnoea Scale, was devised by adding four sleepiness images from the pictorial Epworth to four new images representing ‘risk of OSAS’. Evaluations were made in two populations of the tool’s potential in predicting those at risk of OSAS. Results: Poor or impaired health literacy was found in 16% of patients attending the sleep clinic. Evaluation of the Epworth Sleepiness Scale found that a third of new patients made quantifiable errors. A preference for the pictorial Epworth Sleepiness Scale was reported by 55% of users and a kappa statistic indicated good agreement between the pictorial and traditional Epworth Sleepiness Scale. Drivers were more inclined to record feeling sleepy if the image in Q8 depicted the sleepy person in the car as a passenger. In a sleep clinic population the pictorial Sleepiness and Sleep Apnoea Scale was slightly better at predicting disease than the Epworth. In a cardiac rehabilitation clinic use of the witnessed apnoea image from the pictorial Sleepiness and Sleep Apnoea Scale, along with the Epworth Sleepiness Scale, helped to identify symptoms suggestive of sleep apnoea in a third of those screened. When investigated with a sleep study, the prevalence of sleep–disordered breathing in this patient group was 14.8%. Conclusion: Pictorial tools for patients with potential obstructive sleep apnoea syndrome have clinical value and can help bridge the gap between poor or impaired health literacy and the material we use to assess sleepiness and likelihood of obstructive sleep apnoea syndrome.Open Acces

Influence of neighbourhood‐level crowding on sleep‐disordered breathing severity: mediation by body size

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113768/1/jsr12305.pd

Factors affecting daytime function in the sleep apnoea/hypopnoea syndrome

The sleep apnoea/hypopnoea syndrome (SAHS) is characterised by repetitive upper airway obstructions during sleep, which lead to recurrent hypoxaemia and brief arousals from sleep. SAHS patients suffer from excessive daytime sleepiness (EDS), cognitive impairments and decreased psychological well -being. Previous studies have examined relationships between the nocturnal events of SAHS and a limited number of daytime function measures, frequently in small, non -consecutive patient samples. Relationships found have been either weak or non -significant. This thesis examines the relationships between a wide range of nocturnal sleep and breathing variables and daytime function. Additionally, this thesis examines the use of subjective and objective measures of daytime sleepiness, to determine which tests provide the most useful information for SAHS patients.A pilot study found that neither the 103 patients' nor their partners' Epworth rating of sleepiness were strong predictors of SAHS severity. In 150 patients with a wide range of SAHS severity, relationships between nocturnal events and daytime function were examined using newer definitions of arousal and measures of sleep continuity. A broad battery of daytime tests were used including the maintenance of wakefulness test (MWT) and the short form (SF) -36. Unlike previous studies, all correlations were controlled for age and awake oxygen saturation, known to influence the variables measured. The current study also examined these correlations in an unselected patient sample with a range of disease severity. The study found a lack of strong relationships between conventional nocturnal sleep and breathing variables and daytime function. Few baseline variables significantly predicted CPAP use.Daytime function measures were compared within the 150 patients. The multiple sleep latency test (MSLT) and the MWT displayed a moderate, discordant relationship. Measures of cognitive function, psychological well -being and subjective sleepiness ii better related to the MWT than MSLT, suggesting that the MWT may be a more useful tool in assessing functional impairment in sleep apnoea.A randomised cross -over study, on 12 SANS patients, compared daytime sleepiness measured following a night's sleep at home (as performed in this thesis) versus a night in the sleep centre (standard protocol). Preliminary results indicated that daytime sleepiness, as measured by the MSLT and MWT, was not significantly different between the two study limbs. This suggests that the non -standard method of conducting the MSLT and MWT in this thesis does not explain the lack of correlational relationships between nocturnal measures and daytime sleepiness.The studies presented in this thesis demonstrate a lack of identified factors affecting daytime function in a group of unselected SANS patients. This may be due to inter - individual patient variability. Also, more sophisticated nocturnal SANS measures should be examined, as should more `real -life' daytime assessments, such as ambulatory EEG recorded during a patient's normal daily routine

REM-associated sleep apnoea: prevalence and clinical significance in the HypnoLaus cohort

This study determined the prevalence of rapid eye movement (REM) related sleep-disordered breathing (REM-SDB) in the general population and investigated the associations of REM-SDB with hypertension, metabolic syndrome, diabetes and depression.Home polysomnography (PSG) recordings (n=2074) from the population-based HypnoLaus Sleep Cohort (48.3% men, 57±11 years old) were analysed. The apnoea-hypopnoea index was measured during REM and non-REM sleep (as REM-AHI and NREM-AHI, respectively). Regression models were used to explore the associations between REM-SDB and hypertension, diabetes, metabolic syndrome and depression in the entire cohort and in subgroups with NREM-AHI <10 events·h <sup>-1</sup> and total AHI <10 events·h <sup>-1</sup> The prevalence of REM-AHI ≥20 events·h <sup>-1</sup> was 40.8% in the entire cohort. An association between increasing REM-AHI and metabolic syndrome was found in the entire cohort and in both the NREM-AHI and AHI subgroups (p-trend=0.014, <0.0001 and 0.015, respectively). An association was also found between REM-AHI ≥20 events·h <sup>-1</sup> and diabetes in both the NREM-AHI <10 events·h <sup>-1</sup> (odds ratio (OR) 3.12 (95% CI 1.35-7.20)) and AHI <10 events·h <sup>-1</sup> (OR 2.92 (95% CI 1.12-7.63)) subgroups. Systolic and diastolic blood pressure were positively associated with REM-AHI ≥20 events·h <sup>-1</sup> REM-SDB is highly prevalent in our middle-to-older age sample and is independently associated with metabolic syndrome and diabetes. These findings suggest that an increase in REM-AHI could be clinically relevant

Indices from flow-volume curves in relation to cephalometric, ENT- and sleep-O2 saturation variables in snorers with and without obstructive sleep-apnoea

In a group of 37 heavy snorers with obstructive sleep apnoea (OSA, Group 1) and a group of 23 heavy snorers without OSA (Group 2) cephalometric indices, ENT indices related to upper airway collapsibility, and nocturnal O2 desaturation indices were related to variables from maximal expiratory and inspiratory flow-volume (MEFV and MIFV) curves. The cephalometric indices used were the length and diameter of the soft palate (spl and spd), the shortest distance between the mandibular plane and the hyoid bone (mph) and the posterior airway space (pas). Collapsibility of the upper airways was observed at the level of the tongue base and soft palate by fibroscopy during a Muller manoeuvre (mtb and msp) and ranked on a five point scale. Sleep indices measured were the mean number of oxygen desaturations of more than 3% per hour preceded by an apnoea or hypopnoea of more than 10 s (desaturation index), maximal sleep oxygen desaturation, baseline arterial oxygen saturation (Sa,O2) and, in the OSA group, percentage of sleep time with Sa,O2 < 90%. The variables obtained from the flow-volume curves were the forced vital capacity (FVC), forced expiratory and inspiratory volume in 1 s (FEV1 and FIV1), peak expiratory and peak inspiratory flows (PEF and PIF), and maximal flow after expiring 50% of the FVC (MEF50). The mean of the flow-volume variables, influenced by upper airway aperture (PEF, FIV1) was significantly greater than predicted.(ABSTRACT TRUNCATED AT 250 WORDS

Sleep-disordered breathing in patients with implanted cardiac devices: validation of the ApneaScanTM algorithm and implications for prognosis

Aims Sleep-disordered breathing (SDB) is common in heart failure (HF) and frequently undiagnosed. The ApneaScanTM algorithm, available on certain ICD and CRT devices, uses changes in transthoracic impedance with breathing to quantify SDB. This research tests 3 hypotheses: 1) The ApneaScanTM algorithm can accurately detect moderate-to-severe SDB in patients with HF 2) There is minimal night-to-night variability in the ApneaScanTM-determined severity of SDB 3) Those with moderate-to-severe SDB, assessed by ApneaScanTM, have a higher rate of adverse cardiovascular events than those without. Methods Patients with EF≤40% and ICD or CRT devices incorporating ApneaScanTM were recruited. For hypothesis 1, 54 subjects underwent a successful sleep polygraphy study and simultaneous download of ApneaScanTM data. 22 subjects (44%) had undiagnosed moderate-to-severe SDB. The area under the ROC curve was 0.84 for the diagnosis of moderate-to-severe SDB. The optimal ApneaScan cut-off was 30.5/hour (sensitivity 95%, specificity 69%, positive predictive value 68%, negative predictive value 95%). For hypothesis 2, ApneaScanTM data over 28- and 92-nights in 35 patients was reviewed. There was minimal variability in SDB and no significant difference between durations. For hypothesis 3, 72 patients were followed up at a median of 532 (IQR 386-736) days.Mean event-free survival was 660±344 days (95% CI 535-785 days) in the insignificant SDB group and 854±413 days (95% CI 730-978 days) in the significant SDB group (p=0.25 by log rank test). Conclusions ApneaScanTM, with an optimal cut-off of 30.5 events/hour, is a sensitive means of screening for SDB in patients with HF with a high negative predictive value. Readings above 30.5/hour require further investigation with a sleep study. Night-to-night variability in SDB is minimal and repeat sleep studies should be reserved for those with ‘borderline’ AHI. In this cohort, the presence of SDB was not associated with adverse cardiovascular outcomes. Recruitment is on-going to test this further.Open Acces