published_or_final_version / Surgery / Master / Master of Medical Sciences

　　　Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder and is associated with a range of adverse physical, social and psychological outcomes that affect quality of life (QoL). Two systematic reviews of the literature (part of this thesis work) found there is conflicting evidence of how different mandibular advancement device (MAD) designs features may affect clinical and subjective OSA outcomes in certain patients. Therefore, a randomized cross-over trial was conducted. Firstly, the correlation between clinical OSA indicators and QOL was explored among patients referred for OSA treatment using MADs. In addition, associations of OSA risk factors, dental status and demographic variables with clinical OSA indicators and QoL indices were determined. Secondly, the efficacy of two different MADs in the treatment of adult OSA patients was assessed and compared. Thirdly, the efficacy of the two MADs in the treatment of adult OSA patients from the subjective perspective of their bed partners was determined. 　　　A consecutive sample of 45 adult OSA patients referred from Queen Mary Hospital Sleep Centre to the Prince Philip Dental Hospital for oral appliance therapy was recruited and treated with a monobloc MAD and a twinblock MADs for a period of 3 months per MAD (cross-over randomised trial). Changes in clinical OSA outcomes were assessed by polysomnography (PSG) and changes in subjective outcomes by the disease-specific Sleep Apnoea Quality of Life Index (SAQLI) questionnaire, the Functional Outcome of Sleep Questionnaire (FOSQ) and Epworth Sleepiness Scale (ESS). Patient compliance, side-effects and MAD preference, as well as MAD treatment impact on the patients’ bed partner was also assessed. At baseline, some clinical OSA indicators, subjective QoL and certain OSA risk factors were significantly correlated (p<0.05). There were significant variations in clinical OSA indicators and subjective QoL indices with respect to certain risk factors (p<0.05), demographic variables (p<0.05) and dental status (p<0.01). 　　　There was a significant difference in favour of the monobloc MAD in terms of improving the apnoea-hypopnoea index (AHI) (p<0.05) and oxygen desaturation index (ODI) (p<0.01). Significantly more patients achieved clinical treatment success with the monobloc compared to the twinblock (p<0.05). Both MADs were efficacious in improving patients’ SAQLI score (p<0.01), FOSQ score (p<0.01) and ESS score (p<0.01). Significantly more patients achieved QoL treatment success with the monobloc (p<0.05) compared to the twinblock. More patients were ‘very satisfied’ with the monobloc treatment (p<0.05) and 63% preferred it to the twinblock. 　　　 No significant difference was found between patients’ and bed partners perceptions of symptom improvement post treatment, however, the monobloc resulted in a significant reduction in bed partners’ daytime sleepiness (p<0.01) and allowed significantly more co-sleeping at night (p<0.05). 　　　 　　　This study concluded that the monobloc is superior in improving subjective QoL and clinical OSA indicators. The monobloc was the preferred MAD and patients were more satisfied with it; bed partners rated this MAD as superior in improving their own daytime sleepiness and co-sleeping. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Poor adherence to continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnoea (OSA) limits its therapeutic effectiveness and has a major impact on clinical outcomes. Effective education programme is important to enhance CPAP use. However, existing education programmes are either manpower or resource demanding and may not be feasible in clinical practice. Moreover, the Self-Efficacy Measure for Sleep Apnoea (SEMSA) has been widely adopted for assessing adherence-related cognitions on CPAP therapy in OSA patients, but it was not available for Chinese. The aims of this thesis are: (i) to perform linguistic and psychometric evaluation of a Chinese version of SEMSA (SEMSA-C); (ii) to examine the efficacy of brief motivational enhancement education programme in addition to standard care versus standard care only on improving adherence to CPAP treatment in patients with OSA. The SEMSA-C was obtained after the standard forward-backward translation process. A randomised controlled trial was then conducted on newly diagnosed OSA patients. Patients in the control group received standard care (SC) comprising advice on the importance of CPAP therapy and its care while those in the intervention group received SC plus motivational enhancement education programme (ME). ME focused to enhance subjects’ knowledge, motivation and self-efficacy to use CPAP, comprising one 45-minute session on the day after CPAP titration and one 10-minute telephone follow-up shortly after commencing CPAP treatment. Epworth Sleepiness Scale (ESS), SEMSA-C, and quality of life were assessed. CPAP usage data were downloaded at the completion of this 3-month study. The primary outcome was the CPAP adherence. Furthermore, 21 patients were randomly sampled at baseline and completed the SEMSA-C at one week. 100 patients (Men : Women, 84 : 16) with OSA indicated for CPAP treatment were recruited, with an average age of 52±10 years, and apnoea hypopnoea index (AHI) of 36.2±22 events/hour. Factor analysis of SEMSA-C identified three factors: risk perception, outcome expectancies and treatment self-efficacy. Their corresponding internal consistency was high with Cronbach’s alpha >0.88, which were larger than all correlations between subscales (Range: 0.14 to 0.58). The correlations between items and their hypothesized subscale (Range: 0.58 to 0.85) were generally higher than the correlations between items and their competing subscales (Range: -0.10 to 0.58). One-week test-retest intra-class correlation ranged from 0.70 to 0.82. CPAP adherence was associated with outcome expectancies and treatment self-efficacy at 3-month assessment. Furthermore, SEMSA-C demonstrated an improvement in self-efficacy (standardised response mean = 0.33, p = .044) but no significant changes were observed in the other two factors, after CPAP use. The 100 patients were followed for 3 months. The interventional effects maintained during the 3-month study period. There were a better CPAP use [higher daily CPAP usage of 2 hours/day (Cohen d = 1.33, p < .001), four-fold the number of subjects using CPAP for ≥ 70% of days with ≥ 4 hours per day (p < 0.001)], and greater improvements in ESS by 2.2 (p = 0.001) and treatment self-efficacy by 0.2 (p = 0.012) in the intervention group, relative to the control group. The traditional Chinese SEMSA-C possesses satisfactory psychometric properties. It is a reliable and responsive instrument to measure perceived risks, outcome expectancies and treatment self-efficacy in Chinese patients with OSA. Moreover, the newly developed brief motivational enhancement education programme in addition to standard care is effective in improving adherence to CPAP treatment, treatment self-efficacy and daytime sleepiness. / published_or_final_version / Nursing Studies / Doctoral / Doctor of Nursing

Obstructive Sleep Apnea (OSA) is a common respiratory disorder during sleep. Apnea is cessation of airflow to the lungs, which lasts for at least 10 seconds accompanied by more than 4% drop of the blood's Oxygen saturation. Polysomnography during the entire night is the Gold Standard diagnostic method of OSA. It's high cost and inconvenience for patients persuaded researchers to seek alternative OSA detection methods. This thesis proposes a technique for assessment of OSA during wakefulness. We recorded tracheal breath sounds of 17 non-apneic individuals and 35 people with various degrees of OSA severity in supine and upright positions during nose and mouth breathing at medium flow rate. We calculated the power spectrum, Kurtosis, and Katz fractal dimensions of the recorded signals. Then, we reduced the number of characteristic features to two. We classified the participant into severe OSA and non-OSA groups as well as non-OSA or mild vs. moderate and severe OSA groups. The results showed more than 91 and 83% accuracy; for the two types of classification. Once veri ed on a larger population, the proposed method may be used as a simple and non-invasive screening tool for assessment of OSA during wakefulness.

Obstructive Sleep Apnea (OSA) is a common respiratory disorder during sleep. Apnea is cessation of airflow to the lungs, which lasts for at least 10 seconds accompanied by more than 4% drop of the blood's Oxygen saturation. Polysomnography during the entire night is the Gold Standard diagnostic method of OSA. It's high cost and inconvenience for patients persuaded researchers to seek alternative OSA detection methods. This thesis proposes a technique for assessment of OSA during wakefulness. We recorded tracheal breath sounds of 17 non-apneic individuals and 35 people with various degrees of OSA severity in supine and upright positions during nose and mouth breathing at medium flow rate. We calculated the power spectrum, Kurtosis, and Katz fractal dimensions of the recorded signals. Then, we reduced the number of characteristic features to two. We classified the participant into severe OSA and non-OSA groups as well as non-OSA or mild vs. moderate and severe OSA groups. The results showed more than 91 and 83% accuracy; for the two types of classification. Once veri ed on a larger population, the proposed method may be used as a simple and non-invasive screening tool for assessment of OSA during wakefulness.

Thesis (M.Nurs.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 112-122)

Thesis (M.S.) -- Central Connecticut State University, 2008. / Thesis advisor: Ruth Rollin. "... in partial fulfillment of the requirements for the degree of Master of Science in Biology." Includes bibliographical references (leaves 39-41). Also available via the World Wide Web.

Thesis (M. Orth.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 125-144, 225-227).

Thesis (M.Orth.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 125-144, 225-227). Also available in print.

Background: Obstructive sleep apnea (OSA) is a sleep disorder characterized by episodes of cessation of breathing (apnea) during sleep. Unfortunately, a significant number of surgical patients are unaware they are afflicted with this disorder increasing the risks of postoperative complications. The lingering effect of general anesthesia causes an increase in frequency of airway collapse, leading to longer periods of apnea. This increasingly common sleep disorder is concerning for many anesthesia providers. Purpose: The purpose of this study was to evaluate the anesthesia provider's knowledge and postoperative management of patients with suspected or diagnosed OSA. Setting: The study setting was a local urban hospital Mountain Vista Medical Center (MVMC) in Gilbert, AZ. The study included (N=7) participants, who were predominantly male (85%) and a majority of the participants were Master’s prepared (85%) anesthesia providers. Method: An online survey was disseminated to participants via email. The survey included questions regarding the anesthesia provider's knowledge and postoperative practice habits of patients with suspected or diagnosed OSA at MVMC. Results: The response rate was (24%). All the respondents acknowledged that OSA was a risk factor for postoperative complications. Over half of the respondents (85%) reported encountering postoperative complications such as desaturation and apnea in their patients with OSA. The main complication that was encountered was postoperative apnea (50%), followed by decreased in saturations (33.33%), and one respondent (16.67%) encountered re-intubation during the postoperative period. However, the most important finding of the study is that over half of the providers did not routinely include continued positive airway pressure (CPAP)/noninvasive positive pressure ventilation (NIPPV) in their postoperative management of patients with suspected or known OSA due to the time needed to initiate the therapy. Conclusion: The study illustrates that a majority of anesthesia providers at MVMC agreed OSA is a significant risk factor for postoperative complications, but time constraints limited the implementation of noninvasive ventilation (NIV) therapies. Recommended strategies would be to establish a task force to examine this barrier to therapy and develop plans to address it.