Childhood OSA is increasingly recognized to be associated with a variety of complications including neurocognitive and cardiovascular diseases. The intermediate link between OSA and end organ damage has been suggested to be inflammation, and both local airway and systemic inflammation have been described in adults with OSA. A non-invasive technique of sputum induction was utilised to show that children with OSA also have airway inflammation, as characterized by a significant increase in neutrophils, and the severity of OSA also correlated significantly with the degree of neutrophilic inflammation (Chapter 7). This finding may lead to research on the use of anti-inflammatory therapeutic agents or antibiotics for the treatment of childhood OSA. Another marker of inflammation, C-reactive protein (CRP) was measured in a cohort of children with OSA before and after treatment (Chapter 8). Children with OSA had higher CRP levels compared to their non-OSA counterparts, and the raised CRP decreased significantly following treatment suggesting that the inflammatory response is potentially reversible. The cardiovascular risk factors of insulin levels and blood pressure (BP) were evaluated and children with OSA had higher serum insulin and greater systolic and diastolic BP compared to healthy controls (Chapters 9 and 10). These findings suggest that children with OSA may be at risk of developing metabolic syndrome and its devastating consequence. (Abstract shortened by UMI.) / The original research studies undertaken were based on nocturnal sleep examinations to explore childhood OSA in two main aspects, namely its assessment, and a better understanding of its complications in children. The gold standard for diagnosing OSA is overnight polysomnography (PSG), which is an expensive investigation that is not routinely available at all public hospitals in Hong Kong. Alternative valid assessment tools for OSA that are more cost-effective are needed. The feasibility of using radiographic techniques to assess severity of OSA was explored, and the size of the upper airway, as reflected by the tonsillar pharyngeal (TP) ratio obtained from lateral neck radiograph, correlated well with the severity of OSA (Chapter 4). A defined TP cutoff could accurately predict moderate-to-severe OSA with high sensitivity and specificity. This method could be used in clinical practice to prioritize patients with suspected OSA for further evaluation. A locally applicable questionnaire scale was examined for its validity and accuracy in diagnosing children with OSA (Chapter 5). The presence of three symptoms (snoring, mouth breathing and nocturnal sweating) was found to have high predictive value in correctly identifying children with the condition. The question of whether a single night PSG study is adequate in diagnosing OSA was examined together with the assessment for the presence of night-to-night variability in PSG and respiratory parameters in childhood sleep (Chapter 6). Forty-four obese children and 43 age and sex-matched healthy controls underwent two consecutive nights PSG examination. Although a first night effect was clearly documented, a single night PSG study would have correctly identified over 80% of children with OSA. This finding has significant resource implications. / Albert Martin Li. / Adviser: Tony Nelson. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3420. / Thesis (M.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves xxxv-lxxx). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English only. / School code: 1307.

Ng, Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves xvi-xlviii). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.i / ABSTRACT / In English --- p.ii / In Chinese --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURE --- p.viii / ABBREVIATIONS / For Units --- p.ix / For Prefixes of the International System of Units --- p.ix / For Terms Commonly Used --- p.X / Chapter CHAPTER 1 --- Overview of Childhood Obstructive Sleep Apnoea Syndrome (OSAS) / Chapter 1.1 --- Prevalence --- p.1 / Chapter 1.2 --- Clinical Features --- p.3 / Chapter 1.3 --- Definitions and Cutoffs --- p.4 / Chapter 1.4 --- Pathophysiology --- p.6 / Chapter 1.5 --- Risk Factors / Chapter 1.5.1 --- Gender --- p.8 / Chapter 1.5.2 --- Obesity --- p.9 / Chapter 1.5.3 --- Adenotonsillar Hypertrophy --- p.10 / Chapter 1.5.4 --- Genetic --- p.11 / Chapter 1.5.5 --- Atopic Diseases --- p.12 / Chapter 1.6 --- Complications / Chapter 1.6.1 --- Neurobehavioural Deficits --- p.13 / Chapter 1.6.2 --- Growth Defects --- p.14 / Chapter 1.6.3 --- Metabolic Disorders --- p.16 / Chapter 1.6.4 --- Systemic inflammation --- p.17 / Chapter 1.6.5 --- Cardiovascular Consequences --- p.19 / Chapter 1.7 --- Diagnosis --- p.20 / Chapter 1.8 --- Treatment / Chapter 1.8.1 --- Surgical Treatment --- p.22 / Chapter 1.8.2 --- Continuous Positive Airway Pressure (CPAP) --- p.24 / Chapter 1.8.3 --- Corticosteroids --- p.24 / Chapter 1.8.4 --- Leukotriene Receptor Antagonist --- p.25 / Chapter 1.8.5 --- Oral Appliances --- p.26 / Chapter 1.8.6 --- Weight Control --- p.27 / Chapter CHAPTER 2 --- OSAS and Cardiovascular Complications in Adults / Chapter 2.1 --- Mechanism / Chapter 2.1.1 --- Acute Cardiovascular Responses --- p.28 / Chapter 2.1.2 --- Chronic Cardiovascular Responses --- p.29 / Chapter 2.2 --- Hypertension / Chapter 2.2.1 --- Epidemiological and Clinical Data --- p.31 / Chapter 2.2.2 --- Characteristics --- p.32 / Chapter 2.2.3 --- Mechanisms --- p.33 / Chapter 2.2.4 --- Treatment --- p.34 / Chapter 2.3 --- Heart Failure --- p.35 / Chapter 2.4 --- Stroke --- p.37 / Chapter 2.5 --- Cardiac Arrhythmias --- p.39 / Chapter 2.6 --- Myocardial Ischemia and Vascular Disease --- p.41 / Chapter 2.7 --- Pulmonary Hypertension --- p.43 / Chapter CHAPTER 3 --- OSAS and cardiovascular complication in children / Chapter 3.1 --- Blood Pressure --- p.45 / Chapter 3.2 --- Ventricular Hypertrophy and Dysfunctions --- p.48 / Chapter 3.3 --- Heart Rate Variability --- p.50 / Chapter 3.4 --- Arterial Tone --- p.51 / Chapter 3.5 --- Endothelial Function --- p.51 / Chapter CHAPTER 4 --- Longitudinal follow-up study of children with OSAS - a cardiovascular perspective / Chapter 4.1 --- Introduction --- p.53 / Chapter 4.2 --- Methods / Chapter 4.2.1 --- Subjects and Study Design --- p.57 / Chapter 4.2.2 --- Polysomnography --- p.59 / Chapter 4.2.3 --- Ambulatory Blood Pressure Measurement --- p.61 / Chapter 4.2.4 --- Statistical Analysis --- p.62 / Chapter 4.3 --- Results / Chapter 4.3.1 --- Subject Characteristics --- p.64 / Chapter 4.3.2 --- Blood Pressure During Wakefulness --- p.71 / Chapter 4.3.3 --- Blood Pressure During Sleep --- p.76 / Chapter 4.3.4 --- Nocturnal Blood Pressure Dipping --- p.83 / Chapter 4.3.5 --- Blood Profile --- p.86 / Chapter 4.4 --- Discussion --- p.87 / Chapter 4.5 --- Conclusion --- p.99 / Reference List --- p.xvi

Au, Chun Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves xxvii-lv). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.i / ABSTRACT / In English --- p.ii / In Chinese --- p.v / LIST OF TABLES --- p.vii / ABBREVIATIONS / For Units --- p.ix / For Prefixes of the international system of units --- p.ix / For Terms commonly used in the report --- p.x / STATEMENT OF WORK DONE --- p.xvi / Chapter CHAPTER 1 --- Overview of Childhood Obstructive Sleep Apnea Syndrome (OSAS) / Chapter 1.1. --- Clinical Features of Childhood OSAS --- p.1 / Chapter 1.2. --- Definition of Childhood OSAS --- p.2 / Chapter 1.3. --- Prevalence of Childhood OSAS --- p.3 / Chapter 1.4. --- Pathophysiology --- p.4 / Chapter 1.5. --- Risk Factors --- p.6 / Chapter 1.6. --- Diagnosis --- p.10 / Chapter 1.7. --- Treatment / Chapter 1.7.1. --- Tonsillectomy and Adenoidectomy (T&A) --- p.12 / Chapter 1.7.2. --- Continuous Positive Airway Pressure (CPAP) --- p.14 / Chapter 1.7.3. --- Corticosteroids --- p.15 / Chapter 1.7.4. --- Leukotriene Receptor Antagonist --- p.16 / Chapter 1.8. --- Complications of Childhood OSAS / Chapter 1.8.1. --- Growth Failure --- p.17 / Chapter 1.8.2. --- Neurocognitive Abnormalities --- p.19 / Chapter 1.8.3. --- Cardiovascular Abnormalities --- p.20 / Chapter CHAPTER 2 --- Cardiovascular Complications of OSAS in Adults (Literature Review) / Chapter 2.1. --- Acute Effects of OSAS on Cardiovascular System --- p.21 / Chapter 2.2. --- Chronic Effects of OSAS on Cardiovascular System --- p.23 / Chapter 2.3. --- Hypertension --- p.24 / Chapter 2.4. --- Heart Failure --- p.28 / Chapter 2.5. --- Pulmonary Hypertension --- p.30 / Chapter 2.6. --- Arrhythmias --- p.31 / Chapter 2.7. --- Cardiac Ischemia and Vascular Disease --- p.33 / Chapter 2.8. --- Stroke --- p.34 / Chapter CHAPTER 3 --- Cardiovascular Complications of Childhood OSAS (Literature Review) / Chapter 3.1. --- Blood Pressure --- p.37 / Chapter 3.2. --- Ventricular Structure and Function --- p.40 / Chapter 3.3. --- Arterial Distensibility --- p.42 / Chapter 3.4. --- Heart Rate Variability --- p.42 / Chapter CHAPTER 4 --- Ambulatory Blood Pressure in Children with OSAS / Chapter 4.1. --- Introduction --- p.44 / Chapter 4.2. --- Methods / Chapter 4.2.1. --- Subjects and Study Design --- p.46 / Chapter 4.2.2. --- Polysomnography (PSG) --- p.47 / Chapter 4.2.3. --- Ambulatory Blood Pressure Measurement (ABPM) --- p.49 / Chapter 4.2.4. --- Statistical Analysis --- p.50 / Chapter 4.3. --- Results / Chapter 4.3.1. --- Subject Characteristics --- p.52 / Chapter 4.3.2. --- Blood Pressure during Wakefulness --- p.55 / Chapter 4.3.3. --- Blood Pressure during Sleep --- p.57 / Chapter 4.4. --- Discussion --- p.62 / Chapter 4.5. --- Conclusion --- p.70 / Chapter CHAPTER 5 --- Cardiac Remodeling and Dysfunction in Children with OSAS / Chapter 5.1. --- Introduction --- p.71 / Chapter 5.2. --- Methods / Chapter 5.2.1. --- Subjects and Study Design --- p.72 / Chapter 5.2.2. --- Polysomnography (PSG) --- p.74 / Chapter 5.2.3. --- Conventional Echocardiography --- p.75 / Chapter 5.2.4. --- Tissue Doppler Imaging --- p.76 / Chapter 5.2.5. --- Statistical Analysis --- p.77 / Chapter 5.3. --- Results / Chapter 5.3.1. --- Study Population --- p.79 / Chapter 5.3.2. --- Polysomnographic Findings --- p.79 / Chapter 5.3.3. --- Echocardiographic Findings / Chapter 5.3.3.1. --- Right Ventricle --- p.81 / Chapter 5.3.3.2. --- Left Ventricle --- p.83 / Chapter 5.3.4. --- Treatment Effect --- p.86 / Chapter 5.4. --- Discussion --- p.90 / Chapter 5.5. --- Conclusion --- p.95 / Chapter CHAPTER 6 --- Conclusion --- p.96 / APPENDIX I Hong Kong Children Sleep Questionnaire (Chinese) --- p.xvii / APPENDIX II Hong Kong Children Sleep Questionnaire (English) --- p.xxii / REFERENCES --- p.xxvii