一瞬間己是三十五年的友情歲月

睡眠醫學二十九之兒童睡眠窒息症

今晚出席了振華小姨Vivian囝囝的百日宴，Vivian除了多謝我出席宴會外，因為她在懷孕期間患上了睡眠窒息症，而睡眠窒息症有可能會遺傳，因此她順道與我傾談了許多關於兒童睡眠窒息症的問題。

大概有一成兩歳至八歲的小朋友會習慣打鼻鼾，而兒童睡眠窒息症的發病率(Prevalence)約是2至5%(1,2)。不同民族有不同的發病率，亞洲的小朋友亦類似亞洲成人-有較高的發病率。其實睡眠窒息症最早可以在嬰兒時代就發病，尤以早產嬰為甚，大多數病人是在兩歳至十歲期間發病。睡眠窒息症的男女小朋友發病比例是1:1，但進入青春期後，男性患者的比例明顯增加。

肥胖，扁桃線(Tonsil)及腺樣(adenoid)肥大是兒童睡眠窒息症的主因(3)，但各種面部、口腔及喉部的異常結構同樣可以引發兒童睡眠窒息症的。甲狀腺功能減退症(hypothyroidism)及唐氏綜合症(Down syndrome)會令病人脷的體積過大，造成上呼吸道不暢通。其他與兒童睡眠窒息症的疾病多不勝數:chronic nasal obstruction, neuromuscular diseases; certain storage diseases; marfarn syndrome; achondroplasia; chiari malformation, cerebral palsy, laryngomalacia…。

兒童睡眠窒息症的病徵除了典型的日間嗜睡外、還有發噩夢、夜間遺尿、行為問題，甚至過度活躍等。若延醫可引致小朋友成長不良(failure to thrive)(4)、高血壓(5)、肺源性心臟病(cor pumonale)、胸腔發展異常(pectus excavatum)。更嚴重的可能影響兒童腦部發育及其功能(dysfunction in the prefrontal areas of the brain. Executive dysfunction interferes with cognitive abilities and learning)(6)。雖然診斷兒童睡眠窒息症的黃金標準同是睡眠測試(polysomnography)，但箇中定議及細節卻與成人的完全不同!

處理方案大致有三大類:

第一

動手術(Adenotonsillectomy)切除肥大的扁桃線(Tonsil)及腺樣(adenoid)(7,8)，適用於扁桃線及腺樣過大、有病徵強烈及Apnoea and Hypopnea Index[AHI> 1] 的病人，但手術後睡眠窒息症可以殘存(9)或覆發的。

第二

若病人不宜或不願動手術，可選擇使用連續正氣壓機(continuous positive  airway pressure, CPAP)。手術後睡眠窒息症殘存(Residual OSA)者亦可使用CPAP治療其睡眠窒息症(10-13)。

第三

輕度睡眠窒息症病人可選擇觀望態度，但六個月內必須再小心評估病情(14)。

所有兒童睡眠窒息症的病人都應遠離過敏源(environmental allergen)及剌激源(irritant)，過肥兒童患者應減肥(15,16)，個別病人夜間亦有可能需要使用氧氣(17,18)，最後不能不提城中熱話- Myofunctional therapy (a form of physical therapy consisting of exercise designed to strengthen the tongue and orofacial muscles, with a goal of repositioning muscles to the appropriate position)(19-21)。經治療後，多數小朋友都能回復正常成長，他們的腦功能及行為都會有所改善(22-24)。美國醫學界對兒童睡眠窒息症有非常詳盡的指引(25)。

最後我忍不住安慰Vivian，現在就擔心囝囝將來會否出現睡眠窒息症，實在過慮了，不如擔心能否入讀心儀的幼稚園更實際吧，明天就去排定隊!

參考文獻

1. Increased behavioral morbidity in school-aged children with sleep-disordered breathing. Pediatrics 2004; 114:1640.
2. American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd ed, American Academy of Sleep Medicine, Darien, IL 2014.

3.  The prevalence, anatomical correlates and treatment of sleep-disordered breathing in obese children and adolescents. Sleep Med Rev. 2008 Oct. 12(5):339-46. 

4.  Determinants of growth in children with the obstructive sleep apnea syndrome. J Pediatr. 1994 Oct. 125(4):556-62.

5.  Blood pressure associated with sleep-disordered breathing in a population sample of children. Hypertension. 2008 Nov. 52(5):841-6. 

6.  Obstructive sleep apnea and the prefrontal cortex: towards a comprehensive model linking nocturnal upper airway obstruction to daytime cognitive and behavioral deficits. J Sleep Res. 2002 Mar. 11(1):1-16.

7.  Adenotonsillectomy and obstructive sleep apnea in children: a prospective survey. Otolaryngol Head Neck Surg. 2007 Feb. 136(2):169-75.

8. Diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics 2012; 130:576.

9.   Persistence of obstructive sleep apnea syndrome in children after adenotonsillectomy. J Pediatr. 2006 Dec. 149(6):803-8. 

10. Use of nasal continuous positive airway pressure as treatment of childhood obstructive sleep apnea. J Pediatr 1995; 127:88.
11. Obstructive sleep apnea: the use of nasal CPAP in 80 children. Am J Respir Crit Care Med 1995; 152:780.
12. Home nasal continuous positive airway pressure in infants with sleep-disordered breathing. J Pediatr 1995; 127:905.

13.The pediatric use of bilevel positive airway pressure therapy for obstructive sleep apnea syndrome: a retrospective review with analysis of respiratory parameters. Clin Pediatr (Phila) 2002; 41:163.

14.A randomized trial of adenotonsillectomy for childhood sleep apnea. N Engl J Med 2013; 368:2366

15. The effect of weight loss on sleep-disordered breathing in obese teenagers. Obesity (Silver Spring) 2009; 17:1178.

16.Obstructive sleep apnea in extremely overweight adolescents undergoing bariatric surgery. Obes Res 2005; 13:1175.

17. Supplemental oxygen during sleep in children with sleep-disordered breathing. Am J Respir Crit Care Med 1995; 152:1297.

18.Effects of overnight supplemental oxygen in obstructive sleep apnea in children. Am J Respir Crit Care Med 1996; 153:51.

19. Can myofunctional therapy increase tongue tone and reduce symptoms in children with sleep-disordered breathing? Sleep Breath 2017; 21:1025.
20. Oropharyngeal exercises to reduce symptoms of OSA after AT. Sleep Breath 2015; 19:281.

21.Critical role of myofascial reeducation in pediatric sleep-disordered breathing. Sleep Med 2013; 14:518.

22.Effects of positive airway pressure therapy on neurobehavioral outcomes in children with obstructive sleep apnea. Am J Respir Crit Care Med. 2012 May 1. 185(9):998-1003. .

23.Prognosis for Spontaneous Resolution of Obstructive Sleep Apnea in Children. Chest. 2015 Mar 26.

24.Cognitive Effects of Adenotonsillectomy for Obstructive Sleep Apnea. Pediatrics. 2016 Aug. 138 (2)

25.Diagnosis and Management of Childhood Obstructive Sleep Apnea Syndrome. Pediatrics 2012;130:e714–e755

睡眠醫學二十八之阻塞性睡眠窒息症的顯型

我年青的時候很喜歡到書局打書釘，今天突然心血來潮要再扮” 偽”文青。想不到在書局的大眾心理學角落竟然遇到振華，他洋洋得意捧著一本關於「九型人格」的書。他興奮地分享從這本書學會將下屬分成九種類別，從而亦學會如何駕馭不同型格的下屬。但振華忽然問我能否同樣將阻塞性睡眠窒息症(OSA)分門別類，如此一來，醫治睡眠窒息症不就簡單直接得多了嗎?

雖然近年醫學界對OSA的認識增添了不少，但卻沒有制定什麼普世認同的分類。有個別學者把阻塞性睡眠窒息症分成多種顯型 (phenotypes is defined as an observable expression of an individual’s characteristics that result from the interaction between the individual’s genes (genotype)and the environment, without any implication of a mechanism) 。一如其名，顯型是指病人所顯露出來的表徵，而表徵是由遺傳因子和環境因素交錯而成的。

顯型的種類

年齡層

隨著病人年齡的增長，阻塞性睡眠窒息症愈見普遍，高峰期見於65歲，此後發病率大致平穩。病理是多樣化的(Reduced airway caliber due to preferential deposition of fat around the pharynx makes the aging population anatomically susceptible to OSA (1) Overnight rostral shift of fluids to the neck(2) higher surface tension of the upper airway(3) and decreases in lung volume tethering effect(4) also predispose the elderly population to OSA)。而老齡的OSA病人有別於年青的OSA病人(5):日間嗜睡較輕微；細的肺容量引起圈養後果(tethering contributes to airway collapsibility)；夜間咀唇液體移位(overnight rostral shift of fluid) 較普遍。

更年期

更年期後的婦女患上睡眠窒息症的機會大增(6)，有別於年青婦女患者，她們在Non Rapid Eye Movement [NREM] Sleep 時病情特別嚴重(7)，賀爾蒙補允藥有助減少更年期後的婦女患上OSA的機會(8) 。

種族

亞洲OSA患者較多有顱面骨架異常(Craniofacial skeletal restriction)，而美國非洲裔(African Americans)患者則多因肥胖引起發病，另外(Caucasians) 高加索人種患者同時因顱面骨架異常及肥胖引起發病(9)。所以有不少亞洲OSA患者並不如外國患者般肥胖(10,11) 。

睡眠階段

有個別患者的睡眠窒息主要(predominant)或單單(isolated)發生在Rapid Eye Movement , REM Sleep，約10至36% OSA病人屬這類別(12)。患者多為年長婦女而且她們的病情亦較嚴重(13,14)，這類的睡眠窒息症(REM-related OSA) 特別與高血壓有關(15)。

睡姿

與平臥有關(supine position -related) 的OSA 是相當常見的，其流行率(prevalence) 為20至60%(16)。病理主因乃上呼吸道結構及功能異常( It may be attributable to unfavorable upper airway anatomy, reduced lung volume, and inability of airway dilator muscles to compensate for the airway collapse in the supine position.)。患者多為年青男士，亦非肥胖，可是他們卻出現較嚴重的日間嗜睡(7)。治理這類型病人可考慮側睡(17)、鈄睡(18)。如果這屬病人不想使用連CONTINUOUS POSITIVE AIRWAY PRESSURE THERAPY[CPAP]/持續正壓呼吸機，亦可試用 Mandibular Advancement Devices (MAD)下頜前移矯治器。

上呼吸道狹窄症候群 (Upper Airway Resistance Syndrome)

病人由於上呼吸道狹窄，因而在睡眠中呼吸遇到阻力，最終引致睡夢中覺醒(Respiratory Effort Related Arousal) (19)，但病變機理又未符合睡眠窒息(Apnoea)或低通氣(Hypopnea) 的定義。典型患者是非肥胖年青人士，及有多種顱面骨架異常(Craniofacial abnormalities include low soft palate, long uvula, increased overbites, and a high and narrow hard palate)。

我輕輕拍了振華的膊頭，其實任何疾病的病人都不可能用幾種顯型就可慨括的! 唯一較實際的分類: 老闆(振華)及打工仔(小弟)。

參考文獻:

1.  Aging influences on pharyngeal anatomy and physiology: the predisposition to pharyngeal collapse. Am J Med. 2006;119:72.e9–e14.

2.  Relationship between overnight rostral fluid shift and obstructive sleep apnea in nonobese men. Am J Respir Crit Care Med. 2009;179:241–246.

3.  Relationship between surface tension of upper airway lining liquid and upper airway collapsibility during sleep inobstructive sleep apnea hypopnea syndrome. J Appl Physiol (1985). 2003;95:1761–1766

4.  Effect of increased lung volume on sleep disordered breathing in patients with sleep apnoea. Thorax. 2006;61:435–439.

5.  Obstructive sleep apnea in older adults is a distinctly different physiological phenotype. Sleep. 2014;37:1227–1236

6.  Menopausal status and sleep-disordered breathing in the Wisconsin Sleep Cohort Study. Am J Respir Crit Care Med. 2003;167:1181–1185.

7.  Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis. Respirology 2012;17:99–107.

8.  Prevalence of sleepdisordered breathing in women: effects of gender. Am J Respir Crit Care Med. 2001;163:608–613.

9.  Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: impact of ethnicity. Respirology 2012;17:213–222.

10.A community study of sleep-disordered breathing in middle-aged Chinese women in Hong Kong: prevalence and gender differences. Chest. 2004;125:127–134.

11.Excess weight and sleep-disordered breathing. J Appl Physiol (1985). 2005;99:1592–1599

12.Prevalence, clinical features, and CPAP adherence in REM-related sleep-disordered breathing: a cross-sectional analysis of a large clinical population. Sleep Breath. 2012;16:519–526.

13.Gender differences in the polysomnographic features of obstructive sleep apnea. Am J Respir Crit Care Med. 2000;161:1465–1472

14.Gender differences in obstructive sleep apnea and treatment implications. Sleep Med Rev. 2008;12:481–496.

15.Obstructive sleep apnea during REM sleep and hypertension results of the Wisconsin Sleep Cohort. Am J Respir Crit Care Med. 2014;190:1158–67

16.Prevalence and clinical significance of supine-dependent obstructive sleep apnea in patients using oral appliance therapy. J Clin Sleep Med. 2014;10:959–964.

17.Positional treatment vs continuous positive airway pressure in patients with positional obstructive sleep apnea syndrome. Chest. 1999;115:771–781.

18.Effects of sleep posture on upper airway stability in patients with obstructive sleep apnea. Am J Respir Crit Care Med. 1997;155:199–204.

19.The upper airway resistance syndrome. Chest. 1999;115:1127–1139.

師公葉準師傅大壽2018

睡眠醫學二十七之誰有高風險?

閒來與振華(假名)去歡樂時光(Happy hour)輕鬆一下，忽然他想起我們的老朋友最近突然辭世，不敢悲從中來，他長嘆一聲:「若果人類可以預測某種疾病的來臨，那麼我們就可以避過一劫。」我亦表贊同: 「振華你可想起上一次要做膽石手術? 並不是每個睡眠窒息的病人都這麼幸運，能在手術前已被診斷出來! 否則在沒有充足準備下做手術，手術前後的風險可能會大增呢!」振華自然追問醫生在手術前有什麼方法可以篩查出那位病人患有睡眠窒息症。其實麻醉科醫生可使用以下幾種問卷調查-Berlin questionnaire, STOP-BANG, SACS or ASA checklist，如果發現病人屬高危一族，那最好還是替病人先進行睡眠測試，但大家要明白這些問卷並不能夠在手術前找出所有睡眠窒息症病人的(1)。

在日常臨床診斷中，醫生主觀的感覺或印象往往不能正確診斷出睡眠窒息症(2)，因此醫學界嘗試找出各種更客觀的方案，從而幫助醫護人員篩查出高風險病人。BERLINE QESTIONNAIRE 能成功找出86%的睡眠窒息病人(e.g AHI> 5), 有77% SPECIFICITY [特異性], a positive likelihood ratio of 3.79(3)。而STOP-BANG questionnaire是另一個有深厚醫學實據的問卷調查(4,5,6)，當問卷總分是3分或以上就能篩查出93%中度睡眠窒息症(AHI>15)及100%的嚴重睡眠窒息症(AHI>30)病人，若果總分達7或8分，填卷人士就有60%機會患上嚴重睡眠窒息症了!

振華忍不住打斷了我的講話，問有更簡單的方法嗎? 大家自然想起單單量度頸圍有用嗎? 雖然不同研究對這個方法會有不同結論，但一般都同意頸圍越粗風險就越大(7-10)，更有學者發現用頸圍與高度的比例( neck circumference –height ratio) 會更有用(11)。很久之前已有學者使用Mallampati score ( grades visibility of the posterior pharynx when the patient opens his mouth and stick out his tongue)來評估風險(9)。肥胖自然是另一個研究焦點(12-14)，同樣病人越肥胖就有越高風險患上睡眠窒息症。

 當然亦有學者使用高科技(craniofacial photographic analysis) 從頭部結構來預測病人患上睡眠窒息症的風險(15)。更有研究特別針對心臟病患者患上睡眠窒息症的風險(16,17)。但可惜至今沒有單一預測模式或方案是明顯優勝於他人(18)，值得醫學界一致推崇的。

這時有點醉意的振華冷不防說了一句:「人生根本就不能預測的!」對!不過我就能預測今晚我要送佢返屋企。

參考文獻

1.  Pre-operative screening for obstructive sleep apnoea. Eur Respir Rev 2017;26:160012

2.  Predictive value of clinical features in diagnosing obstructive sleep apnea. Sleep 1993;16(2):118-122

3.  Using Berlin questionnaire to identify patients at risk for the sleep apnoea syndrome. Ann Intern Med 1999;131:485-491.

4.  STOP-BANG questionnaire in obstructive apnea syndrome: a severity predictor. Eur Respir J 2015 46:PA2343

5.  STOP-BANG questionnaire. A practical approach to screen for obstructive sleep apnea. Chest 2016;149(3):631-638

6.  Predicting sleep disordered breathing in outpatients with suspected OSA. BMJ Open 2014;4:e004519

7.  Predictors of sleep disordered breathing in community dwelling adults; the sleep heart health study. Arch Intern Med 2002;162(8):893-900

8.  The occurrence of sleep disordered breathing among middle aged adults. N Engl J Med 1993;328(17):1230-1235

9.  A stepped approach for prediction of obstructive sleep apnea in overtly asymptomatic obese subjects: a hospital based study Sleep Med 2004;5(5):351-357

10.Predictors for presence and severity of obstructive sleep apnea in snoring patients: significance of neck circumference. J Sleep Med 2015;12(2)34-38

11.Neck circumference –height ratio as a predictor of sleep related breathing disorder in children and adults. J Clin sleep Med 2016;12(3):311-7

12.Predicting sleep apnea and excessive day sleepiness in the severely obese .Chest 2003; 123(4):1134-1141

13.Usefulness of truncal obesity indices as predictive factors for obstructive sleep apnea syndrome. Obesity 2008;16:113-8

14.Obesity stratification as a predictor for sleep apnea syndrome. Sleep Medicine 2013;Vol 14, Suppl 1 Pe207

15.Prediction of obstructive sleep apnea with craniofacial photographic analysis. Sleep 2009;3291):46-52

16.Prevalence and predictors of sleep apnea in patients with stable coronary artery disease: a cross sectional study. Therapeutics and clinical risk management 2017;13:1031-1042

17.Prevalence and predictors of sleep disordered breathing in patients with stable chronic heart failure. JACC: Heart Failure 2016.Vol 4,No2

18.Systematic review and meta-analysis of the literature regarding the diagnosis of sleep apnea. Sleep 2000;23:519-532