睡眠醫學二十四之除CPAP以外
最近再次與偉民(假名)茶聚時，自不然問候他睡眠窒息症(Obstructive Sleep Apnea,
OSA)的情況，他卻滿腹牢騷地投訴連續正氣壓機(CPAP)的各種不是。雖然CPAP能改善他睡眠窒息症的病徵，但卻是個治標不治本的方案，要”成世人”晚晚都用CPAP超過四小時! 大多數病人真的很難有如此恆心。我也明白偉民的感受。大部份研究亦發現病人對CPAP 的遵從性[Adherence] 不高，新型的面罩及CPAP 機也無助改善這個現象[1]。身形龐大的偉民好奇地問我:「減肥是否可根治睡眠窒息症?」從各種關於減肥的研究[包括改變飲食習慣及減肥手術] 結果來說，減肥的確有助改善睡眠窒息症的病情，但卻甚少能根治睡眠窒息症 [2,3]，而且不能及不應在極短時間內大幅度減肥，否則更加危害健康。
而特制的牙膠[ ORAL APPLIANCE,OA]
有助將下顎[Mandible]及或脷拉前，從而防止病人在睡眠時上氣道崩塌[upper airway collapse]。而OA治療睡眠窒息症的效能在乎儀器能將下顎拉前多少[4-6] ，但OA亦有一定的副作用: 分泌過多口水、口腔或牙肉不適、牙關及其肌肉拉緊[7]，雖然這些副作用大多是輕微和短暫，但已令某些人放棄OA的治療[8]，長期使用OA亦會令病人面相有所改變[9]。醫生一般只會對患上輕度睡眠窒息症的病人使用OA， OA醫治睡眠窒息症的效能確實較CPAP次優，病人使用OA後可能每小時仍有15至20次的窒息[10] 。但由於病人對CPAP的遵從率[adherence]
偏低，最後OA 的整體的治療效果亦能達至與CPAP相若[11-14]，而且同樣能降低血壓[15-16] 。當然如果病人增肥了，OA的醫療效率自然會下降[17]。
近年本港相當流行一種口腔運動[oropharyngeal
exercise/myofunctional therapy]，它是源於語言治療[consisting of
isometric and isotonic exercises involving the tongue , soft palate and lateral
pharyngeal wall][18]，初步研究發現此等口腔運動對睡眠窒息症有一定裨益[19-20]，但病人要有持之以恆，勤於練習才能發揮功效，情況與使用CPAP治療睡眠窒息症相似-靠恆心!
這時我從口袋中取出兩片特殊鼻貼名為Nasal EPAP，這個小玩意是分別貼在病人兩個鼻孔，當病人吸氣時，外邊的空氣在沒有任何阻擋的情況下被吸入鼻孔內；呼氣時活門卻關上，鼻孔內空氣只能從兩個小孔呼出，氣管壓力因而增加，將受堵塞的呼吸道打開打開。[These valves operate
by utilizing the patient’s own breathing to create a positive end-expiratory
pressure with minimal inspiratory resistance. This high end-expiratory pressure
leads to upper airway dilation with subsequent tracheal traction and increased
lung volumes during exhalation, thereby making the upper airway more resistant
to narrowing/closure during ensuing inspiration] [21-22] 。本港威爾斯醫院亦發表過關於這個儀器的小型研究[23]，發現nasal EPAP 對睡眠窒息症有一定的舒緩作用，若病人不考慮CPAP的話，nasal EPAP 是其中一種另類選擇。較大型的醫學回顧[systemic review] 亦發現病人使用nasal EPAP 後可減少一半窒息次數[24]，奈何暫時不知 nasal EPAP對那類病人最有效[25]。由於病人要每天更換 Nasal EPAP ，所以長期使用nasal EPAP的費用實在不輕，因而亦會影響它的流行性。
美國藥物管理局[USA Food
and Drug Administration, FDA]最近批淮了一個類似心臟起搏器的儀器[UPPER
AIRWAY STIMULATION, UAS]，作醫治睡眠窒息症之用，其原理是當病人入睡了，UAS會刺激病人特定的神經線[HYPOGLOSSAL nerve] 令病人的脷及軟齶[soft plate] 移動，從而擴闊了氣道
[retrolingular and retropalatal airways][26] 。
總括來說，在各種另類治療睡眠窒息症方案之中，唯有牙膠 [Oral Appliance] 擁有豐富的醫學實證，但CPAP 仍是醫治阻塞性睡眠窒息症的第一線有效策略。
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