Verma Manisha, Seto-Poon Margaret, Wheatley John R, Amis Terence C, Kirkness Jason P
Ludwig Engel Centre for Respiratory Research, Westmead Hospital, Westmead, NSW 2145, Australia.
J Physiol. 2006 Aug 1;574(Pt 3):859-66. doi: 10.1113/jphysiol.2005.102129. Epub 2006 May 11.
We have recently demonstrated that the severity of sleep-disordered breathing in obstructive sleep apnoea hypopnoea syndrome (OSAHS) can be reduced by lowering the surface tension (gamma) of the upper airway lining liquid (UAL). Morning xerostomia (related to oral breathing during sleep) is reported by most OSAHS patients. In the present study we examine relationships between breathing route, oral mucosal 'wetness' and the gamma of UAL. We studied eight healthy subjects (age, 25 +/- 5 years [mean +/- S.D.]; body-mass index, 23 +/- 2 kg m(-2)) during a 120 min challenge of both nasal-only breathing (mouth taped) and oral-only breathing (nose clip), each on a separate day (randomized). Both oral mucosal 'wetness' (5 s contact gravimetric absorbent paper strip method) and the gamma ('pull-off' force technique) of 0.2 microl samples of UAL obtained from the posterior pharyngeal wall were measured at 15 min intervals (mouth tape removed and replaced as required). Upper airway mucosal 'wetness' increased during 120 min of nasal breathing from 4.0 +/- 0.4 (mean +/- S.E.M.) to 5.3 +/- 0.3 microl (5 s)(-1) but decreased from 4.5 +/- 0.4 to 0.1 +/- 0.2 microl (5 s)(-1) with oral breathing (both P < 0.001, repeated-measures ANOVA, Tukey's multiple comparison test, post hoc test). Concurrently, the gamma of UAL decreased from 59.3 +/- 2.2 to 51.8 +/- 0.98 mN m(-1) with nasal breathing but increased from 64.4 +/- 2.7 to 77.4 +/- 1.1 mN m(-1) with oral breathing (P < 0.001). For the group and all conditions studied, gamma of UAL values strongly correlated with upper airway mucosal 'wetness' (correlation coefficient, r2 = -0.34, P < 0.001; linear regression). We conclude that oral breathing increases and nasal breathing decreases the gamma of UAL in healthy subjects during wakefulness. We speculate that nasal breathing in OSAHS patients during sleep may promote a low gamma of UAL that may contribute to reducing the severity of sleep-disordered breathing.
我们最近证实，通过降低上气道衬液（UAL）的表面张力（γ），可减轻阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者睡眠呼吸紊乱的严重程度。多数OSAHS患者都有晨起口干（与睡眠时经口呼吸有关）的症状。在本研究中，我们探讨了呼吸途径、口腔黏膜“湿润度”与UAL的γ之间的关系。我们对8名健康受试者（年龄25±5岁[均值±标准差]；体重指数23±2 kg/m²）进行了研究，分别在单独的日子（随机安排）进行120分钟的仅经鼻呼吸（口部粘贴胶布）和仅经口呼吸（鼻夹）挑战。每隔15分钟测量口腔黏膜“湿润度”（5秒接触重量法吸水纸条法）以及从咽后壁获取的0.2微升UAL样本的γ（“剥离”力技术），根据需要移除并更换口部胶布。在120分钟的经鼻呼吸过程中，上气道黏膜“湿润度”从4.0±0.4（均值±标准误）增加至5.3±0.3微升/（5秒），而经口呼吸时则从4.5±0.4降至0.1±0.2微升/（5秒）（均P<0.001，重复测量方差分析、Tukey多重比较检验、事后检验）。同时，经鼻呼吸时UAL的γ从59.3±2.2降至51.8±0.98 mN/m，而经口呼吸时则从64.4±2.7升至77.4±1.1 mN/m（P<0.001）。对于所研究的所有条件下的该组受试者，UAL的γ值与上气道黏膜“湿润度”密切相关（相关系数，r² = -0.34，P<0.001；线性回归）。我们得出结论，在清醒状态下，经口呼吸会使健康受试者UAL的γ增加，而经鼻呼吸会使其降低。我们推测，OSAHS患者睡眠时经鼻呼吸可能会促使UAL的γ降低，这可能有助于减轻睡眠呼吸紊乱的严重程度。
