Wang Wei, Verin Eric, Sériès Frédéric
Centre Recherche, Hôpital Laval, Institut Universitaire de Cardiologie et de Pneumologie de l'Université Laval, Québec, Canada G1V 4G5.
Clin Sci (Lond). 2006 Nov;111(5):349-55. doi: 10.1042/CS20060038.
MB (mouth breathing) promotes the occurrence of sleep-disordered breathing even in non-apnoeic subjects. Considering that MO (mouth opening) contributes to an increase in UA (upper airway) collapsibility independently of MB, the aim of the present study was to assess the influence of breathing route on UA dynamics in the presence of MO. Bilateral anterior magnetic phrenic nerve stimulation was performed 2 s after expiratory onset in 12 healthy male subjects during wakefulness (age, 50+/-5 years; body mass index, 27.8+/-2.4 kg/m(2)) during MB through a mouthpiece and during exclusive NB (nasal breathing) with the same mouthpiece in place. Twitch-induced V(I) (instantaneous flow), P(ph) and P(es) (pharyngeal and oesophageal pressures respectively) were recorded and the corresponding resistances were measured. A polynomial regression model, V(I)=k(1)P(d)+k(2)P(d)(2), was used to characterize flow-pressure relationship and to determine the P(d) value at which UA collapses. There was no difference in UA dynamic properties between NB and MB when UA collapse occurred above the pharyngeal catheter. For twitches where UA collapse occurred lower in the UA, pharyngeal resistance decreased from NB to MB (2.0+/-0.3 and 1.5+/-0.2 cmH(2)Oxl(-1)xs respectively; P=0.02; values are means+/-S.D.), whereas closing pressure increased (-25.7+/-10.1 and -18.0+/-3.0 cmH(2)O respectively; P=0.04). We conclude that (i) in the presence of MO the dynamic properties of the proximal UA free of phasic activity do not differ between NB and MB, and (ii) MB decreases the upstream resistance and increases collapsibility of the distal UA.
口呼吸（MB）即使在非呼吸暂停受试者中也会促进睡眠呼吸紊乱的发生。鉴于张口（MO）会独立于口呼吸导致上气道（UA）可塌陷性增加，本研究的目的是评估在存在张口的情况下呼吸途径对UA动力学的影响。在12名健康男性受试者清醒时（年龄50±5岁；体重指数27.8±2.4kg/m²），于呼气开始后2秒通过咬嘴进行双侧前膈神经刺激，分别在通过咬嘴进行口呼吸（MB）和使用同一咬嘴进行单纯鼻呼吸（NB）时进行。记录抽搐诱发的瞬时流量（V(I)）、咽部压力（P(ph)）和食管压力（P(es)），并测量相应的阻力。采用多项式回归模型V(I)=k(1)P(d)+k(2)P(d)²来表征流量-压力关系，并确定UA塌陷时的P(d)值。当UA在咽部导管上方塌陷时，NB和MB之间的UA动态特性没有差异。对于UA塌陷发生在UA较低位置的抽搐，咽部阻力从NB到MB降低（分别为2.0±0.3和1.5±0.2cmH₂O·l⁻¹·s；P=0.02；数值为平均值±标准差），而闭合压力增加（分别为-25.7±10.1和-18.0±3.0cmH₂O；P=0.04）。我们得出结论：（i）在存在张口的情况下，无相位活动的近端UA的动态特性在NB和MB之间没有差异；（ii）口呼吸会降低上游阻力并增加远端UA的可塌陷性。
