Roberts J L, Reed W R, Mathew O P, Menon A A, Thach B T
J Appl Physiol (1985). 1985 Jan;58(1):290-9. doi: 10.1152/jappl.1985.58.1.290.
A current hypothesis for obstructive sleep apnea states that 1) negative airway pressure during inspiration can collapse the pharyngeal airway, and 2) neural control of pharyngeal airway-dilating muscles is important in preventing this collapse. To test this hypothesis we performed nasal mask occlusions to increase negative pharyngeal airway pressures during inspiration in eight normal and five micrognathic infants. Both groups developed midinspiratory pharyngeal obstruction, but obstruction was more frequent in micrognathic infants and varied in some infants with sleep state. The airway usually reopened with the subsequent expiration. The occasional failure to reopen was presumably due to pharyngeal wall adhesion. If airway obstruction occurred in sequential breaths during multiple-breath nasal mask occlusions in normal infants, there was a breath-by-breath change in the airway pressure associated with airway closure (airway closing pressure); the airway closing pressure became progressively more negative. Micrognathic infants showed less ability to improve the airway closing pressure, but this ability increased with age. These findings suggest that nasal mask occlusion can test the competence of the neuromuscular mechanisms that maintain pharyngeal airway patency in infants. Micrognathic infants had spontaneous midinspiratory pharyngeal airway obstructions during snoring. Their episodes of obstructive apnea began with midinspiratory pharyngeal obstruction similar to that seen during snoring and nasal mask occlusions. These findings imply a similar pathophysiology for snoring, spontaneous airway obstruction, and obstruction during snoring.
1）吸气时气道内的负压可使咽部气道塌陷；2）咽部气道扩张肌的神经控制对于防止这种塌陷很重要。为了验证这一假说，我们对8名正常婴儿和5名小颌畸形婴儿进行了鼻罩阻塞，以在吸气时增加咽部气道的负压。两组婴儿均出现吸气中期咽部梗阻，但小颌畸形婴儿中梗阻更为常见，且在一些婴儿中随睡眠状态而变化。气道通常在随后的呼气时重新开放。偶尔未能重新开放可能是由于咽壁粘连。如果在正常婴儿多次呼吸鼻罩阻塞过程中连续呼吸时发生气道梗阻，则与气道关闭相关的气道压力会逐次变化（气道关闭压）；气道关闭压会逐渐变得更负。小颌畸形婴儿改善气道关闭压的能力较弱，但这种能力会随着年龄增长而增强。这些发现表明，鼻罩阻塞可测试维持婴儿咽部气道通畅的神经肌肉机制的功能。小颌畸形婴儿在打鼾时会出现自发性吸气中期咽部气道梗阻。他们的阻塞性呼吸暂停发作始于吸气中期咽部梗阻，类似于打鼾和鼻罩阻塞时所见的情况。这些发现意味着打鼾、自发性气道梗阻和打鼾时的梗阻具有相似的病理生理学机制。
