RESPIRATORY CONTROL OF THE ALAE NASI IN PRETERM INFANTS

鼻翼(Alae nasi，AN)被认为是上肢的呼吸肌 能够改变鼻腔阻力并改变通向鼻腔的气流的呼吸道 肺部。新生儿和专职鼻呼吸，并经常有 自发的活动(鼻胀)，尤指在头几个小时 生命，在喂养期间，并作为呼吸道的主要临床体征 苦恼。我们已经证明，在活动AS期间激活会得到增强 与安静的睡眠相比，活动的开始和高峰都在此之前 隔膜(DIA)，并导致鼻阻力减少和 吸气时咽部负压随之降低。AS AN可能影响新生儿的呼吸功和呼吸道通畅性 对于婴儿来说，了解化学和机械感受器是很重要的 与DIA相比，对这块肌肉的控制。我们计划改变 短暂的低氧血症或高氧血症单独或在 结合高碳酸血症来确定这些因素的相对作用 化学刺激对AN和DIA活性的控制。我们将更改 机械感受器持续正压气道刺激水平 压力和气道闭塞以确定伸展受体在 修改活动。后一项研究将另外进行。 在拔管前和拔管后，以确定 上呼吸道和下呼吸道的受体。我们将描述 在这两种情况下观察到的AN活动背后的生理机制 非营养性吮吸和口服喂养。在所有这些研究中，一项活动 将与DIA进行比较，以确定他们的相对反应 各种刺激的范围。对以下因素的理解 触发激活将允许我们推断生理过程 婴儿潜在的自发性鼻胀。由于数量众多 上呼吸道的呼吸肌似乎也有类似的反应。 对于某些刺激，不稳定的活动可能反映出普遍的 涉及其他上呼吸道肌肉的紊乱。现成的易用性 对临床观察和生理测量的影响 发现上呼吸道神经肌肉控制的异常 新生儿有发生阻塞性呼吸暂停发作的风险。

The alae nasi (AN) has been identified as a respiratory muscle of the upper airway that is able to alter nasal resistance and modify airflow to the lungs. Neonates and obligate nose breathers and frequently have spontaneous AN activity (nasal flaring) especially in the first hours of life, during feeding, and as a major clinical sign of respiratory distress. We have shown that AN activation is enhanced during active as compared to quiet sleep, has its onset and peak of activity prior to that of the diaphragm (DIA), and causes a reduction in nasal resistance and consequent decrease in negative pharyngeal pressure during inspiration. As the AN may influence work of breathing and airway patency in newborn infants, it is important to understand the chemical and mechanoreceptor control of this muscle in comparison to that of the DIA. We plan to alter chemosensitivity using brief periods of hypoxemia or hyperoxia alone or in combination with hypercapnia to determine the relative roles of these chemical stimuli on the control of AN and DIA activity. We will alter the level of mechanoreceptor stimulation by means of continuous positive airway pressure and airway occlusion to define the role of stretch receptors in modifying AN activity. The latter studies will be additionally performed both prior to and following extubation to determine the relative roles of receptors in the upper and lower airway. We will characterize the physiologic mechanics underlying the AN activity observed during both non-nutritive sucking and oral feeding. In all these studies, AN activity will be compared to that of the DIA to determine their relative responses to the range of various stimuli. An understanding of the factors that trigger AN activation will allow us to infer the physiologic processes underlying spontaneous nasal flaring in infants. Since numerous respiratory muscles of the upper airway appear to exhibit similar responses to certain stimuli, unstable AN activity might reflect a generalized derangement involving other upper airway muscles. The ready accessibility of the AN to both clinical observations and physiologic measurements could reveal abnormalities in the neuromuscular control of the upper airway in neonates at risk for obstructive apneic episodes.