DEVELOPMENTAL DETERMINANTS OF UPPER AIRWAY COLLAPSIBILITY

儿童打鼾比成人少，阻塞性呼吸暂停也少，这表明上呼吸道不容易塌陷。 因此，我们假设，由于上气道结构和呼吸驱动的变化，上气道对负压负荷的代偿性反应随年龄的增长而降低。 我们测量了20名无打鼾、非肥胖儿童和成人睡眠期间上气道上游压力/流量关系。通过将最大吸气气流与通过面罩施加的鼻压水平相关联来进行测量。 上游压力/流量曲线（SPF）的斜率用于表征上气道功能。 结果表明，儿童的SPF值比成人的SPF值（8 ± 5vs 30 ± 18 ml/s/cm H2O，P < 0.002）要小，SPF值与年龄（r = 0.62，P < 0.01）和体重指数（r = 0.62，P < 0.01）相关。 6例儿童和2例成人睡眠100毫秒内的闭合压力（P0.1）与SPF呈负相关（r =-0.80，N = 8; P < 0.02）。 我们的结论是，上气道代偿反应低于大气压负荷降低与年龄。 这与体重指数增加有关，即使在不打鼾、不肥胖的受试者中也是如此。睡眠期间的通气驱动在调节上气道反应中起作用。 进一步的研究将评估高碳酸血症对上呼吸道反射的发育反应。

Children snore less than adults, and have fewer obstructive apneas, suggesting a less collapsible upper airway. We therefore hypothesized that the compensatory upper airway responses to subatmospheric pressure loading decrease with age, due to changes in upper airway structure and ventilatory drive. We measured upper airway upstream-pressure/flow relationships during sleep in 20 non-snoring, non-obese children and adults. Measurements were made by correlating maximal inspiratory airflow with the level of nasal pressure applied via a mask. The slope of the upstream-pressure/flow curve (SPF) was used to characterize upper airway function. We found that children had a flatter slope than adults (8 + 5 vs 30 + 18 ml/s/cm H2O, P < 0.002), and that SPF correlated with age (r = 0.62, P < 0.01) and body mass index (r = 0.62, P < 0.01). The occlusion pressure in 100 milliseconds (P0.1) during sleep was measured in 6 children and 2 adults; it correlated inversely with SPF (r = -0.80, N = 8; P < 0.02). We conclude that the upper airway compensatory responses to subatmospheric pressure loading decrease with age. This is associated with increased body mass index, even in non-snoring, non-obese subjects. Ventilatory drive during sleep plays a role in modulating upper airway responses. Further studies will evaluate the developmental response of hypercapnia on upper airway reflexes.