VENTILATORY RESPONSES IN THE OBSTRUCTIVE SLEEP APNEA SYNDROME

阻塞性睡眠呼吸暂停综合征（OSAS）是儿童发病的重要原因。对这种常见而重要的疾病的病理生理学知之甚少。我们假设OSAS患儿在通气驱动和/或唤醒反应方面存在异常，从而导致上呼吸道阻塞。现已公布的初步数据显示，患有阻塞性睡眠呼吸暂停症的儿童对高碳酸血症的觉醒反应减弱。在方案的第二部分，唤醒和呼吸反应吸气阻力负荷（IRL）进行了测试。OSAS患儿在负荷下的唤醒率高于对照组（23 + 8 vs 15 + 7 cm H2O/L/s, P < 0.05）。OSAS患者在快速眼动期（REM）的唤醒阈值高于非快速眼动期（P < 0.001），而正常人在快速眼动期（REM）的唤醒阈值较低（P < 0.005）。在对照组中评估对IRL的通气反应。在IRL为15 cm H2O/L/min时，潮气量立即（为基线的56 + 17%，P < 0.001）和IRL 3分钟后（67 + 23%,P < 0.005）均有显著下降。占空比增加。我们得出结论，OSAS儿童对IRL的唤醒反应受损。正常儿童在睡眠时对IRL只有部分通气代偿。然而，唤醒发生在IRL导致气体交换异常之前。儿童的反应与成人不同。我们推测对IRL的异常唤醒反应可能在儿童阻塞性睡眠呼吸暂停的病理生理中起作用。

The obstructive sleep apnea syndrome (OSAS) is a significant cause of morbidity in children. Little is known about the pathophysiology of this common and important disease. We hypothesized that children with OSAS have abnormalities in their ventilatory drive and/or arousal responses, which contribute to upper airway obstruction. Initial data, which have now been published, showed that children with OSAS have blunted arousal responses to hyercapnia. In the second part of the protocol, arousal and ventilatory responses to inspiratory resistance loading (IRL) were tested. Children with OSAS aroused at a higher load than controls (23 + 8 vs 15 + 7 cm H2O/L/s, P < 0.05). Patients with OSAS had higher arousal thresholds during rapid eye movement (REM) vs nonREM sleep (P < 0.001), whereas normal subjects had lower arousal thresholds during REM (P < 0.005). Ventilatory responses to IRL were evaluated in the controls. There was a marked decrease in tidal volume both immediately (56 + 17% of baseline at an IRL of 15 cm H2O/L/min, P < 0.001) and after 3 minutes of IRL (67 + 23%, P < 0.005). The duty cycle increased. We conclude that children with OSAS have impaired arousal responses to IRL. Normal children have only partial ventilatory compensation for IRL during sleep. However, arousal occurs before IRL results in gas exchange abnormalities. The response in children differs from adults. We speculate that abnormal arousal responses to IRL may play a role in the pathophysiology of childhood obstructive sleep apnea.