Adelaide Institute for Sleep Health, Repatriation General Hospital, Daw Park, South Australia 5041, Australia.
Thorax. 2010 Feb;65(2):107-12. doi: 10.1136/thx.2008.112953. Epub 2009 Oct 22.
Patients with obstructive sleep apnoea (OSA) have reduced event rates during slow wave sleep (SWS) compared with stage 2 sleep. To explore this phenomenon, ventilatory and arousal timing responses to partial and complete airflow obstruction during SWS versus stage 2 sleep were examined.
Ten patients, mean+/-SD apnoea-hypopnoea index (AHI) 49.7+/-16.5 events/h with reduced OSA frequency during SWS (SWS AHI 18.9+/-14.0 events/h) slept with an epiglottic pressure catheter and nasal mask/pneumotachograph. Patients underwent rapid continuous positive airway pressure (CPAP) dialdowns to three subtherapeutic levels and brief airway occlusions in random order.
Post-dialdown, there were marked reductions in peak flow and minute ventilation, and progressive increases in inspiratory effort (p<0.001), but with limited ventilatory recovery and no differences between sleep stages. CPAP versus peak flow relationships on the third and second to last breath pre-arousal were not different between sleep stages. Arousals occurred later and post-dialdown arousal probability was lower during SWS compared with stage 2 sleep, Cox hazard ratio (95% CI) 0.65 (0.48 to 0.88), p=0.006. During SWS occlusions, time to arousal (mean+/-SEM) was prolonged (23.0+/-2.6 vs 17.1+/-1.7 s, p=0.02). Inspiratory effort developed more rapidly (-1.0+/-0.2 vs -0.6+/-0.1 cm H(2)O/s, p=0.019) and was more negative (-28.7+/-2.7 vs -20.3+/-1.6 cm H(2)O, p<0.001) on the breath preceding arousal.
Except for a heightened ventilatory drive response during airway occlusion, airway function and ventilatory compensation to ventilatory challenge appear to be similar, but with consistently and substantially delayed arousal responses, in SWS versus stage 2 sleep.
阻塞性睡眠呼吸暂停（OSA）患者在慢波睡眠（SWS）期间的事件发生率低于 2 期睡眠。为了探讨这一现象，我们研究了 SWS 与 2 期睡眠期间部分和完全气流阻塞时的通气和觉醒时间反应。
10 例患者，平均+/-SD 呼吸暂停低通气指数（AHI）为 49.7+/-16.5 次/小时，SWS 期间 OSA 频率降低（SWS AHI 为 18.9+/-14.0 次/小时），睡眠时使用会厌压导管和鼻罩/呼吸流量传感器。患者随机接受快速持续气道正压通气（CPAP）下调至三个亚治疗水平和短暂气道阻塞。
下调后，峰流速和分钟通气量明显降低，吸气努力逐渐增加（p<0.001），但通气恢复有限，睡眠阶段之间无差异。CPAP 与第三次和倒数第二次呼吸前觉醒时的峰流速关系在睡眠阶段之间没有差异。与 2 期睡眠相比，SWS 期间觉醒时间较晚，下调后觉醒概率较低，Cox 风险比（95%CI）为 0.65（0.48 至 0.88），p=0.006。在 SWS 期间，阻塞时觉醒时间（平均值+/-SEM）延长（23.0+/-2.6 与 17.1+/-1.7 s，p=0.02）。吸气努力更快发展（-1.0+/-0.2 与-0.6+/-0.1 cm H2O/s，p=0.019），在觉醒前的呼吸中更负（-28.7+/-2.7 与-20.3+/-1.6 cm H2O，p<0.001）。
除了气道阻塞期间通气驱动反应增强外，气道功能和通气挑战时的通气补偿在 SWS 与 2 期睡眠期间似乎相似，但觉醒反应始终且显著延迟。
