Khoo M C, Shin J J, Asyali M H, Kim T S, Berry R B
Biomedical Engineering Department, University of Southern California, Los Angeles 90089-1451, USA.
Respir Physiol. 1998 Jun;112(3):291-303. doi: 10.1016/s0034-5687(98)00041-3.
The hyperpnea that accompanies arousal at the end of obstructive apnea is believed to be due to the progressive build-up in chemical drive during the apnea and a state-related decrease in upper airway resistance. We postulated the existence of a third component: a state-related transient increase in neural drive to the ventilatory pump muscles. To quantify this contribution, we measured the ventilatory response to arousal (VRA) in eight patients with obstructive sleep apnea (OSA) during continuous positive airway pressure (CPAP) therapy, applied at individually titrated levels. CPAP application reduced total pulmonary resistance (RL) to approximately normal levels, stabilizing ventilation and sleep state. Transient arousal from stage 2 sleep was induced using 5-sec tones (60-90 dB). Mean inspiratory flow increased above control on the second and third post-arousal breaths (P < 0.05), with a peak increase of 7.8 +/- 2.9 L/min while the accompanying changes in RL were significant. The time-course of VRA measured in three normal subjects under CPAP was similar to that observed in the OSA patients. However, elimination of CPAP prolonged the VRA time-course. Taken together, these findings demonstrate that: (1) during arousal, the increase in state-related neural respiratory drive is short-lived but not substantial; and (2) the resulting VRA time-course is shaped by the dynamics of the upper airway response to arousal.
阻塞性呼吸暂停末期伴随觉醒出现的呼吸急促被认为是由于呼吸暂停期间化学驱动的逐渐增强以及与状态相关的上气道阻力降低。我们推测存在第三个因素：与状态相关的通气泵肌肉神经驱动的短暂增加。为了量化这一因素的作用，我们在八名阻塞性睡眠呼吸暂停（OSA）患者接受持续气道正压通气（CPAP）治疗期间，以个体化滴定水平应用CPAP时，测量了其对觉醒的通气反应（VRA）。应用CPAP可将总肺阻力（RL）降低至大致正常水平，稳定通气和睡眠状态。使用5秒时长的音调（60 - 90分贝）诱导从第二阶段睡眠中短暂觉醒。觉醒后第二和第三次呼吸时平均吸气流量高于对照水平（P < 0.05），峰值增加7.8 +/- 2.9升/分钟，同时伴随的RL变化显著。在CPAP条件下对三名正常受试者测量的VRA时间进程与在OSA患者中观察到的相似。然而，去除CPAP会延长VRA时间进程。综上所述，这些发现表明：（1）在觉醒期间，与状态相关的神经呼吸驱动增加是短暂的，但幅度不大；（2）由此产生的VRA时间进程由上气道对觉醒反应的动力学所塑造。
