Department of Clinical Neurophysiology, Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland. Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. Author to whom any correspondence should be addressed.
Physiol Meas. 2018 Nov 6;39(11):114004. doi: 10.1088/1361-6579/aae42c.
In obstructive sleep apnea (OSA), breathing cessations are often followed by arousals, leading to sleep fragmentation and thus impaired sleep quality. Arousals and fragmented sleep are also related to detrimental cardiovascular events. The key index for OSA diagnosis (i.e. the apnea-hypopnea index) attributes equal diagnostic value to apneas and hypopneas, despite the fact that the associated arousals and desaturations may be very different. Thus, considering the severity of the consequences of apneas and hypopneas could enhance the estimation of OSA severity. In this study, we investigate whether the probability and duration of apnea- and hypopnea-related arousals differ and whether the differences in desaturation severity following apneas and hypopneas are dependent on sleep stage.
Polysomnographic recordings of 348 consecutive OSA patients were included for analysis. The severity of arousals and desaturations associated with hypopneas within different sleep stages was compared to that of arousals and desaturations associated with apneas. In addition, the probability of arousals related to apneas and hypopneas was evaluated within OSA severity categories.
Apneas caused arousals less frequently than hypopneas in N1, N2, and N3 sleep in all OSA severity categories. However, the arousals caused by apneas were longer (p < 0.001) and the desaturations related to apneas were more severe (p < 0.001) than those related to hypopneas in N1, N2, and rapid eye movement sleep even after adjustment for respiratory event durations.
Desaturations and arousals related to apneas are more severe than those related to hypopneas. Therefore, apneas followed by arousal or desaturation should have a different diagnostic value than hypopneas when assessing OSA severity and related risk for cardiovascular consequences.
在阻塞性睡眠呼吸暂停（OSA）中，呼吸暂停通常伴随着觉醒，导致睡眠碎片化，从而降低睡眠质量。觉醒和碎片化的睡眠也与心血管不良事件有关。OSA 诊断的关键指标（即呼吸暂停低通气指数）赋予呼吸暂停和低通气同等的诊断价值，尽管相关的觉醒和饱和度下降可能非常不同。因此，考虑呼吸暂停和低通气的严重程度可以提高 OSA 严重程度的估计。在这项研究中，我们研究了与呼吸暂停和低通气相关的觉醒的概率和持续时间是否不同，以及呼吸暂停和低通气后饱和度下降的严重程度是否取决于睡眠阶段。
纳入了 348 例连续 OSA 患者的多导睡眠图记录进行分析。比较了不同睡眠阶段的低通气相关觉醒和饱和度下降与呼吸暂停相关觉醒和饱和度下降的严重程度。此外，还评估了在不同 OSA 严重程度类别中与呼吸暂停和低通气相关的觉醒的概率。
在所有 OSA 严重程度类别中，在 N1、N2 和 N3 睡眠中，呼吸暂停引起的觉醒频率低于低通气，但呼吸暂停引起的觉醒时间更长（p<0.001），与低通气相比，呼吸暂停相关的饱和度下降在 N1、N2 和快速眼动睡眠中更为严重（p<0.001），即使在调整呼吸事件持续时间后也是如此。
与呼吸暂停相关的饱和度下降和觉醒比与低通气相关的更严重。因此，在评估 OSA 严重程度和相关心血管后果风险时，呼吸暂停后觉醒或饱和度下降应具有与低通气不同的诊断价值。
