Alpert Medical School of Brown University, Memorial Hospital of Rhode Island, Pawtucket, Rhode Island.
J Clin Sleep Med. 2017 Aug 15;13(8):941-947. doi: 10.5664/jcsm.6690.
As lung volume decreases radial traction on the upper airway is reduced, making it more collapsible. The purpose of this study was to measure change in end-expiratory lung volume (EELV) following sleep onset and to evaluate the relationship between change in EELV and sleep-disordered breathing.
Twenty subjects underwent overnight polysomnography, of whom 14 (70%) had obstructive sleep apnea (OSA). Change in EELV was measured throughout the night using magnetometry. Sleep was staged and respiratory events scored using American Academy of Sleep Medicine criteria. An additional 10 subjects had change in EELV measured simultaneously by magnetometer and spirometer while awake.
In the subjects studied while awake, change in EELV calculated from magnetometer data correlated very strongly ( = 0.89, < .001) with that obtained by spirometry. In the 20 subjects who underwent polysomnography, there was a decline in EELV for sleep stages N1, N2, N3, and R (REM sleep); 17.9 ± 121.0 mL (mean ± standard deviation), 228.5 ± 151.8 mL, 198.1 ± 122.1 mL, and 316.7 ± 131.9 mL, respectively. Mean EELV reduction during stage R sleep doubled that noted during non-stage R sleep (316.7 ± 131.9 mL versus 150.9 ± 89.7 mL, respectively) ( < .001). The difference in EELV between non-stage R and stage R sleep inversely correlated with mean oxygen saturation ( = -0.56, = .06). EELV reduction in individuals with moderate and severe OSA was greater than in those with mild SDB but did not reach statistical significance.
Magnetometry provides a precise, unobtrusive, and continuous means to study lung volume changes during sleep. EELV declines from sleep onset, reaching its nadir during stage R sleep. The reduction in EELV in stage R sleep was associated with lower mean oxygen saturation but was not associated with greater sleep-disordered breathing.
随着肺容积的减少，对上气道的径向牵引力减小，使气道更易塌陷。本研究的目的是测量睡眠起始后呼气末肺容积（EELV）的变化，并评估 EELV 变化与睡眠呼吸障碍之间的关系。
20 名受试者接受了一整夜的多导睡眠图检查，其中 14 名（70%）患有阻塞性睡眠呼吸暂停（OSA）。使用磁力计整夜测量 EELV 的变化。使用美国睡眠医学学会标准对睡眠分期和呼吸事件进行评分。另外 10 名受试者在清醒时同时使用磁力计和肺活量计测量 EELV 的变化。
在清醒状态下进行研究的受试者中，从磁力计数据计算得出的 EELV 变化与通过肺活量计获得的 EELV 变化非常相关（ = 0.89，<.001）。在接受多导睡眠图检查的 20 名受试者中，N1、N2、N3 和 REM（快速眼动）睡眠阶段的 EELV 下降；分别为 17.9 ± 121.0 mL、228.5 ± 151.8 mL、198.1 ± 122.1 mL 和 316.7 ± 131.9 mL。REM 睡眠阶段的平均 EELV 减少量是非 REM 睡眠阶段的两倍（316.7 ± 131.9 mL 与 150.9 ± 89.7 mL，分别）（<.001）。非 REM 睡眠和 REM 睡眠之间 EELV 的差异与平均氧饱和度呈负相关（ = -0.56， =.06）。中重度 OSA 个体的 EELV 减少量大于轻度 SDB 个体，但无统计学意义。
磁力计提供了一种精确、非侵入性和连续的方法来研究睡眠期间肺容积的变化。EELV 从睡眠开始时下降，在 REM 睡眠时达到最低点。REM 睡眠时 EELV 的减少与平均氧饱和度降低有关，但与睡眠呼吸障碍的严重程度无关。
