阻塞性睡眠呼吸暂停低通气综合征患者睡眠过程中呼吸力学的变化

The changes of respiratory mechanics in patients with obstructive sleep apnea-hypopnea syndrome during sleep

目的研究阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者在睡眠过程中的呼吸力学变化特点。方法60例疑似OSAHS患者及21例无OSAHS临床表现的志愿者人选本研究，其中男70例，女11例，平均年龄（44±13）岁。所有受试者均接受整夜多导睡眠图监测，并同时采用面罩旁气流技术动态描记整个睡眠过程中的呼吸力学指标和潮气量流速容量环（TBFVL）。根据呼吸暂停低通气指数（AHI）将入选者分为OSAHS组（AHI≥15次/h）54例和对照组（AHI〈15次/h）27例。采用重复测量方差分析比较OSAHS组各期潮气吸气容积（VTI）/潮气呼气容积（VTE）及对照组各期呼吸力学指标变化；自身比较采用配对t检验；组间比较采用X。检验。结果清醒状态下呼吸周期的VTI/VTE为0.99±0.04，说明吸气和呼气潮气量大致相等。OSAHS组发生睡眠呼吸暂停后第1个呼吸周期VYI/VTE。（1.37±0.18）明显升高，在睡眠呼吸暂停前5次内和最后一次呼吸周期VTI/VTE均值（0.86±0.08和0.72±0.19）明显降低，说明呼吸暂停前一段时间内呼气量明显多于吸气量，而呼吸暂停后吸气量多于呼气量。OSAHS组无呼吸事件浅睡眠期VTI（463±122）mL]、VTE[（466±127）ml]和分钟通气量[（6.4±1.6）L/min]比睡前[（554±134）ml、（565±147）ml和（8.3±1.9）L/min]明显减少。TBFVL结果显示，OSAHS组吸气阻力升高者占100％（54/54），呼气阻力升高者和两种阻力同时升高者均占96.3％（52/54）。结论在发生睡眠呼吸暂停前OSAHS患者呼气量明显多于吸气量，直至呼吸停止，这使患者发生睡眠呼吸暂停前的功能残气量明显减少，从而上气道更加狭窄，此病理生理过程在OSAHS整个发病过程中占有重要地位。OSAHS患者浅睡眠期的潮气量和通气量较睡前降低，睡眠过程中以上气道吸气相阻力升高为主的同时普遍存在呼气相阻力升高。

Objective To study the changes of respiratory mechanics in patients with obstructive sleep apnea hypopnea syndrome （OSAHS） during sleep. Methods Eighty-one consecutive subjects, 70 males and 11 females, mean age （43.9 ± 12.6） , were recruited in this study. The respiratory mechanics during sleep were studied by using the side stream spirmeter （SSS） technique. All subjects underwent respiratory mechanics monitoring with Novametrix Medical Systems （ connected with full face mask） during nocturnal polysomnographie （PSG） study. Then by the apnea-hypopnea index （AHI） , the subjects were divided into the OSAHS group （AHI≥ 15/h） and the control group （AHI 〈 15/h）. Results Fifty-four subjects were confirmed to have OSAHS [AHI = （57.6±24. 9） hi by PSG, and 27 as the control group [ AHI = （4. 4±4. 1 ） hi. In the OSAHS group, inspiratory tidal volume/expiratory tidal volume （VTI/VTE） was 1.37± 0. 18 during the first respiratory cycle after apnea, which was significantly greater than that （0. 99±0. 04） during wakefulness. The mean VTI/VTE （0. 86±0. 09） during the 5 respiratory cycles and that （ 0.72 ± 0. 19 ） of the last respiratory cycle before the next apnea decreased significantly. These indicated that the functional residual capacity （FRC） and upper airway size were reduced gradually before apnea. Compared with the measurements before sleep, VTI [ （463± 122） ml vs （554 ± 134） ml], VTE [ （466 ± 127） ml vs （565 ± 147） ml], and expired minute volume [ （6.4±1.6） L/min vs （8.3±1.9） L/mini were decreased significantly during light sleep without apnea. Tidal breath flow-volume loop showed that in the OSAHS group, the inspiratory resistance increased in 54 patients （100%）, the expiratory resistance increased in 52 （96.3% ）, and both of them increased in 52 （96..3% ）. Conclusions OSAHS patients exhaled more air than inhaled gradually before apnea onset, and then this change was compensated by inhaling more air than exhaled in the first respiratory cycle following apnea. These resulted in decreases in FRC and upper airway size, which may play an important role in the pathophsiological mechanisms of sleep apnea. The tidal volume decrease suggested that the breathing drive was reduced in light sleep of OSAHS. In addition, a rise of both inspiratory and expiratory resistance was evident in a majority of patients with OSAHS.