阻塞性睡眠呼吸暂停低通气综合征患者脑血管储备功能的研究

Study of cerebrovascular reserve capacity in obstructive sleep apnea-hypopnea syndrome

目的评价阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者脑血管储备能力（CVR）。方法选择114例OSAHS患者和43名健康人作为研究对象。114例OSAHS患者根据呼吸暂停低通气指数（AHI）和夜间最低血氧饱和度（LSaO2）分为轻、中、重度组。对所有受试者均采用经颅多普勒超声检测仪和CO2分压检测仪，通过吸入自身CO2气体诱导高碳酸血症、过度换气诱导低碳酸血症的方法来测定脑血管储备功能。结果中、重度OSAHS患者低碳酸血症时CVR分别为（1．80±1．34）、（1．43±1．05）％／mmHg明显低于健康对照组（2．93±0．93）％／mmHg，差异均有统计学意义（P均〈0．05）；轻度OSAHS患者CVR为（2．53±1．83）％／ramHg，与健康对照组比较差异无统计学意义（P〉0．05）。高碳酸血症时中、重度OSAHS患者CVR分别为（1．83±1．32）、（1．08±1．00）％／ramHg明显低于健康对照组（3．32±1．53）％／mmHg，差异均有统计学意义（P均〈0．05）；AHI与低、高碳酸血症脑血管储备之间呈负相关（r值分别为-0．665、-0．721；P均〈0．05）。结论吸入CO2方法可用于CVR功能的评价。CVR与AHI相关。中、重度OSAHS患者由于缺氧严重，CVR能力降低使血流动力学发生变化。

Objective To assess cerebrovascular reserve capacity in patients with obstructive sleep apnea-hypopnea syndrome（OSAHS）. Methods One hundred and fourteen patients with OSAHS and 43 normal persons were enrolled in this study. The patients were divided into mild, moderate, severe according to apnea hypopnea index （AHI） and LSaO2 （lowest arterial oxygen saturation）. All the patients and normal persons were routinely examined using transcranial Doppler （TCD） and end-tidal carbon dioxide partial pressure（ETCO2） to evaluate cerebrovascular reserve. Hypercapnia was induced by inhaling the CO2 which produced by the patients themselves, and hypocapnia was elicited by voluntary hyperventilation. Results CVR in the severe and moderate OSAHS were significantly lower than that in the control group [ （1.80 ± 1.34） %/mm Hg and （1.43 ± 1.05 ） %/mm Hg vs （2.93± 0. 93 ） %/mm Hg, P 〈 0. 05 ] when patients in the condition of hypocapnia. And there was no significant difference on CRV between the mild OSAHS group and control group [ （2. 53 ± 1.83） %/mm Hg vs （ 2. 93± 0. 93 ） %/mm Hg, P 〉 0. 051. When patients in the condition of Hypercapnia , CR. in the severe and moderate OSAHS were also significantly lower than that in the control group [ （ 1.83 ± 1.32） %/mm Hg and （1.08± 1.00）%/mm Hg vs （3.32± 1.53）%/mm Hg, P 〈 0.05）, AHI was negatively correlated with the cerebrovascular reserve at the condition of hypercapnia and hypocapnia （r=-0. 665,-0. 721;P 〈 0. 05 ）. Conclusion Inhaling CO2 is a effective method for assessing CVR. Cerebrovaseular reserve capacity is associated with AHI. Reduced CVR causes hemodynamics change being severe hypoxia in the moderate and severe OSAHS.