Schulz R, Schmidt D, Blum A, Lopes-Ribeiro X, Lücke C, Mayer K, Olschewski H, Seeger W, Grimminger F
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Justus-Liebig University, 35392 Giebetaen, Germany.
Thorax. 2000 Dec;55(12):1046-51. doi: 10.1136/thorax.55.12.1046.
Reduced endothelium dependent vasodilation has been reported in patients with obstructive sleep apnoea (OSA) but direct measurements of the most potent naturally occurring vasodilator, nitric oxide (NO) or its derivatives (nitrate and nitrite, NO(x)), have not yet been performed in these patients.
In 21 patients with OSA of mean (SE) age 54 (2) years, body mass index (BMI) 30.9 (1.1) kg/m(2), and apnoea-hypopnoea index (AHI) 37 (4)/h, NO(x) levels were measured in peripheral venous blood samples by chemiluminescence. Blood samples were obtained before and after two nights of continuous positive airway pressure (CPAP) and after 5.5 (1.5) months of follow up. Thirteen age matched, healthy volunteers and 18 patients without OSA but with a similar spectrum of comorbidity served as controls (control groups 1 and 2).
Before CPAP NO(x) levels were 21.7 (1.5) microM in patients with OSA compared with 42.6 (2.2) microM and 36.7 (1.7) microM in control groups 1 and 2, respectively (p<0.01 for each comparison). NO(x) concentrations increased to 32.1 (2.7) microM after two nights of CPAP and remained constant at 32.9 (2.3) microM at follow up (p<0.01 compared with levels before CPAP).
Plasma NO(x) levels are reduced in OSA and can be increased by short and long term CPAP therapy. Although the precise mechanism underlying this observation remains to be clarified, it may have important implications for the development of cardiovascular disease in patients with OSA and for the life saving effect of CPAP.
据报道，阻塞性睡眠呼吸暂停（OSA）患者存在内皮依赖性血管舒张功能降低的情况，但尚未对这些患者直接测量最有效的天然血管舒张剂一氧化氮（NO）或其衍生物（硝酸盐和亚硝酸盐，NO(x)）。
对21例平均（标准误）年龄为54（2）岁、体重指数（BMI）为30.9（1.1）kg/m²且呼吸暂停低通气指数（AHI）为37（4）次/小时的OSA患者，通过化学发光法测量外周静脉血样本中的NO(x)水平。在持续气道正压通气（CPAP）治疗两晚前后以及随访5.5（1.5）个月后采集血样。13名年龄匹配的健康志愿者和18例无OSA但有相似合并症谱的患者作为对照（对照组1和对照组2）。
在CPAP治疗前，OSA患者的NO(x)水平为21.7（1.5）微摩尔，而对照组1和对照组2分别为42.6（2.2）微摩尔和36.7（1.7）微摩尔（每次比较p<0.01）。两晚CPAP治疗后，NO(x)浓度升至32.1（2.7）微摩尔，随访时保持在32.9（2.3）微摩尔（与CPAP治疗前水平相比p<0.01）。
OSA患者血浆NO(x)水平降低，短期和长期CPAP治疗均可使其升高。尽管这一观察结果的具体机制尚待阐明，但它可能对OSA患者心血管疾病的发生以及CPAP的救命作用具有重要意义。
