阻塞性睡眠呼吸暂停低通气综合征患者膈肌对经颅磁刺激的反应

目的 探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者经颅磁刺激(TMS)膈肌运动诱发电位(MEP)的变化及可能机制.方法 2005年6月至2006年6月就诊广州医学院第一附属医院呼吸疾病研究所的健康体检者及鼾症患者,分为健康对照组16例,单纯鼾症组7例,OSAHS轻中度组13例及重度组16例,均使用TMS结合经颈椎棘突磁刺激(CMS)及多导食管电极测定右侧膈肌MEP的潜伏期、幅值和中枢运动传导时间(CMCT),5例OSAHS患者经有效鼻持续气道正压通气(nCPAP)治疗超过2个月后复查上述指标.采用SPSS 12.0统计软件进行数据分析,检测结果 以x±s表示.结果 OSAHS重度组右侧膈肌MEP的幅值为(152±116)μV,明显低于健康对照纽的(414±201)μV、单纯性鼾症组的(352±99)μV及OSAHS轻中度组的(372±206)μV;其膈肌MEP的潜伏期和CMCT分别为(18.1±1.8)和(10.6±1.8)ms,与健康对照组的(13.9±1.6)和(7.7±1.7)ms相比,单纯性鼾症组的(14.6±1.6)和(8.1±1.6)ms以及轻中度组的(15.4±2.7)和(9.0±2.2)ms明显延长.膈肌MEP的幅值、潜伏期及CMCT与微醒觉指数、呼吸暂停最长时间、夜间最低脉搏容积血氧饱和度(SpO2)、低氧指数、SpO2<90%占总睡眠时间比例以及呼吸暂停低通气指数(AHI)均具有相关性.5例重度OSAHS患者经nCPAP治疗超过2个月后,膈肌MEP的潜伏期较治疗前缩短,分别为(17.5±0.6)和(15.5±0.7)ms.结论 OSAHS患者膈肌MEP的潜伏期和CMCT均延长,而MEP的振幅降低,这些变化可能与反复夜间低氧、二氧化碳潴留及睡眠结构紊乱有关.

Study of transcranial magnetic stimulation on diaphragm in patients with obstructive sleep apnea-hypopnea syndrome

Objective To investigate the changes and possible mechanisms of diaphragm motor evoked potential(MEP) elicited by transcranial magnetic stimulation(TMS) in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods Sixteen healthy volunteers (control group), 7 primary snorers (snore group),13 mild-moderate OSAHS patients (mild-moderate group) and 16 severe OSAHS patients (severe group ) were recruited for the study from June in 2005 to June in 2006.Esophageal electrodes combined with TMS and cervical magnetic stimulation (CMS) were used to measure the latency and amplitude of right diaphragm MEP,as well as central motor conduction time (CMCT). The study was repeated in 5 OSAHS pat ients after effective nasal continuous positive airway pressure (nCPAP) treatment for at least 2 months. Results Theamplitude of right MEP in severe OSAHS group was ( 152 ± 116) μV,which was significantly lower than that in the control group (414 ±201 ) μV, the snore group (352 ± 99 ) μV and the mild-moderate group (372±206) μV. The latency and CMCT in the severe OSAHS group were ( 18.1 ± 1.8 ),( 10.6 ± 1.8 ) ms respectively, which were significantly longer than those in the control group(13.9±1.6), (7.7±1.7) ms, the snore group (14.6±1.6),(8.1 ±1.6) ms, and the mild- moderate group (15.±2. 7),(9. 0 ±2. 2) ms. The latency and amplitude of diaphragm MEP as well as CMCT correlated significantly with arousal index,longest apnea duration, minimum pulse oxygen saturation (SpO2),oxygen desaturation index,the percentage of total sleep time with SpO2 below 90% and apnea- hypoxea index(AHI).The latency became significantly shorter after effective nCPAP treatment for more than 2 months, which was(17.5±0.6)and(15.5±0.7)ms respectively.Conclusions The Iateney of MEP and CMCT in OSAHS patients prolonged significantly，while the amplitude of MEP lowered.which may be due to repeated hypoxia,carbon dioxide retention and disorder of sleep structure at night.