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膈肌是主要的呼吸肌,我们设想膈肌疲劳可能会导致呼吸中枢驱动增高以维持正常的通气功能。为验证这一假说,我们在6名健康人身上记录膈肌疲劳前后所进行的二氧化碳重复呼吸时的食道膈肌肌电压。采用具有4个电极对的多导食道电极导管记录膈肌电压,同时用胃食道球管法记录磁刺激下的食道、胃和跨膈肌电压。运用最新发展的食道电极定位法,在功能残气下进行双侧颈前磁刺激(BAMPS)诱发膈肌复合肌肉动作电位,并根据所诱发动作电位的幅值及极性,将多导食道电极准确地置放于膈肌水平。膈肌疲劳分别通过2 min 最大自主通气(MVV)以及在阻力负荷下反复最大用力吸气诱发。经过2 min 最大自主通气或阻力负荷下反复最大用力吸气后,所有受试者均出现膈肌疲劳:2 min 最大自主通气后BAMPS 诱发的跨膈肌电压平均下降22%(13%～27%);负荷下反复最大用力吸气后 BAMPS 诱发的跨膈肌压下降20%(13%～26%)。不论膈肌疲劳前还是疲劳后所进行的二氧化碳重复呼吸,分钟通气量与膈肌电压均呈线性相关。
Diaphragmatic muscle is the main respiratory muscle, and we hypothesize that diaphragmatic fatigue may lead to increased respiratory center drive to maintain normal ventilatory function. To test this hypothesis, we recorded the esophageal diaphragmatic muscle voltage on repeated breathing of carbon dioxide before and after diaphragmatic fatigue on 6 healthy individuals. Diaphragm voltages were recorded using a multi-channel esophageal catheter with 4 electrode pairs, while esophageal, gastric and diaphragmatic voltages were recorded by gastrogavage. Using the newly developed esophageal electrode localization method, bilateral anterior cervical magnetic stimulation (BAMPS) -based muscle action potentials were induced under functional residual gas. According to the amplitude and polarity of induced action potentials, the multi-channel esophageal electrodes were accurately Place on the diaphragm level. Diaphragm fatigue was induced by maximal voluntary ventilation (MVV) at 2 min and maximal forced inspiration at resistance load, respectively. Diaphragmatic fatigue was observed in all subjects after 2 min of maximum autonomic ventilation or repeated maximal forced inspiration under resistance load: mean BAMPS-induced trans diaphragm voltage decreased by 22% (13% -27%) on average after 2 min of maximal voluntary ventilation; BAMPS-induced diastolic diastolic depression decreased by 20% (13% -26%) after maximum maximal forced inhalation. Diaphragmatic muscle fatigue before or after repeated carbon dioxide breathing, minute ventilation and diaphragm voltage showed a linear correlation.