EFFECT OF AIRWAY OBSTRUCTION ON DIAPHRAGMATIC FUNCTION

虽然呼吸的过度劳累是呼吸短促的主要原因 慢性阻塞性肺疾病患者的呼吸和运动耐量 肺部疾病(COPD)，呼吸肌疲劳，尤其是 的横隔膜，也可能有所贡献。因为治疗的目的是缓解 阻挠经常不成功，防止或逆转的措施 横隔膜疲劳可能允许这样的患者耐受过度的 工作量。对横隔肌的病理生理学有更深入的认识 因此，疲劳是必要的。这项提议将有助于我们的 通过探讨横隔膜疲劳的发生和恢复来认识其 暴露在过度呼吸负荷下的自发呼吸的动物。 将对兔子进行研究，因为它们的横隔膜纤维成分是 相对类似于人类的横隔膜。呼吸负荷将会是 由吸气阈值电阻提供，该电阻可调节 所需呼吸努力程度的精确量化。卑鄙的兔子 横隔膜耐力、疲劳的发展模式和 呼吸性酸中毒与疲劳横隔肌的生化特征 将会被确定。随后的实验将解决以下问题 麻醉、低氧血症和呼吸负荷的持续存在 在恢复期间的起病模式和/或从疲劳中恢复。 最后，对高、低横隔板的影响进行了研究 酸碱度或乳酸浓度对慢性阻塞性肺疾病发病和恢复的影响 将进行疲劳试验。

Although the excessive work of breathing is the major cause of shortness of breath and exercise intolerance in patients with chronic obstructive pulmonary disease (COPD), fatigue of the respiratory muscles, particularly of the diaphragm, may also contribute. Since therapy directed at relieving obstruction is frequently unsuccessful, measures to prevent or reverse diaphragmatic fatigue might allow such patients to tolerate their excessive workloads. A better understanding of the pathophysiology of diaphragmatic fatigue is therefore required. This proposal would contribute to our knowledge of diaphragmatic fatigue by exploring its onset and recovery in spontaneously breathing animals exposed to excessive respiratory loads. Rabbits will be studied because their diaphragmatic fiber composition is relatively similar to human diaphragms. The respiratory loading will be supplied by an inspiratory threshold resistor, which is adjustable for precise quantitation of degree of respiratory effort required. Mean rabbit diaphragmatic endurance, the pattern of development of fatigue and of respiratory acidosis, and biochemical features of fatigued diaphragm muscle will be determined. Subsequent experiments will address the influences of anesthesia, hypoxemia, and the continuing presence of respiratory loading during recovery on the pattern of onset and/or recovery from fatigue. Finally, investigations of the influence of high or low diaphragmatic levels of pH or lactate concentration on the onset and recovery from fatigue will be carried out.