EFFECT OF AIRWAY OBSTRUCTION ON DIAPHRAGMATIC FUNCTION

虽然过度的呼吸功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不耐受 肺疾病（COPD）、呼吸肌疲劳，特别是 也可能有贡献。 因为治疗旨在缓解 阻碍往往是不成功的，防止或扭转措施 运动性疲劳可能使这些患者能够忍受他们的过度疲劳。 工作量。 更好地理解脑梗死的病理生理学 因此需要疲劳。 这项建议将有助于我们 通过探讨运动性疲劳的发生和恢复， 暴露于过度呼吸负荷的自主呼吸动物。 将研究兔子，因为它们的脑纤维组成是 与人体横膈膜相似 呼吸负荷将是 由吸气阈值电阻器提供，该吸气阈值电阻器可调节， 所需呼吸努力程度的精确定量。 平均兔 耐力，疲劳和疲劳的发展模式， 呼吸性酸中毒和疲劳膈肌的生化特征 将被确定。 随后的实验将解决的影响， 麻醉、低氧血症和呼吸负荷的持续存在 在恢复期间，根据疲劳发作和/或恢复的模式。 最后，研究了高、低分子量的影响， 开始和恢复时的pH值或乳酸盐浓度水平 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.