Electrical and mechanical activity of the diaphragm accompanying body position in severe chronic obstructive pulmonary disease.
Electrical and mechanical activity of the diaphragm accompanying body position in severe chronic obstructive pulmonary disease.
复制标题
严重慢性阻塞性肺疾病中膈肌伴随身体位置的电和机械活动。
DOI：
10.1164/arrd.1982.125.3.275
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
J. Sharp
中科院分区：
文献类型：
--
作者：
W. Druz;J. Sharp
采用一种特殊的胃食管导管，对8名正常受试者和6名重度慢性阻塞性肺疾病（COPD）患者在仰卧位、站立位、直立坐姿和前倾（坐位）时的横膈膜（Edi）和横膈膜压（Pdi）进行肌电图测量。4例患者采用仰卧位和/或前倾体位后，呼吸困难明显缓解。所有8名正常受试者和6名COPD患者中的4名在采取站立和直立坐姿时表现出显著（2- 5倍）增量Edi，即Edi的相位吸气幅度。在正常受试者中，4种体位均保持Pdi的相位吸气增量，而在所有COPD患者中，直立坐姿和站立姿势的Pdi均显著下降。在6例COPD患者中，2例在直立姿势时delta Edi未增加。这表明，在这些患者中，由于直立姿势时肌肉纤维缩短，通常补偿膈肌效率降低的反射没有起作用。尽管目前尚不清楚这种代偿反射抑制的机制，但从膈肌能量学的角度来看，这种反射抑制可能是有利的。因此，膜片将避免为完成疲劳的机械任务而进行能量浪费的尝试。
Using a special gastroesophageal catheter, electromyographic measurements of the diaphragm (Edi) and transdiaphragmatic pressure (Pdi) were taken in the supine, standing, erect sitting, and leaning forward (sitting) positions in 8 normal subjects and 6 patients with severe chronic obstructive pulmonary disease (COPD) with marked hyperinflation and low fat diaphragms. Four patients had pronounced postural relief of their dyspnea from assuming the supine and/or leaning forward positions. All 8 normal subjects and 4 of the 6 patients with COPD showed substantial (2- to 5-fold) increases in delta Edi, the phasic inspiratory amplitude of Edi, on assuming the standing and erect sitting postures. In the normal subjects, delta Pdi, the phasic inspiratory increment in Pdi, was maintained in all 4 postures, whereas in all patients with COPD, it decreased significantly in the erect sitting and standing postures. In 2 of the 6 patients with COPD, the delta Edi did not increase in the erect postures. This suggested that in these patients a reflex, which normally compensates for reduced diaphragmatic efficiency because of shortened muscle fibers in the erect postures, was not operating. Although it is not clear what mechanism(s) might account for suppression of this compensatory reflex, such reflex suppression might be advantageous from the viewpoint of diaphragmatic muscle energetics. The diaphragm would be thus spared energetically wasteful attempts to accomplish a fatiguing mechanical task.