Man W D-C, Hopkinson N S, Harraf F, Nikoletou D, Polkey M I, Moxham J
Respiratory Muscle Laboratory, Guy's, King's and St Thomas' School of Medicine, King's College Hospital, Bessemer Road, London SE5 9PJ, UK.
Thorax. 2005 Sep;60(9):718-22. doi: 10.1136/thx.2005.040709. Epub 2005 May 27.
Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls.
Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables.
Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI -17.9 to -4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H(2)O v 204.8 cm H(2)O; 95% CI -5.4 to 50.6; p = 0.11).
Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes.
股四头肌无力在慢性阻塞性肺疾病（COPD）中很常见，但在手部小肌肉（拇收肌）中未观察到。虽然这可以通过股四头肌活动减少来解释，但该观察结果也可以通过肌肉的解剖位置或纤维类型组成来解释。然而，腹肌在解剖结构和纤维类型分布上与股四头肌相似，尽管它们在COPD中仍保持活跃。咳嗽胃内压是一种最近描述的技术，比传统技术更准确地评估腹肌（从而呼气肌）力量。进行了一项研究，以检验与健康老年对照相比，COPD患者股四头肌比腹肌存在更严重无力这一假设。
对43例稳定期COPD患者和25名在人体测量变量上匹配的健康老年志愿者测量最大咳嗽胃内压和股四头肌等长力量。
尽管COPD患者股四头肌平均力量显著降低（29.9千克对41.2千克；95%可信区间-17.9至-4.6；p = 0.001），但咳嗽胃内压在COPD患者中得以保留（227.3厘米水柱对204.8厘米水柱；95%可信区间-5.4至50.6；p = 0.11）。
在股四头肌无力的情况下，稳定期COPD门诊患者的腹肌力量得以保留。这表明解剖位置和纤维类型不能解释COPD患者的股四头肌无力。由此推断，我们得出结论，废用及随之而来的身体机能下降是COPD患者股四头肌无力发展的重要因素，或者活动可保护腹肌免受可能的全身性肌病过程影响。
