Carter R, Nicotra B, Blevins W, Holiday D
Department of Medicine, University of Texas Health Center, Tyler 75708.
Chest. 1993 Mar;103(3):745-50. doi: 10.1378/chest.103.3.745.
Patients with advanced COPD have significantly reduced gas exchange and pulmonary function; however, little is known regarding physical work capacity and exercise gas exchange in patients with mild COPD. A total of 39 individuals (20 men and 19 women) without evidence of COPD (controls) and 51 individuals (29 men and 22 women) with mild COPD (FEV1 > or = 60 percent of predicted; and ratio of FEV1 over forced vital capacity of 60 to 70 percent) were tested to determine resting pulmonary function and resting and peak exercise gas exchange in response to progressive maximal cycle ergometer testing. In general, those with mild COPD had similar smoking histories and essentially equivalent resting gas exchange studies as compared to the controls. Measured maximal oxygen consumption was less in both the male (p < 0.003) and the female patients (p < 0.001). This was due, in part, to a lower maximal ventilation in the men with obstruction (p < 0.04), resulting from a significant reduction in tidal volume (p < 0.05). Women presented with similar decreases in maximal ventilation (p < 0.04) and maximal tidal volume (p < 0.01), while no difference in maximal respiratory rate was noted in either group (p > 0.05). Breathing reserve was 32 percent and 53 percent less for the male and female patients with obstruction than for controls. Maximal heart rates were less in the individuals with obstruction, where they reached 93 percent (p < 0.02) and 96 percent (p < 0.003) of the age- and sex-specific maximal heart rates for men and women as compared to 101 percent and 99 percent obtained in the controls. Achieved absolute work loads for men and women (in kilogram.meters per minute) were lower in the groups with obstruction (p < 0.002 and 0.0003) as well. These results demonstrate that work capacity and gas exchange are significantly decreased in individuals with even mild COPD. The reduction in functional work capacity is secondary to a loss of pulmonary function, as well as chronic deconditioning. Increased dyspnea may be responsible for the premature cessation of exercise observed in patients with mild COPD. Thus, early intervention with exercise training may be warranted to counter the deleterious effects of deconditioning and declining pulmonary function in patients with mild COPD.
重度慢性阻塞性肺疾病（COPD）患者的气体交换和肺功能显著降低；然而，对于轻度COPD患者的体力工作能力和运动气体交换情况却知之甚少。共有39名无COPD证据的个体（20名男性和19名女性，作为对照组）以及51名轻度COPD患者（29名男性和22名女性，FEV1≥预测值的60%；FEV1与用力肺活量的比值为60%至70%）接受了测试，以确定静息肺功能以及在进行递增式最大运动功率计测试时的静息和峰值运动气体交换情况。总体而言，与对照组相比，轻度COPD患者有相似的吸烟史且静息气体交换研究结果基本相当。男性（p<0.003）和女性患者（p<0.001）的实测最大摄氧量均较低。这部分是由于阻塞性男性患者的最大通气量较低（p<0.04），这是由潮气量显著降低（p<0.05）所致。女性患者的最大通气量（p<0.04）和最大潮气量（p<0.01）也有类似程度的降低，而两组的最大呼吸频率均无差异（p>0.05）。阻塞性男性和女性患者的呼吸储备分别比对照组低32%和53%。阻塞性个体的最大心率较低，男性和女性分别达到其年龄和性别特异性最大心率的93%（p<0.02）和96%（p<0.003），而对照组分别为101%和99%。阻塞性组中男性和女性达到的绝对工作量（以千克·米/分钟计）也较低（p<0.002和0.0003）。这些结果表明，即使是轻度COPD患者，其工作能力和气体交换也显著下降。功能工作能力的降低继发于肺功能丧失以及慢性失健状态。呼吸困难加剧可能是轻度COPD患者运动过早终止的原因。因此，可能有必要对轻度COPD患者尽早进行运动训练干预，以对抗失健状态和肺功能下降的有害影响。
