Pulmonary Function and Exercise Physiology Laboratory, Respiratory Care Department, University of Arizona, Tucson, AZ; Division of Pulmonary and Critical Care Medicine, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA.
Division of Pulmonary and Critical Care Medicine, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
Chest. 2015 Oct;148(4):986-994. doi: 10.1378/chest.14-2878.
In COPD, a decreased inspiratory capacity to total lung capacity ratio (IC/TLC) is associated with dynamic hyperinflation and poor exercise capacity. The association with upper-extremity force measured by handgrip strength (HGS) and 6-min walk distance (6MWD) has not been previously described. We hypothesized that IC/TLC affects muscle strength in the upper and lower extremities, affecting HGS and 6MWD.
We prospectively measured lung function, HGS, and 6MWD in 27 patients with COPD and 12 healthy nonsmokers twice, 1 year apart. The patients were classified according to level of hyperinflation: IC/TLC > 25% or IC/TLC ≤ 25%.
Patients with COPD had reduced lung function, static hyperinflation, and reduced HGS and 6MWD compared with the control subjects on both evaluations (P < .01). There was a statistically significant deterioration in HGS, IC/TLC, and 6MWD after 1-year follow-up in the COPD compared with the control group (P < .001). More hyperinflation (IC/TLC < 0.25) was associated with lower HGS and 6MWD (P < .001). Changes in IC/TLC correlated with changes in HGS (r = 0.429, P < .05). Multivariate analysis determined that IC/TLC is an independent factor associated with HSG and 6MWD.
HGS and 6MWD are reduced in patients with COPD, particularly in those with hyperinflation and evidence of longitudinal deterioration not seen in control subjects. This finding suggests that resting hyperinflation may exert a detrimental effect on cardiac function and plays a role in reduced exercise performance in patients with COPD.
在 COPD 中，吸气量与肺总量的比值（IC/TLC）降低与动态过度充气和运动能力差有关。但尚未描述其与手握力（HGS）和 6 分钟步行距离（6MWD）测量的上肢力量之间的关系。我们假设 IC/TLC 会影响上下肢的肌肉力量，从而影响 HGS 和 6MWD。
我们前瞻性地测量了 27 例 COPD 患者和 12 例健康不吸烟者的肺功能、HGS 和 6MWD，两次测量间隔 1 年。根据过度充气程度将患者分为 IC/TLC＞25%或 IC/TLC≤25%两组。
与对照组相比，COPD 患者的肺功能、静态过度充气、HGS 和 6MWD 均降低（P＜0.01）。与对照组相比，COPD 患者在 1 年随访时 HGS、IC/TLC 和 6MWD 均有统计学意义的恶化（P＜0.001）。过度充气（IC/TLC＜0.25）与 HGS 和 6MWD 降低相关（P＜0.001）。IC/TLC 的变化与 HGS 的变化相关（r=0.429，P＜0.05）。多变量分析确定 IC/TLC 是与 HSG 和 6MWD 相关的独立因素。
COPD 患者的 HGS 和 6MWD 降低，尤其是在那些有过度充气和纵向恶化的患者中，而在对照组中则没有观察到这种变化。这一发现表明，静息过度充气可能对心脏功能产生有害影响，并在 COPD 患者运动能力下降中发挥作用。
