Cui Liwei, Ji Xiuli, Xie Mengshuang, Dou Shuang, Wang Wei, Xiao Wei
Department of Respiratory Disease, Qilu Hospital, Shandong University.
Department of Pulmonary Disease, Jinan Traditional Chinese Medicine Hospital, Jinan, People's Republic of China.
Int J Chron Obstruct Pulmon Dis. 2017 Sep 30;12:2823-2830. doi: 10.2147/COPD.S142016. eCollection 2017.
Since forced expiratory volume in 1 second (FEV) shows a weak correlation with patients' symptoms in COPD, some volume parameters may better reflect the change in dyspnea symptoms after treatment. In this article, we investigated the role of inspiratory capacity (IC) on dyspnea evaluation among COPD patients with or without emphysematous lesions.
In this prospective study, 124 patients with stable COPD were recruited. During the baseline visit, patients performed pulmonary function tests and dyspnea evaluation using the modified Medical Research Council (mMRC) scale. Partial patients underwent quantitative computerized tomography scans under physicians' recommendations, and emphysematous changes were assessed using the emphysema index (EI; low attenuation area [LAA]% -950). These subjects were then divided into the emphysema-predominant group (LAA% -950≥9.9%) and the non-emphysema-predominant group (LAA% -950<9.9%). After treatment for ~1 month, subjects returned for reevaluation of both pulmonary function parameters and dyspnea severity. Correlation analysis between the change in IC (ΔIC) and dyspnea (ΔmMRC) was performed.
Correlation analysis revealed that ΔIC was negatively correlated with ΔmMRC (correlation coefficient [cc], -0.490, <0.001) in the total study population, which was stronger than that between ΔFEV and ΔmMRC (cc, -0.305, =0.001). Patients with absolute ΔmMRC >1 were more likely to exhibit a marked increase in IC (≥300 mL) than those with absolute ΔmMRC ≤1 (74.36% versus 35.29%; odds ratio [OR], 5.317; <0.001). In the emphysema-predominant group, only ΔIC strongly correlated with ΔmMRC (cc, -0.459, =0.005), while ΔFEV did not (>0.05).
IC could serve as an effective complement to FEV in COPD patients undergoing dyspnea evaluation after treatment. For COPD patients with predominant emphysematous lesions, an increase in IC is particularly more suitable for explaining dyspnea relief than FEV.
由于慢性阻塞性肺疾病（COPD）患者一秒用力呼气容积（FEV）与症状的相关性较弱，一些容积参数可能能更好地反映治疗后呼吸困难症状的变化。在本文中，我们研究了吸气容量（IC）在有或无肺气肿病变的COPD患者呼吸困难评估中的作用。
在这项前瞻性研究中，招募了124例稳定期COPD患者。在基线访视期间，患者进行肺功能测试，并使用改良的医学研究委员会（mMRC）量表进行呼吸困难评估。部分患者根据医生建议接受定量计算机断层扫描，并使用肺气肿指数（EI；低衰减区[LAA]%-950）评估肺气肿变化。然后将这些受试者分为以肺气肿为主的组（LAA%-950≥9.9%）和非以肺气肿为主的组（LAA%-950<9.9%）。经过约1个月的治疗后，受试者返回进行肺功能参数和呼吸困难严重程度的重新评估。对IC变化（ΔIC）与呼吸困难（ΔmMRC）进行相关性分析。
相关性分析显示，在整个研究人群中，ΔIC与ΔmMRC呈负相关（相关系数[cc]，-0.490，<0.001），这一相关性强于ΔFEV与ΔmMRC之间的相关性（cc，-0.305，=0.001）。绝对ΔmMRC>1的患者比绝对ΔmMRC≤1的患者更有可能出现IC显著增加（≥300 mL）（74.36%对35.29%；优势比[OR]，5.317；<0.001）。在以肺气肿为主的组中，只有ΔIC与ΔmMRC密切相关（cc，-0.459，=0.005），而ΔFEV则不然（>0.05）。
在接受治疗后进行呼吸困难评估的COPD患者中，IC可作为FEV的有效补充。对于以肺气肿病变为主的COPD患者，IC的增加比FEV更适合解释呼吸困难的缓解。
