目的： 观察稳定期Ⅱ、Ⅲ级慢性阻塞性肺疾病（chronic obstructive pulmonary disease, COPD）患者的气道阻力（airway resistance, R_aw）与呼出气流受限的关系。方法： 将102例稳定期COPD患者根据中华医学会呼吸病学会制订的诊断标准分为Ⅱ级（53例）和Ⅲ级（49例）2组,2组患者在检测前8 h内均未应用支气管舒张剂,并在吸入沙丁胺醇400 μg后接受常规肺功能和气道阻力测试。另选择同期的28名成年健康体检者作为对照组。结果： Ⅲ级COPD患者的第一秒用力呼气容积（forced expiratory volume in one second, FEV₁）、呼气峰流量（peak expiratory flow, PEF）及用力呼出50%肺活量时流量（forced expiratory flow at 50% forced vital capacity, FEF₅₀）均显著低于Ⅱ级COPD患者,而2组患者的总气道阻力（total airway resistance, R_tot）、有效气道阻力（effective resistance, R_eff）、吸气阻力和呼气阻力（inspiratory resistance/expiratory resistance,R_insp/R_exp）均较对照组受试者显著增高。49例Ⅲ级COPD患者中吸气分数[深吸气量（inspiratory capacity, IC）/肺总量（total lung capacity, TLC)]≤25%者有7例（14.3%）,而53例Ⅱ级COPD患者中仅有1例的IC/TLC≤25%（1.9%）。COPD患者的R_tot明显高于R_eff,R_exp与FEV₁、PEF、FEF₅₀间的相关性最为密切（r均>0.80,P均<0.01）;R_insp与各项肺功能参数间的相关性稍弱,但也均有统计学意义（P<0.01）。结论： 稳定期Ⅱ、Ⅲ级COPD患者已存在较严重的气流受限,Ⅲ级COPD患者呼气阻力明显增高,且以外周气道阻力成分增高为主要因素,并更易出现呼吸困难症状。

Objective: To study the correlation between airway resistance (R_aw) and expiratory flow limitation (EFL) in patients with chronic obstructive pulmonary disease (COPD). Methods: One hundred and two stable Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages Ⅱ-Ⅲ COPD patients, of them 53 were stage Ⅱ and 49 were stage Ⅲ, were enrolled. Patients were not taking bronchodilator eight hours before examination, then lung function testing and respiratory airway resistance were measured after salbutamol (400 μg) inhalation. Twenty eight healthy subjects were served as controls. Results: The peak expiratory flow (PEF), peak expiratory flow (PEF) and forced expiratory flow at 50% forced vital capacity (FEF₅₀) in stage Ⅲ COPD patients were significantly lower than those in stage Ⅱ COPD patients. Seven (14.3%) patients with stage Ⅲ COPD and only 1 (1.9%) patients with stage Ⅱ COPD revealed inspiratory fraction [ratio of inspiratory capacity and total lung capacity (IC/TLC)] ≤25%. The total airway resistance (R_tot), effective airway resistance (R_eff), inspiratory airway resistance/expiratory airway resistance (R_insp/R_exp) of the two COPD groups were significantly higher than those of the control group. The R_exp of COPD patients had the best correlation with FEV₁, PEF and FEF₅₀ (all r>0.80, P<0.01). Conclusions: R_aw especially R_exp is already obviously increased in stable moderate to severe COPD patients on account of the severe expiratory flow limitation. Peripheral component of air way resistance might be the main factor of the increment. The symptom of dyspnea would be prone to appear with the deterioration of lung function.