慢性阻塞性肺疾病小气道不同评价方法的相关性研究

The Correlations between Different Evaluation Methods for Small Airways in Chronic Obstructive Pulmonary Disease

目的分析小气道改变在慢性阻塞性肺疾病(简称慢阻肺)中的作用,探讨高分辨率CT(HRCT)和脉冲振荡检查(IOS)在慢阻肺小气道评价中的应用价值。方法选择稳定期慢阻肺患者132例,健康体检对照组43例,行IOS和肺通气功能检查,分析响应频率(Fres)、小气道阻力(R5-R20)与肺通气功能指标相关性。对慢阻肺患者行HRCT检查,测定右肺上叶尖段支气管第3级分支气管壁径线(WT)、伴行肺动脉直径(BWT),并予肺气肿定量(LAA%),分析气道壁增厚、肺气肿与肺通气功能、IOS指标相关性。结果 Fres与第1秒用力呼气容积占预计值百分比(FEV1%pred)、最大呼气中期流量占预计值百分比(FEF25%-75%%pred)、用力呼出50%肺活量的肺流量占预计值百分比(FEF50%%pred)负相关(r=-0.694、-0.561、-0.619,P<0.01);R5-R20与FEV1%pred、FEF25%-75%%pred、FEF50%%pred的r值分别为-0.622、-0.537、-0.560(P<0.01)。受试者工作曲线分析显示Fres和R5-R20曲线下面积较大,诊断慢阻肺的最佳分界点分别为13.93 Hz和0.055 k Pa·L-1·s-1。WT/BWT、LAA%随气流受限加重而增大(F=4.859、9.792,P<0.01);WT/BWT与FEV1%pred负相关(r=-0.329,P<0.05),与Fres、R5-R20正相关(r=0.259、0.241,P<0.05);LAA%与FEV1%pred负相关(r=-0.566,P<0.05),与FEF25%-75%%pred、FEF50%%pred、Fres、R5-R20也存在一定的相关性,r值分别为-0.456、-0.474、0.466、0.340(P<0.05)。结论慢阻肺患者小气道壁增厚,气道阻力增加,其改变程度反映疾病严重程度。HRCT、IOS检查结果与肺通气功能相关,可分别评价小气道结构和功能改变,对慢阻肺的早期诊断、综合评估具有重要意义。

Objective To evaluate the relationship between small airway disease and the progression of chronic obstructive pulmonary disease（ COPD）,and explore the application value of high resolution computed tomography（ HRCT） and impulse oscillometry system（ IOS） in assessing small airways in COPD patients. Methods A total of 132 stable COPD patients and 43 healthy controls volunteered to take the IOS and pulmonary function test. The correlations between resonance frequency（ Fres）,small airway resistance（ R5-R20） and spirometry were analyzed. The patients were also examined by HRCT to measure the thickness of the third generation of apical bronchus of the right upper lobe（ WT）,the adjacent pulmonary artery diameter（ BWT） and the degree of emphysema（ LAA%）. The ratio of WT to BWT（ WT /BWT） was calculated to estimate bronchial wall thickening. Relationships between WT / BWT,emphysema and spirometry,IOS were also studied. Results There were negative correlations between Fres and FEV1% pred,FEF25%-75%% pred,FEF50%% pred（ r =- 0. 694,- 0. 561,- 0. 619,all P〈0. 01）. R5-R20 was negatively associated with FEV1% pred,FEF25%-75%% pred and FEF50%% pred as well（ r =- 0. 622,- 0. 537,- 0. 560,P〈0. 01）. The analysis of receiver operating characteristic curve showed larger areas under the Fres and R5-R20 curves,and the cutoff points to diagnose COPD were 13. 93 Hz and0. 055 k Pa·L- 1·s- 1,respectively. LAA% and WT/BWT increased with airflow limitation（ F = 4. 859,9. 792,both P〈0. 01）. WT / BWT was negatively associated with FEV1% pred（ r =- 0. 329,P〈0. 05）,and positively with Fres and R5-R20（ r = 0. 259,0. 241,P〈0. 05）. LAA% was negatively correlated with FEV1% pred（ r =- 0. 566,P〈0. 05）,and correlations also existed between LAA% and physiological indices of small airways such as FEF25%-75%% pred,FEF50%% pred,Fres and R5-R20（ r =- 0. 456,- 0. 474,0. 466,0. 340,all P〈0. 05）. Conclusions The peripheral airway resistance is increased and bronchial wall thickens in patients with COPD,and these changes can reflect the severity of the disease.Small airway disease measured by HRCT and IOS are related to the spirometric indices,and represent the structural and functional changes of small airways. Combinations of these two tests with spirometry will be possible to make early diagnosis and better control the disease.