肺泡一氧化氮对哮喘患者小气道功能障碍的评估作用

Concentration of alveolar nitric oxide in evaluating small airway dysfunction in asthmatic patients

背景哮喘是一种慢性气道炎症性疾病,炎症涉及近端大气道和外周小气道。50%~60%的哮喘患者存在小气道功能障碍,对小气道功能障碍的评估,在哮喘早期诊断、疾病控制及恶化风险管理方面至关重要。肺泡一氧化氮(concentration of alveolar nitric oxide,CaNO)是外周气道和(或)肺泡区域的小气道炎症指标。目的探讨哮喘患者CaNO对小气道功能障碍的诊断价值及与小气道功能指标的相关关系。方法回顾分析2019年3-11月就诊于解放军总医院第一医学中心呼吸科门诊的哮喘患者55例,依据患者是否有小气道功能障碍,分为小气道功能障碍组和无小气道功能障碍组。对比两组肺功能、CaNO值、呼出气一氧化氮(fractional exhaled nitric oxide,FeNO)值差异。以受试者工作特征曲线(receiver operator characteristic curve,ROC)下面积评估CaNO、FeNO对哮喘患者小气道功能障碍的诊断价值。采用Pearson秩相关分析CaNO与小气道功能指标、FeNO的相关关系。结果小气道功能障碍组25例(男15例,女10例),年龄18~70(44.84±14.34)岁;无小气道功能障碍组30例(男16例,女14例),年龄20~60(38.60±10.68)岁。两组性别、年龄、体质量指数、吸烟史差异无统计学意义(P>0.05)。小气道功能障碍组CaNO、FeNO高于无小气道功能障碍组(P<0.05)。小气道功能障碍组肺功能指标FEV1%pred、FEV1/FVC%、FEF50%pred、FEF75%pred和MMEF%pred均显著低于无小气道功能障碍组(P均<0.05)。CaNO、FeNO两指标单独及联合应用对小气道功能障碍进行诊断时,ROC-AUC(0.95 CI)分别为0.707(0.413~0.984)、0.674(0.364~0.971)、0.787(0.619~0.928)。CaNO与FEF50%pred、FEF75%pred、MMEF%pred呈负相关,与FeNO呈正相关(P<0.05)。结论肺泡一氧化氮对小气道功能障碍有诊断评估价值,最佳截断值为5.70×109 mol/L,但诊断效能都不算太高,作为小气道功能障碍的检测手段尚待商榷。

Background Asthma is a chronic inflammatory disease of the airway,and the inflammation involves the proximal airway and peripheral small airway.More than 50%of patients with asthma have small airway dysfunction,and evaluating small airway dysfunction is crucial in the early diagnosis,disease control and risk management of asthma deterioration.Concentration of alveolar nitric oxide(CaNO)is an indicator of small airway inflammation in the peripheral airway/alveolar area.Objective To investigate the diagnostic value of concentration of alveolar nitric oxide(CaNO)in small airway dysfunction in asthmatic patients and its correlation with small airway function indicator.Methods A total of 55 asthma patients admitted to the Department of Respiratory Medicine of the First Medical Center of Chinese PLA General Hospital from March to November in 2019 were included.According to whether the patients had small airway dysfunction,they were divided into small airway dysfunction group(n=25)and non-small airway dysfunction group(n=30).Lung function,CaNO level and FeNO level were compared between the two groups.The diagnostic value of CaNO and FeNO in small airway dysfunction in asthmatic patients was evaluated by the area under receiver operator characteristic curve(ROC).Pearson correlation test was used to analyze the correlation between CaNO and lung function indicator of small airway and FeNO.Results There were 25 cases(15 males and 10 females)aged(44.84±14.34)years in the small airway dysfunction group and 30 cases(16 males and 14 females)aged(38.60±10.68)years in the non-small airway dysfunction group,and no significant differences in gender,age,body mass index and smoking history were detected between the two groups(all P>0.05).CaNO and FeNO in the small airway dysfunction group were higher than those in the non-small airway dysfunction group(P<0.05,respectively).The lung function indexes,including FEV1%pred,FEV1/FVC%,FEF50%pred,FEF75%pred and MMEF%pred in the small airway dysfunction group were significantly lower than those in the non-small airway dysfunction group(all P<0.05).When CaNO,FeNO used alone or in combination to diagnose small airway dysfunction,the ROC-AUC(95%CI)was 0.707(0.413-0.984),0.674(0.364-0.971)and 0.787(0.619-0.928),respectively.CaNO was negatively correlated with FEF50%pred,FEF75%pred,MMEF%pred,and positively correlated with FeNO(P<0.05).Conclusion CaNO has diagnostic value for small airway dysfunction,and the optimal cut-off value is 5.70×109 mol/L.However,the diagnostic performance is not satisfactory,so it still needs further exploration for its value in detecting small airway dysfunction.