Pulmonary diffusing capacity testing is widely used in clinical practice for assisting in the diagnosis and quantitative evaluation of interstitial lung diseases, differentiating emphysema, and assessing whether other pulmonary diseases are complicated with pulmonary diffusing capacity impairment, among other applications. In recent years, several new domestic pulmonary diffusing capacity testing instruments have been successively developed, registered and launched on the market; however, their reliability in clinical use remains to be verified.

To evaluate the clinical reliability of the pulmonary diffusing capacity measurement results obtained by the new domestic MeHow MeAir 9000.

From June 15 to September 1, 2023, among patients who underwent examinations in the Pulmonary Function Laboratory of the First Affiliated Hospital of Guangzhou Medical University, 68 subjects with clinically diagnosed chronic obstructive pulmonary disease (COPD) and 68 with interstitial lung disease (ILD) were randomly selected, and divided into the ILD group and the COPD group. A cross-over design was adopted, where the subjects were randomly assigned to use two types of pulmonary diffusing capacity testing instruments in sequence: the experimental group (MeHow MeAir 9000) and the control group (Jaeger MasterScreen Diffusion). Professional pulmonary function examiners performed pulmonary diffusing capacity and vital capacity tests on the subjects in accordance with the procedural and quality control standards specified in the standards for single-breath carbon monoxide uptake in the lung guideline issued by the European Respiratory Society/American Thoracic Society (ERS/ATS). The collected indicators included: diffusing capacity of the lung for carbon monoxide (DLCO), inspiratory vital capacity (IVC), alveolar ventilation (VA), ratio of diffusing capacity of the lung for carbon monoxide to alveolar ventilation (DLCO/VA), forced vital capacity (FVC), forced expired volume in one second (FEV₁), and percentage of predicted diffusing capacity of the lung for carbon monoxide (DLCO%pred). Consistency analysis was conducted on the measurement results obtained by the two groups of instruments and the results of the grading of pulmonary diffusing capacity impairment severity.

Statistical analysis and comparison of the consistency of measurement values of DLCO, IVC, VA, DLCO/VA, FVC, and FEV₁ between the two instruments: in the interstitial lung disease group, the ICCs were 0.981 6, 0.944 9, 0.916 8, 0.969 8, 0.984 4, and 0.982 4 respectively; in the COPD group, the ICCs were 0.990 7, 0.917 9, 0.920 9, 0.960 2, 0.979 8, and 0.989 7 respectively. The analysis results of both disease groups showed high consistency, and the results were statistically significant (P< 0.05). In the Bland-Altman scatter plots of the measurement values of DLCO, IVC, VA, DLCO/VA, FVC, and FEV₁ from the two instruments, the proportions of data points falling within the 95% confidence interval (95%CI) in the interstitial lung disease group were 95.5%, 94.0%, 94.0%, 95.5%, 92.5% and 94.0% respectively; in the COPD group, the proportions were 92.4%, 93.9%, 93.9%, 95.5%, 97.0% and 95.5% respectively. These results indicated that the consistency of diffusing capacity measurement values between the experimental group instrument and the control group instrument was good. In terms of the comparison of the two instruments regarding the grading of diffusing capacity impairment (classified into 4 grades: normal, mild, moderate, and severe based on DLCO%pred) in both disease groups, the ICCs in the interstitial lung disease group and the COPD group were 0.939 7 and 0.975 0 respectively, with statistically significant results (P< 0.05). The weighted kappa values from Cohen's weighted kappa test for consistency strength were 0.896 9 and 0.837 2 respectively, and the analysis results were statistically significant (P< 0.05), suggesting that the experimental group instrument and the control group instrument have good consistency in evaluating the grading of pulmonary diffusing capacity impairment.

The pulmonary diffusing capacity testing of the new domestic MeHow MeAir 9000 shows high measurement accuracy in chronic respiratory diseases and good reliability in evaluating the severity of pulmonary diffusing capacity impairment, making it suitable for clinical promotion and application.

肺弥散功能检查在临床广泛应用于辅助诊断和定量评价间质性肺疾病（间质肺病）、鉴别肺气肿、评估其他肺部疾病是否合并肺弥散功能障碍等。近几年，一些新型的国产肺弥散功能测试仪器陆续开发和注册上市，但其临床使用可靠性仍有待验证。

评价国产新型MeHow MeAir 9000肺功能仪的肺弥散功能测量结果在临床使用中的可靠性。

2023-06-15—09-01在广州医科大学附属第一医院肺功能室检查患者中，随机选取临床诊断为慢性阻塞性肺疾病（慢阻肺病）和间质肺病的受试者各68例，分为间质肺病组和慢阻肺病组。采用交叉设计方法，让受试者随机分别使用实验组（MeHow MeAir 9000肺功能仪）和对照组（Jaeger MasterScreen Diffusion肺功能仪）两种肺弥散功能测试仪器，由肺功能检查专业人员按照2017欧洲呼吸协会/美国胸科协会（ERS/ATS）的《2017 ERS/ATS肺弥散功能检查技术标准》指南流程和质控标准对受试者进行肺弥散功能、肺活量检查，采集指标包括：一氧化碳弥散量（DLCO）、吸气量（IVC）、肺泡通气量（VA）、一氧化碳弥散量与肺泡通气量比值（DLCO/VA）、用力呼气肺活量（FVC）、第一秒用力呼气肺活量（FEV₁）、一氧化碳弥散量占预计值百分比（DLCO%pred），并对两组仪器所得的测量值及肺弥散功能障碍程度分级两方面的结果进行一致性分析。

两组仪器的DLCO、IVC、VA、DLCO/VA、FVC、FEV₁测量值一致性统计分析对比：间质肺病组的组内相关系数（ICC）分别为0.981 6、0.944 9、0.916 8、0.969 8、0.984 4、0.982 4，慢阻肺病组的ICC分别为0.990 7、0.917 9、0.920 9、0.960 2、0.979 8、0.989 7，两组分析结果显示一致性较高，差异有统计学意义（P<0.05）；两组仪器的DLCO、IVC、VA、DLCO/VA、FVC、FEV₁测量值的Bland-Altman散点图中，间质肺病组落在95%CI之内的数据点比例分别为95.5%、94.0%、94.0%、95.5%、92.5%、94.0%，慢阻肺病组落在95%CI之内的数据点比例分别为：92.4%、93.9%、93.9%、95.5%、97.0%、95.5%，提示实验组与对照组仪器的弥散功能测量值一致性佳。在两组仪器关于两组疾病的弥散障碍程度分级（按DLCO%pred分为正常、轻度、中度和重度4个等级）对比方面，间质肺病组和慢阻肺病组的ICC分别为0.939 7、0.975 0，分析结果有统计学意义（P<0.05）；Cohen's加权kappa一致性强度检验的加权kappa值分别为：0.896 9、0.837 2，分析结果有统计学意义（P<0.05），提示实验组与对照组仪器在评估肺弥散功能障碍程度分级方面一致性良好。

国产新型MeHow MeAir 9000肺功能仪的肺弥散功能检查在慢性呼吸道疾病方面的测量准确度高，评价肺弥散功能障碍程度的可靠性佳，适于临床推广使用。