Correlation of Diaphragm Function Parameters with Pulmonary Function Indicators in COPD Patients and Their Value in Evaluation of Disease Severity

WEI Jie; LIU Jiaoran; PENG Long; ZHOU Meng; ZHANG Rongxin; LIU Huimin; LIN Yu; WANG Tianya; REN Xiangying

doi:10.3969/j.issn.1002-3429.2024.08.009

Abstract：Objective To explore the correlation between diaphragm function parameters and pulmonary function in-dicators in patients with chronic obstructive pulmonary disease(COPD)and their value in evaluation of the severity of the con-dition.Methods We selected 100 patients with COPD admitted from September 2021 to November 2023 as the research sub-jects and included them in the COPD group.According to the grading criteria for COPD,it was further divided into mild to moderate group(COPD grades Ⅰ-Ⅱ)and severe group(COPD grades Ⅲ and above).Another 40 healthy volunteers who were age and gender matched with the COPD group were recruited as the control group.All patients underwent diaphragmatic ultrasound examination[diaphragmatic displacement(DD)and thickness during forced breathing(FRC)and calm breathing(TLC)],as well as pulmonary function examination[forced expiratory volume in one second as a percentage of predicted val-ue(FEV1%pred),forced vital capacity as a percentage of predicted,and forced expiratory volume in one second/forced vital capacity(FEV1/FVC)].The differences in diaphragmatic function parameters between the groups were compared,and the correlation between diaphragmatic function parameters and pulmonary function indicators,as well as their value in evaluating the severity of the condition,was analyzed.Results The modified Medical Research Council(mMRC)scale score of the British Medical Research Association in the COPD group was higher than that in the control group,with FEV1%pred,FVC%pred,and FEV1/FVC were all lower than those in the control group(P＜0.05).The DD and thickness during TLC and TLC-FRC phases were the lowest in the severe group,followed by the mild to moderate group and the control group(P＜0.05).The DD during FRC was higher in the severe group and the mild to moderate group than in the control group(P＜0.05),but there was no statistically significant difference between the severe group and the mild to moderate group(P＞0.05).The DD was positively correlated with FEV1/FVC,FEV1%pred,and FVC%pred in COPD patients(P＜0.01),and the thickness of the diaphragm during TLC was positively correlated with FEV1/FVC and FEV1%pred(P＜0.05).The area under the re-ceiver operating characteristic(ROC)curve(AUC)of DD and diaphragm thickness during TLC for assessing the severity of COPD were 0.821 and 0.673,respectively.Conclusion There is a significant correlation between diaphragmatic function parameters by ultrasound and pulmonary function indicators in COPD patients,and ultrasound detection of diaphragmatic func-tion parameters has important reference value for assisting in evaluating the severity of COPD.