Study On The Relationship Between Diaphragm Function And Condition Evaluation In Patients With Chronic Obstructive Pulmonary Disease

Objective 1.To explore the comparison of pulmonary function parameters between sitting and supine position in patients with chronic obstructive pulmonary disease(COPD).2.To explore the changes of diaphragm morphology and function measured by MRI in patients with COPD,and its correlation with the degree of airflow obstruction,COPD assessment test(CAT),6-minute walking distance(6MWD)and the frequency of acute exacerbation of(AECOPD)within one year.Methods 1.Inclusion of subjects:we included 80 COPD patients,including 70 males(87.5%)and 10 females(12.5%),were selected for follow-up in the Department of Respiratory and critical Medicine,affiliated Hospital of NingXia Medical University from October 2017 to December 2018.According to the Global Initiative for chronic obstructive Pulmonary Disease(GOLD),the COPD group was divided into mild-moderate group(COPD-G1 group,n=41)and severe-extremely severe group(COPD-G2 group,n=39).21 healthy adults were selected in the control group,including 13 males(62%)and 8 females(38%).All subjects were collected,including sex,age and body mass index(BMI)and smoking index(SI).2.Clinical study of subjects:(1)all COPD patients were included in the electronic management platform-mobile APP(COPD butler),daily discomfort symptoms,COPD assessment test(CAT)and peak expiratory flow(PEF)were were monitored by COPD.Based on mobile APP(COPD butler)daily record: daily discomfort symptoms,COPD,CAT,walking test.The discomfort symptoms,CAT and PEF values of COPD patients weredynamically monitored within one year,and the frequency of AECOPD within one year was defined by acute exacerbation(AECOPD);(2)COPD patients complete the 6-minute walk test(6MWT);(3)All subjects were tested for pulmonary function in sitting and supine position;(4)All subjects were measured the following parameters: morphology of diaphragm(eD/L),mobility of diaphragm(DM),and paradoxical movement of diaphragm(MP).To compare the pulmonary function parameters of sitting and supine position in patients with COPD,and the changes of diaphragm morphology and function in patients with COPD were observed by MRI diaphragm scan,and the relationship between diaphragm and pulmonary function,CAT,6-minute walking distance(6MWD)and AECOPD.Results 1.Comparison of pulmonary function between sitting and supine position in healthy control group: measurements of FEV1/ FVC% was significant difference(t=4.347,P<0.05)between sitting(87.37±10.63)and supine(76.49±7.22)position,FEV1/ FVC% was higher in the sitting position compared to supine,there was no significant difference in FEV1,FVC and FEV1/% between sitting and supine position;comparison of pulmonary function between sitting and supine position in COPD group: there was significant difference(all P<0.05)in FEV1,FEV1/FVC%,FEV1/pre% between sitting and supine position.FEV1,FEV1/FVC%,FEV1/pre% was higher in the sitting(1.63±0.75;54.73±12.62;53.71±22.71)comparedtosupineposition(1.52±0.69;50.00±15.22;51.38±21.50).2.Comparison of diaphragm morphology and function between healthy control group and COPD group: there was no significant difference in the morphology and mobility of the left and right diaphragm in the healthy group,but there was significant difference(t=-2.371,P<0.05)in the paradoxical movement of the diaphragm between the left side(69.63 ±22.06)and the right side(78.53 ±24.93),right hemidiaphragm has less paradoxical movement than left hemidiaphragm.In COPD groups,there was significantdifference(t=-4.468,P<0.001)in the paradoxical movement of the diaphragm between the left side(67.00±23.44)and the right side(74.76±26.11).,right hemidiaphragm has less paradoxical movement than left hemidiaphragm.Also there was no significant difference in the morphology and mobility of the left and right diaphragm;the morphology of diaphragm in COPD group was flatter than that in healthy control group,and the difference was statistically significant(Z=-2.381 P<0.05).There was no significant difference in mobility and paradoxical movement of the diaphragm between the two groups;compared with the control group and the subgroups of COPD with different severity of airflow obstruction,there was significant difference between G1 group(1.29±0.12)and the control group(z =-2.209,P <0.05)in the morphology of the diaphragm.The morphology of G1 group was more flatter than that of the control group.there was no significant difference between the G1 group and the control group in diaphragm mobility and paradoxical movement;there were significant differences between G2 group and healthy control group(P < 0.05)in the diaphragmatic morphology,mobility and paradoxical movement(1.20 ± 0.07;56.65 ± 10.57;56.17 ± 16.84),the morphology of diaphragm in COPD patients with severe to very severe disease became more flatter,the activity of diaphragm decreased and there was significant paradoxical movement than control group.3.Comparison of morphology and function of diaphragm in different subgroups of COPD: there were significant differences(Z=-2.546,P<0.05;t=5.602,P<0.001;t=6.696,P<0.001)between G1 group and G2 group in the diaphragmatic morphology,mobility and paradoxical movement.The more severe the pulmonary function of patients with COPD,the more significant the morphological changes of diaphragm,the smaller the mobility and the more significant paradoxical movement of the diaphragm.4.The correlation between the morphology and function of diaphragm and pulmonary function in COPD group: there was a positive correlation between the morphology ofdiaphragm and pulmonary function FEV1,FVC,FEV1/% in COPD group(P<0.05),there was no correlation with FEV1/FVC%;there was a significant positive correlation between diaphragm mobility and pulmonary function FEV1,FVC,FEV1/pre%,FEV1/ FVC% in COPD group(P<0.001);there was a significant positive correlation between diaphragm paradoxical movement and pulmonary function FEV1,FVC,FEV1/pre%,FEV1/ FVC% in COPD group(P<0.001).5.The correlation between different diaphragm morphology subgroups and clinical evaluation parameters in COPD group: according to the lower limit of 95% confidence interval(95%CI)of diaphragm morphology(1.28mm)as the threshold,the COPD group was divided into normal diaphragm morphology group(S1 group)and diaphragm morphology abnormality group(S2 group).The results showed that there was a significant difference in pulmonary function FEV1 between S1 group(2.09 ±1.06)and S2 group(1.48 ±0.71)(t =2.091,P<0.05);there was significant difference(Z=-1.974 P<0.05)in the frequency of acute exacerbation within one year between S1 group(1.83 ±1.44)and S2 group(2.45 ±1.33),the frequency of acute exacerbation in S2 group was higher than that in S1 group.There was no significant difference in pulmonary function FVC,FEV1/pre%,FEV1/ FVC%,CAT score and6 MWD between the two groups.Conclusion 1.The result of pulmonary function test in supine position is lower than that in sitting position,which can lead to underestimation and overdiagnosis of COPD.Supine position is not recommended as the standard position for lung function test.2.There is diaphragm dysfunction in patients with COPD,and the diaphragm dysfunction is positively correlated with the degree of airflow obstruction.3.The morphology of diaphragm in patients with COPD is related to the frequency of acute exacerbation.The more the frequency of acute exacerbation is in patients with abnormal diaphragm,it is recommended as a predictor of acute exacerbation of COPD.