Ultrasound Assessment Of The Morphology Alternation Of The Diaphragm In Chronic Obstructive Pulmonary Disease: Relationships With Pulmonary Function And The BODE Index

Objective To evaluate alterations of diaphragm morphology and its correlation with pulmonary function and BODE index in COPD patients.Methods 80 subjects with COPD(64 males)recruited from the Shanghai East Hospital of Tongji University and 60 aged-matched control subjects(50 males)were included in the present study from May 2015 to August 2016.The age of them ranged from 44 to 87 years old.They were divided into mild(n=17),moderate(n=21),severe(n=24),very severe(n=18).Those who met the enrollment criteria underwent 1)pulmonary function test;2)echographic assessment of diaphragmatic mobility during quiet and deep breathing,thickness at functional residual capacity(FRC)and total lung capacity(TLC),and thickening fraction(from FRC to TLC);3)Body mass index(BMI),6-minute walk test(6mwt),dyspnea(m MRC);4)Calculating the BODE index basing on above indexes.Results Compared with the healthy subjects,diaphragm mobility significantly decreased in COPD during quiet and deep breathing(1.75±0.67 vs.2.07±0.32,t=3.61;4.16±0.98 vs.5.17±0.76,t=6.82.respectively,all P<0.05),more obviously occurred during deep breathing(24.3%).Diaphragm thickness was significantly lower than healthy subjects at FRC and TLC(0.18±0.04 vs.0.20±0.04,t=3.07;0.41±0.14 vs.0.50±0.09,t=4.70.respectively,all P<0.05),more pronounced occurred at TLC(22%);similarly,thickening fraction also significantly decreased(1.19±0.28 vs.1.50±0.26,t=6.48,P<0.05).Among COPD subgroups during deep inspiration,diaphragm ultrasound parameter was gradually decreased with increasing of airway obstruction,which shown significantly differences in moderate subgroup compared with healthy subjects(13.3% ― 22%,all P<0.05),more obviously occurred in severe and very severe one(24%―42%,all P<0.05).The diaphragm morphology presented a linear positive with FEV1(r=0.522―0.693,all P<0.05),MVV(r=0.380―0.485,all P<0.05),TLC(r=0.334―0.448,P<0.05)and negative correlation with 6mwt(r=0.505―0.536,all P<0.05),dyspnea(r=﹣0.480―﹣0.586,all P<0.05)and BODE index(r=﹣0.437―﹣0.583,all P<0.05).COPD patients were divided into two subgroups based on the degree of diaphragmatic thickening fraction: G1(≤1.43),G2(>1.43).The G1 presented with lower diaphragm mobility and thickness during deep inspiration compared with the G2 subjects(4.07±0.95 vs.4.64±0.97,t=1.97;0.39±0.15 vs.0.48±0.09,t=2.12.respectively,all P<0.05).The G1 subjects presented poorer 6MWT and greater dyspnea,BODE index when compared with the G2 patients(6mwt 490.15±123.97 vs.577.86±146.19,t=2.33;dyspnea 3.45±1.24 vs.2.29±0.99,t=﹣3.30;BODE 4.23±2.68 vs.2.50±1.56,t=﹣4.20.respectively,all P<0.05).The G1 subjects also presented lower airway obstruction(FEV1 47.87±23.13 vs.76.21±20.19,t=4.25,P<0.05)and maximal voluntary ventilation(MVV 43.89±17.14 vs.60.76±19.01,t=3.28,P<0.05)than did the G2 patients.Conclusions Ultrasound could indirect quantitative evaluating diaphragm muscle function.The diaphragm mobility and thickness decreased in the patients with COPD,more pronounced occurred during deep inspiration.The diaphragm morphology could be parameters to reflect the severity of the disease and alteration of BODE index.The combination of diaphragm ultrasound and BODE index could be helpful to early diagnose diaphragm dysfunction.