Impact Of Inspiratory Muscle Training Based On Passive Expiratory Pressure On Lung Hyperinflation In Patients With Moderate And Severe Chronic Obstructive Pulmonary Disease

Objective(s):The changes of lung hyperinflation and inspiratory fraction(IF)in patients with moderate and severe chronic obstructive pulmonary disease(COPD)after inspiratory muscle intervention were analyzed,aiming to explore the optimization of positive respiratory pressure based approach to the degree of dyspnea caused by traditional inspiratory muscle training(IMT),and explore the mechanism of this intervention to improve lung hyperinflation and inspiratory fraction,so as to provide a new method for inspiratory muscle training in this group.The changes of lung hyperinflation and inspiratory fraction in patients with moderate and severe COPD after inspiratory muscle intervention were analyzed,aiming to explore the optimization of positive respiratory pressure based approach to the degree of dyspnea caused by traditional inspiratory muscle intervention,and explore the mechanism of this intervention to improve lung hyperinflation and inspiratory fraction,so as to provide a new method for inspiratory muscle training in this group.Methods:A single-blind randomized controlled clinical trial design was used in this study.A total of 45 patients with moderate to severe COPD who were admitted to the Department of Rehabilitation Medicine and Respiratory Medicine of the 2nd Hospital Yunnan Province from May 2022 to November 2022 were included.The 45 subjects were divided into PEP-IMT-PEP group(n=15),IMT group(n=15)and PEP group(n=15)by random sequence table.At the same time,age and gender matched healthy people without cardiopulmonary disease and smoking history were recruited from the society to enter the healthy control group(n=10).The subjects were given a single treatment to observe the immediate effects of different modes of inspiratory intervention on lung hyperinflation and inspiratory fraction.In this study,total lung capacity(TLC),residual volume(RV),and inspiratory fraction IF(IC/TLC)were used as the main observation indicators,while Borg dyspnea index and maximum inspiration pressure(MIP)were used as the secondary observation indicators.The PEP-IMT-PEP group and the healthy control group were evaluated before intervention,after PEP treatment in the first group,after IMT treatment and 10 minutes after PEP treatment in the second group,respectively.The IMT group was evaluated at two time points before and after the IMT intervention.The PEP group was evaluated at four time points before intervention,after PEP treatment in the first group,after 30 minutes of rest,and after PEP treatment in the second group.After data collection,intra-and intergroup intervention differences were compared.SPSS 25 was used for statistical analysis,and P≤0.05 was statistically significant.Results:In the experiment,3 patients with moderate and severe COPD were lost to follow-up,and 42 patients with moderate and severe COPD finally completed the experiment.In the PEP-IMT-PEP group,n=15(M=14,F=1,age=64.2±8.3,BMI=21.4±2.19kg/m~2),in the PEP group,n=15(M=13,F=2,age=63.07±7.87,BMI=21.65±2.67kg/m~2),IMT group,n=12(M=12,F=0,age=67.2±6.80,BMI=20.89±2.32kg/m~2),gender ratio of subjects in three groups,There were no statistically significant differences in age or body mass index,and all patients were diagnosed with moderate or severe COPD with comparable baselines.The healthy control group,n=8(M=7,F=1,age=59.1±4.9,BMI=24.19±2.24kg/m2)were healthy people without smoking history and other underlying diseases,and there were no statistical differences in age,gender and BMI between the other three groups of COPD patients.Compared with healthy people,TLC(1.18±0.44L,95%CI 0.32-2.04,P=0.008),RV(2.36±0.43L,95%CI 1.52-3.20,P<0.001)were significantly increased,IF(-0.15±0.31,95%CI-0.21--0.09,P<0.001)was significantly decreased.TLC(-0.25±0.08L,95%CI-0.41---0.09,P=0.003)and RV(-0.21±0.06L,95%CI-0.33--0.09,P=0.001)were significantly decreased after PEP in moderate-severe COPD.TLC(0.32±0.09L,95%CI 0.15-0.49,P=0.001)and RV(0.30±0.09L,95%CI 0.12-0.48,P=0.003)were significantly increased after IMT.There were no significant changes in TLC(-0.06±0.06L,95%CI-0.30-0.17,P=0.568)and RV(0.08,95%CI-0.32-0.48,P=0.679)after PEP-IMT-PEP intervention.TLC difference,RV difference and increased probability of dyspnea before and after intervention were compared between the PEP-IMT-PEP group(n=15)and the IMT group(n=12).TLC difference before and after intervention(difference-0.38,95%CI-0.67--0.09,P=0.01),RV difference(z=-2.245,P=0.025)was significantly decreased,and the increase rate of dyspnea in PEP-IMT-PEP intervention was significantly decreased(P=0.045).Conclusion(s):Traditional inspiratory muscle training(IMT)can significantly increase lung hyperinflation in patients with moderate and severe COPD,while positive expiratory pressure inspiratory muscle training(PEP-IMT-PEP)can significantly relieve lung hyperinflation and dyspnea symptoms in patients with moderate and severe COPD after recovery from traditional IMT,without affecting inspiratory fraction.