Analysis Of Characteristics Of Clinical Features And Pulmonary Function Of Preserved Ratio Impaired Spirometry

Objective:To analysis the characteristics of clinical features and pulmonary function of PRISm patients by comparing PRISm group,COPD group and control group.Methods:In this study,patients met including and exclusion criteria admitted from August 2021to December 2022 were collected.According to the bronchodilator test,patients were divided into three groups:control group（FEV₁/FVC≥70%,FEV₁%pred≥80%）,PRISm group（FEV₁/FVC≥70%,FEV₁%pred and/or FVC%pred<80%）,COPD group（FEV₁/FVC<70%）.50 cases were collected in each group.Clinical characteristics（including sex,age,body mass index,smoking history,current smoking,hypertension,diabetes,coronary disease,clinical symptoms,m MRC,blood routine test,chest CT）,and pulmonary function indexes（including ventilatory function,lung volume,diffusion function,impulse oscillometry）were compared among the three groups,to analyze the characteristics of clinical features and pulmonary function of PRISm patients.Results:1.Compared with COPD group,PRISm group had higher BMI,Lower Smoking Index,m MRC,dyspnea and less emphysema on chest CT（P<0.05）.Compared with control group,PRISm group had lower percentage of eosinophils and lymphocyte to neutrophil ratio（P<0.05）.Compared with COPD group and control group,the hemoglobin of PRISm group was the lowest（P<0.05）.There were no significant differences in sex ratio,current smoking status and complication among the three groups（P>0.05）,but the analysis of age bracket showed that 50%of the COPD patients were between 60-69 years old,than the other two groups.2.Compared with control group,FEV₁ and FEV₁%pred after bronchodilator inhalation was lower in PRISm group（P<0.05）.Compared with COPD group,the FEV₁/FVC and FEV₁/VC after bronchodilator inhalation was higher in PRISm group（P<0.05）.Compared with the control group and COPD group,FVC and FVC%pred in PRISm group were the lowest after bronchodilator inhalation（P<0.05）.PEF%pred,MEF_75/25%pred,MEF _50%pred,MEF _25%pred in PRISm group were higher than COPD group and lower than control group（P<0.05）.3.Compared with control group,PRISm group had lower D_LCO%pred,IC%pred（P<0.05）.Compared with COPD group,PRISm group had higher D_LCO/VA%pred,lower RV%pred and FRC/TLC（P<0.05）.Compared with COPD group and control group,VC%pred,TLC%pred and FRC%pred of PRISm group were the lowest（P<0.05）.RV/TLC in PRISm group was higher than control group and lower than COPD group（P<0.05）.4.Compared with the control group,R5%pred,R10%pred,R5-20,Z5%pred,Fres,AX were higher in PRISm group（P<0.05）.There was no significant difference in R20%pred among the three groups（P>0.05）.5.BMI index was positive correlated with FEV₁/FVC and FEV₁%pred after bronchodilator inhalation.The higher BMI index,the higher FEV₁/FVC and FEV₁%pred（r=0.195、0.192）.6.The FVC improvement rate and FEV₁ improvement rate were positive correlated with m MRC,The higher FVC improvement rate and FEV₁ improvement rate,the higher m MRC,the more severe the dyspnea（r=0.278、0.247）.Conclusions:1.Small airway dysfunction can occur in PRISm without significant airflow obstrucion similar to that seen in COPD patients.2.The lung volume of PRISm patients may decrease.3.The diffusion function of PRISm patients may decrease.