Analysis Of Functional Residual Capacity And Related Factors In OSAHS And OS Patients

Objective:To observe the effects of functional residual volume?FRC?changes on obstructive sleep apnea hypopnea syndrome?OSAHS?and overlap syndrome?OS?,and to clarify the role of static lung volume change in OSAHS and OS,as well as in its diagnosis and severity assessment.Method:1.Selecting the patients with diagnosed OSAHS by night polysomnography?PSG?.All patients were screened for OSAHS and OS after daytime sitting lung function examination.Some patients were excluded from medical history collection and the examination of height and weight,such as the obese patients with BMI>30kg/m2,the patients with asthma,emphysema,pulmonary heart disease,restrictive pulmonary disease,pulmonary embolism,pulmonary surgery,pulmonary tumors and other serious diseases,such as heart,lung,liver and kidney dysfunction.A total of 256patients with OSAHS and 45 patients with OS were selected finally.2.According to FRC%pred divided OSAHS patients group into three groups:?80%,80%-110%,and>110%.Comparing the difference of the sleep hypopnea index such as?AHI?the arousal index?ArI?.Oxygen reduction index?ODI?,total sleep time?TST?,maximum apnea time?MAT?,mean apnea time?AAT?,mean oxygen saturation?MSaO2?,minimum oxygen saturation?LSaO2?,blood Sleep-related indicators such as oxygen saturation below 90%of the total recorded time?TP90%?in groups.To exclude age,gender,BMI and other factors affecting PSG monitoring indicators,Pearson partial correlation test was used to correct age,gender,and BMI for correlation analysis and analyzing the correlation between FRC%pred and PSG monitoring indicators AHI,ArI,ODI,TST,MAT,Correlation of AAT,MSaO2,LSaO2,TP90%,etc.3.The OS group patients were classified according to the first second forced expiratory volume FEV1%>50%classified as COPD light and moderate group?GOLD1,2 level?and<50%classified as COPD heavy and extremely severe group?GOLD3,4?,Analyzing the lung volume related indicators such as residual gas volume?RV?,functional residual capacity?FRC?,total lung volume?TLC?and PSG monitoring indicators AHI,ArI,ODI,TST,MAT,AAT,MSaO2,LSaO2,TP90%whether exist differences between these two groups.4.Applying the Propensity Score Matching?PSM?method to data of OSAHS group and the OS group 301 group.using 45 OS groups as the case group,256 OSAHS groups as the control group.Gender,age and BMI were used as matching variables,and matching tolerance was 0.01,applying the two sets of data were matched by 1:1.Analyzing the differences between the new data sets in the lung volume index RV,FRC,TLC and other PSG monitoring indicators AHI,ArI,ODI,TST,MAT,AAT,MSaO2,LSaO2,TP90%,etc.Result:1.In the case of similar gender,age,BMI,etc?no significant difference between groups?,the variation of FRC%pred was statistically different among AHI,ArI,ODI,MSaO2,LSaO2,and TP90%?P<0.05?,but there was no statistically significant difference in TST,MAT,AAT?P>0.05?.Pearson partial correlation test was used to analyze the correlation between FRC%perd and PSG monitoring indicators after adjusting for age,sex and BMI.It was observed that with the increase of FRC%pred,AHI,ArI,ODI and TP90%decreased,that is,FRC%PRED was negatively correlated with AHI,ArI,ODI and TP90%?P<0.05?.MSaO₂ and LSaO₂ showed an upward trend,that is FRC%pred was positively correlated with MSaO₂ and LSaO₂?P<0.05?.2.In the case of similar gender,age,and BMI?no statistically significant difference between the groups?,there were significant differences in TLC%pred,AAT and MSaO₂ between severe COPD group and mild and moderate COPD group?P<0.05?,but the heavier COPD,the smaller TLC%pred,the lower AAT and MSaO2.However,there were no significant differences in RV%pred,FRC%pred,AHI,ArI,TST,MAT,LSaO₂,TP90%and other sleep related indicators?P>0.05?.3.After 1:1 matching of Propensity score matching?PSM?,the factors affecting OSAHS and OS such as sex,age and BMI were equally comparable between the two groups.The observation results showed that the static lung volume of OS group was larger than that of OSAHS group alone.The RV,FRC,RV%pred,FRC%pred and TLC%pred of OS group had statistical differences between the two groups?P<0.05?,and the severity of OSAHS in OS group was higher than that in OSAHS group alone.Compared with OSAHS alone,the AHI and ODI were lower,LSaO₂%and TP90%were higher,and there were significant differences between the two groups?P<0.05?.Other sleep-related indicators,such as ArI,TST,MAT and AAT,were lower in OS group than in OSAHS group,but there was no significant difference between the two groups?P>0.05?.Conclusion:1.The increase of static lung volume FRC can improve the severity of OSAHS.With the increase of FRC,the AHI,ArI,ODI and TP90%of OSAHS patients decreased,while MSaO 2 and LSaO 2 increased.This may be related to the increase of lung volume FRC,which can increase the stability of upper airway and improve the collapse of upper airway.2.In OS patients,the more severe COPD is,the heavier the airflow restriction is,and the larger the lung volume is and the static lung volume RV,FRC,TLC should be increased.However,the more severe the airflow restriction is,the higher the corresponding OSA prevalence rate is.This study can not match the OSA prevalence and severity of COPD groups to different degrees.Therefore,there is controversy about the impact of different degrees of COPD on OSAHS in OS,and more experimental studies may be needed to confirm the results.3.The static lung volume RV,FRC and TLC of OS patients were increased compared with those of OSAHS patients,while the increase of lung volume could reduce the prevalence of OSA.AHI and ODI of OS patients were lower than those of OSAHS patients,while the LSaO₂%and TP90%were higher than those of OSAHS patients.The increase of lung volume has a potential hypoxic protective effect on OSAHS in OS.