Diagnostic And Predictive Value Of Pulse Forced Concussion Pulmonary Function In Asthma Complicated With Obstructive Sleep Apnea Hypopnea Syndrome

Background:Epidemiological studies have shown that the risk of obstructive sleep apnea hypopnea syndrome(OSAHS)in ordinary asthmatic people is 49.5%,which is 2.7 times higher than that in non-asthmatic patients,and increases with the course and severity of asthma.OSAHS due to upper respiratory tract stenosis,repeated nocturnal hypoxia and other reasons,resulting in airway resistance,airway responsiveness increased,aggravated the condition of asthma and affected the curative effect.The 2020 edition of Chinese guidelines for the Prevention and treatment of bronchial Asthma points out that patients with poorly controlled asthma should be clear about whether they are complicated with OSAHS.However,people’s awareness,consultation rate and treatment rate of OSAHS are low.At present,some medical staff in our country lack knowledge about OSAHS,which leads to a high rate of missed diagnosis of OSAHS.The diagnosis of the disease mainly depends on polysomnography(PSG)or family sleep breathing test(HSAT).The application of Nox-T3 in HSAT diagnosis of OSAHS in Chinese adults has a high success rate and has a good consistency with PSG,but both tests are costly and complicated.Bronchial asthma is mainly characterized by small airway lesions,while OSAHS is characterized by pharyngeal stenosis and upper airway collapse.At present,conventional forced pulmonary ventilation examination can not distinguish the degree of large and small airway stenosis and resistance changes.Pulse forced concussion pulmonary function(IOS)can evaluate the mechanical changes of respiratory system by measuring respiratory resistance,compliance and inertia,and reflect the airway changes of different parts according to different frequency sound waves.In theory,IOS can be used to distinguish simple asthma from asthma complicated with OSAHS.IOS has low requirements for fit,wide range of people,relatively low cost and simple process,and its application value in bronchial asthma,COPD,OSAHS and other obstructive airway diseases has been proved by most studies in recent years.Therefore,this study will analyze the respiratory mechanics characteristics of asthma complicated with OSAHS by IOS examination,screen out the relevant indicators that can identify and warn asthma complicated with OSAHS,and evaluate the predictive value of IOS test in asthma complicated with OSAHS.Purpose:Through IOS examination,to explore the difference of respiratory mechanics between simple asthma and asthma complicated with OSAHS,to screen out the relevant indexes that can identify and warn asthma complicated with OSAHS,and to evaluate the predictive value of IOS examination on asthma complicated with OSAHS.Methods:This study is a single-center cross-sectional study.A total of 116 subjects with diagnosed bronchial asthma were excluded because of poor sleep examination in 8 patients and poor pulmonary function coordination in 5 patients with pulse forced concussion.Finally,the data of 103 subjects were analyzed.According to the results of overnight sleep breathing monitoring(Nox-T3),the patients with sleep apnea hypopnea index(AHI)<5/h were divided into simple asthma group(n=39)and AHI≥5/h group(n=64)with OSAHS.The general clinical data,routine forced pulmonary ventilation parameters,sleep breathing monitoring results(sleep apnea hypopnea index AHI,obstructive apnea index AI,hypopnea index HI,lowest SpO2%and average SpO2%),IOS parameters(respiratory impedance Zrs,respiratory resistance Rrs,respiratory reactance Xrs,reactance area AX and resonance frequency Fres)were collected.To analyze the differences of clinical characteristics and respiratory mechanics between simple asthma and patients with OSAHS,to evaluate the predictive value of IOS in asthma complicated with OSAHS,and to find out the correlation between IOS parameters and OSAHS severity index AHI in asthma patients with OSAHS.Results1.A total of 103 people were included in the study,including 39 patients in the simple asthma group,aged 57.0(25.0)years,accounting for 33.33%of males,and 64 patients in the asthma combined with OSAHS group,aged 62.0(19.25)years old,accounting for 50.00%of the males.The scores of age,neck circumference,BMI and NoSAS in the group with OSAHS were significantly higher than those in the simple asthma group.Among the related indexes of sleep monitoring,the AHI,AI and HI in the group with OSAHS were significantly higher than those in the simple asthma group(P<0.001),and the average SpO2 and the lowest SpO2 were significantly decreased(P<0.001).There was no significant difference in sex,course of asthma,smoking index,number of eosinophils,percentage of eosinophils,ACQ-5 and AQLQ scores between simple asthma group and OSAHS group.The results of routine forced ventilation function:there was no significant difference in FVCpre%,FEV1pre%,FEV1/FVCpre%,MMEF,FEF75%,FEF50%and PD20 between the simple asthma group and the OSAHS group.2.Pulmonary function results of pulse forced concussion:the values of Z5,R5,R10,R20 and R25 in asthma with OSAHS group were significantly higher than those in simple asthma group(P<0.05).There was no significant difference in Fres,ΔR5-R20,X5,X10,X15,X20,X25 and AX between the two groups.Among them,the increase of R20 is independent predictor of OSAHS.3.Multiple stepwise regression analysis was used to construct a predictive model of asthma complicated with OSAHS:age,neck circumference,BMI,NoSAS score,Z5,R5,R10,R20,R25 were analyzed by stepwise regression analysis,and predictive variables were selected.It was found that NoSAS score≥7,R20 could construct the best model to predict the existence of asthma complicated with OSAHS.The predictive probability was ROC curve and AUC=0.770(P<0.001),but age,neck circumference,BMI,Z5,R5,R10 and R25 were not included in the predictive model.Among them,R20(OR=2.768,95%confidence interval 1.502-5.102,P=0.001),NoSAS score≥7(OR=4.579,95%confidence interval 1.805-11.620,P=0.001).4.The best cut-off value of pulmonary function prediction parameters of pulse forced concussion:R20 best cut-off value:0.34kPa/L/s,area under the curve:0.710,sensitivity:54.70%,specificity:74.40%(P<0.001).Conclusion1.Z5,R5,R10,R20 and R25 in the asthma with OSAHS group were significantly higher than those in the simple asthma group.The airway stenosis and remodeling were more obvious in the asthma patients with OSAHS,and the airway resistance increased more obviously.2.R20 elevation in IOS are independent predictors of asthma complicated with OSAHS.The best cut-off values of R20 are:0.34kPa/L/s,(P<0.001).3.The models with NoSAS score≥7,R20>0.34kPa/L/s have good diagnostic and predictive value for asthma complicated with OSAHS.