| Background Mycoplasma pneumoniae is the common pathogen of community-acquired pneumonia in school-age children.Mycoplasma pneumoniae infection is closely related with asthma,it can induce asthma in children without asthma symptoms or aggravate the symptoms of asthma.The pulmonary function is widely used in the field of children’s respiratory systemis,helpful to assess the lung function damage and the severity of the disease in children with community-acquired pneumonia,and is of great significance for tracking the recovery of the pulmonary function damage and the clinical prognosis of pneumonia.At present,there are few studies on the characteristics of conventional ventilation and impulse oscillometry,airway responsiveness and follow-up of asthma in children with Mycoplasma pneumoniae pneumonia.Objective To analyze the pulmonary function characteristics and follow-up results of children with lobar Mycoplasma pneumoniae pneumonia in 5-14 years old,and to explore the early predictive value of pulmonary function tests in children with asthma-related symptoms after Mycoplasma pneumoniae pneumonia.Methods Collect children with Mycoplasma pneumoniae pneumonia aged 5-14 years old who were hospitalized in the Pediatric Respiratory Department of Shandong Provincial Hospital from January 2018 to December 2019,showed segmental or lobar pneumonia on chest imaging.The children have been excluded from asthma,allergic rhinitis and other diseases that affect pulmonary function.During the hospitalization,they have completed conventional ventilation,impulse oscillometry,and bronchodilation tests in a stable condition and well-coordinated.Six months after discharge from the hospital,children who completed the bronchodilation test were followed up with a telephone questionnaire on asthma-related symptoms.The results of pulmonary function tests and asthma-related symptoms in children with Mycoplasma pneumoniae pneumonia were retrospectively analyzed.Results 1.A total of 155 children with Mycoplasma pneumoniae pneumonia were included.155 cases completed conventional ventilation,120 cases completed impulse oscillometry,105 cases completed bronchodilation tests with conventional ventilation and impulse oscillometry methods,The pulmonary function examination time is 5(2,8)days after admission.2.155 cases conventional ventilation pulmonary function tests showed that 40 cases(25.8%)with normal ventilation function,115 cases(74.2%)with ventilation dysfunction,mainly decreased in vital capacity and small airway function indexes,79 cases(51.0%)with vital capacity(VC)less than 80%of expected value:Among forced expiratory flow at 50%vital capacity(FEF50%),forced expiratory flow at 25%vital capacity(FEF75%),maximum midexpiratory flow(MMEF),2 or more of the 3 items were lower than 65%predicted value in 82 cases(52.9%).Excluding gender,height and weight influence,5-8 years old children with Mycoplasma pneumoniae pneumonia forced vital capacity(FVC),forced expiratory volume in one second(FEV1),peak expiratory flow(PEF)were significantly decreased than healthy children of the same age.3.120 cases impulse oscillometry pulmonary function test showed normal airway resistance in 106 cases(88.3%),increased airway resistance in 14 cases(11.7%),and total airway resistance(R5)increased in 6 cases,central airway resistance(R20)increased in 4 cases,and peripheral elastic resistance(X5)increased in 4 cases.4.Correlation analysis among 120 cases impulse oscillometry and conventional ventilation pulmonary function indexes,impulse oscillometry airway resistance index total respiratory impedance(Z5),R5,X5 and conventional ventilation index forced expiratory flow at 75%vital capacity(FEF25%),FEF50%,FEF75%,MMEF.The correlation coefficient(r),between Z5 and FEF25%was-0.325,that between R5 and FEF25%was-0.305,that between X5 and FEF25%,FEF50%,FEF75%or MMEF was-0.309,-0.379,-0.338,-0.352 respectively,there was a good negative correlation,P<0.01.5.105 cases bronchodilation test checked the pulmonary function,after 15 minutes of inhalation of fast-acting bronchodilator(Terbutaline Sulfate Atomized Liquid),such as expiratory flow index FEV1,PEF,FEF25%,FEF50%,FEF75%,MMEF,increased significantly,and airway resistance indexes of Z5,R5,R20,X5 were significantly reduced,the difference before and after inhalation was statistically significant(P<0.01);FEV1 improvement rate≥12%,MMEF improvement rate≥25%were 11 cases(10.5%),29 cases(27.6%)respectively,Reduction rate of R5≥20%,X5≥30%were 27 cases(25.7%),28 cases(26.7%)separately.6.Asthma-related symptoms telephone questionnaire was performed in 105 children that finished bronchodilation test,88 cases were completed follow-up,with the follow-up rate 83.8%(88/105),17 cases were lost to follow-up,and the median follow-up time was 13 months(6-28 months).After discharge from the hospital,18 children suffered from at least one of wheezing,repeated coughing or chest tightness,repeated respiratory infections,the incidence was 20.5%(18/88).Asthma-related symptom-positive group had increased indexes than those of the asthma-related symptom-negative group in FEV1 improvement rate≥12%,the MMEF improvement rate≥25%,and the R5 reduction rate≥20%,such as FEV1 improvement rate≥12%was different brtween the two groups(χ2=8.275,P=0.004);the rate of X5 reduction≥30%in the asthma-related symptom-positive group was less than that in the asthma-related symptom-negative group,and the difference had no statistically significant(χ2=0.525,P=0.469).7.115 children with conventional ventilation dysfunction were reexamined in 23 cases,the review time is 2 weeks to 24 months,10 cases had normal ventilatory function,8 cases had small airway dysfunction,4 cases had obstructive ventilatory dysfunction,and 1 case had restrictive ventilatory dysfunction.FEV1,PEF,FEF25%,FEF50%were significantly increased than before,and the difference was statistically significant(P<0.05),and FEF75%and MMEF were not significantly different from the previous test.14 children with elevated airway resistance were re-examined in 5 cases,the review time is 2 weeks to 2 months,4 cases had normal airway resistance,and 1 case still had increased peripheral elastic resistance.Six children with FEV1 improvement rate≥12%were re-examined in 11 cases,the review time is 2 weeks to 22 months,5 cases had negative bronchodilation test,the FEV1 improvement rate were 4.7%,-1.9%,9.7%,-3.2%,6.1%separately,and 1 case had positive bronchodilation test,FEV1 improvement rate was 14%.Conclusion 1.The conventional ventilation pulmonary function of children with lobar Mycoplasma pneumoniae pneumonia between 5-14 years old is dominated by restrictive ventilation dysfunction.The small airway function indexes are significantly damaged and recover slowly than the larger airway function indexes.2.A small number of children with lobar Mycoplasma pneumoniae pneumonia have increased airway resistance.Part of impulse oscillometry airway resistance index have a good negative correlation with the expiratory flow index of conventional ventilation.3.Children with lobar Mycoplasma pneumoniae pneumonia have reduced airway resistance and improved lung ventilation after inhalation of fast-acting bronchodilator.The pulmonary function of some Mycoplasma pneumoniae pneumonia showed reversible airflow limitation,and the airway resistance was significantly improved.4.Pulmonary function examination is helpful to assess the type of pulmonary function damage and measure airway responsiveness in children with Mycoplasma pneumoniae pneumonia.The bronchodilation test FEV1 improvement rate ≥12%has clinical significance in predicting the occurrence of asthma-related symptoms after Mycoplasma pneumoniae pneumonia. |
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