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Objective To investigate the clinical significance of children bronchial asthma detection by using negative expiratory pressure (NEP) technique.Methods The children with bronchial asthma admitted to Department of Pediatrics of Zhejiang Provincial Integrated Traditional Chinese and Western Medicine Hospital from March 2016 to March 2018 were enrolled.They were divided into mild group (0-4 scores) and severe group (5-12 scores) according to asthma clinical scoring criteria.The children undergoing physical examination at the same period were served as healthy control group.NEP technique and tidal volume (VT) were detected by the pulmonary function instrument.Respiratory flow-volume curves (F-V curves) without NEP were compared with tidal F-V curves after NEP application to assess expiratory flow limitation (EFL).EFL index was calculated according to the percentage of expiratory VT after EFL and expiratory VT when NEP was not used.Pearson correlation method was used to analyze the relationship between EFL index and severity of bronchial asthma.Receiver operating characteristic (ROC) curve was plotted to analyze the value of EFL index in evaluating the severity of bronchial asthma in children.Results A total of 86 children with bronchial asthma were enrolled in the study,and 84 patients completed the test and 2 children withdrew due to other diseases.Finally,84 patients were included in the final analysis,including 41 mild and 43 severe children.Forty-two healthy children in the same period were served as healthy control group.There was no significant difference in gender or age among the groups,and no adverse reactions occurred during the test.The EFL index of children with bronchial asthma was significantly higher than that of the healthy control group,and it was increased with the severity of the disease [mild group compared with healthy control group:(30.60± 6.03)％ vs.(6.64 ± 2.37)％,severe group compared with healthy control group:(33.70 ± 5.41)％ vs.(6.64 ± 2.37)％,both P ＜ 0.05].There was no significant difference in respiratory rate (RR) or VT between mild group or severe group and healthy control group [RR (times/min):31.45 ± 4.18,32.81 ± 4.07 vs.31.97 ± 4.01,VT (mL/kg):6.29 ± 1.14,5.96 ± 0.90 vs.6.30 ± 1.20,all P ＞ 0.05].It was shown by the correlation analysis that EFL index was positively correlated with the severity of asthma (r =0.836,P =0.000).It was shown by ROC curve analysis that the area under ROC curve (AUC) of EFL index for predicting the severity of bronchial asthma in children was 0.801 [95％ confidence interval (95％C/) =0.725-0.878];when the best cut-off value of EFL index was 29.21％,the sensitivity was 85.7％,the specificity was 69.2％,the positive predictive value was 75.1％,and the negative predictive value was 60.2％.Conclusions The EFL index measured by NEP technology was closely related to the severity of bronchial asthma.The higher the EFL index,the more serious of the condition.The severity of bronchial asthma could be early judged by EFL index,which provided a basis for the evaluation and treatment of bronchial asthma.
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Objective The purpose of this study was to evaluate the feasibility of expiratory flow limitation(EFL) detected by negative(NEP) and the correlation between EFL and routine lung function measurements(Forced expiratory volume in first second,FEV1),EFL and MRC dyspnea scale,in patients with stable and acute asthma,to find a simple,reliable and objective method for the diagnosis,differential diagnosis,the severity of disease and evaluation of severity and efficacy of treatment for asthma,and a objective method reflecting the severity of dyspnea.Methods Sixty-four children enrolled in No.306 Hospital of PLA from Jun.to Dec.in 2012 were included in this study.The severity of dyspnea was rated according to the dyspnea scale proposed by the Medical Research Council(MRC).Then routine pulmonary ventilation function tests and NEP technique were performed respectively.Result (1) All asthmatic patients tolerated NEP well.(2) Pulmonary ventilation function tests:The mean FEV1 in 64 was 71.33 ± 13.92％ pred.(3) MRC dyspnea scale:MRC dyspnea scale was 2 in 10,1 in 54 of 64 children with stable asthma.The Spearman' s correlation coefficient of MRC dyspnea scale with FEV1 was-0.635(P ＜0.05).(4)EFL detected by NEP:There were no EFL in 46 children with asthma both in seated and supine positions.There were EFL in 8 children both in seated and supine positions and in 10 only in supine position..The Spearman's correlation coefficient of three-point EFL score with FEV1 and MRC dyspnea scale was-0.607 and 0.964(P ＜ 0.05) respectively.The Spearman's correlation coefficient of five-point EFL score with FEV1 and MRC dyspnea scale was-0.626 and 0.966 (P ＜ 0.05)respectively.Conclusion (1) NEP technique can be used in children with asthma.(2) There was a significant correlation between EFL detected by NEP technique and FEV1.(3) There is a stronger correlation between EFL and MRC dyspnea scale than that between FEV1 and MRC dyspnea scale.
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Objective To evaluate the reproducibility of Negative Expiratory Pressure(NEP)technique in detecting expiratory flow limitation (EFL) on chronic obstructive pulmonary disease (COPD) patients. Methods EFL was evaluated with NEP technique in 72 subjects having stable COPD on two occasions. Agreement between testing occasions was assessed with the κ statistic for the 3-point and 5-point EFL scores, and with paired t-test for FL index. Results On the first testing occasion, 18 subjects had no EFL, 18 subjects had EFL in the supine position, and 36 subjects in the sitting and the supine position. Using the 3-point score, agreement was present in 58 of the 72 subjects at time 2 (κ =0.69, P＜0.001 ), indicating a substantial agreement was found. Using the 5-point score, agreement was seen in 52 of the 72 subjects (κ =0.65, P＜0.001 ), also indicating a substantial agreement. The difference of FL index between the first and the second occasion was significant in both the sitting (P＜0.05) and supine (P＜0.05) positions. Conclusion Both 3-point and 5-point scores provided a reproducible assessment of EFL on COPD patients but the FL index seemed less reproducible. More research were needed before NEP technique was promoted to be used clinically.
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Objective To compare negative expiratory pressure (NEP)technique with conventional test in detecting expiratory flow limitation (EFL)in chronic obstructive pulmonary diseases( COPD) patients. Methods EFL was measured with NEP technique and conventional method respectively in 72 COPD patients;EFL was measured with NEP technique in 20 COPD patients who failed to perform conventional test. Results EFL was detected in 54 of the 72 COPD patients. NEP test was successfully performed on the 20 patients, and 19 of them were found with EFL. The level of forced expired volume in one second percentage( FEV_1 % ) of the patients with 2-score group (46. 92 ± 12. 74) % and 3-score group (33. 35 ± 8.96)% were significantly lower than that of the 1-score group(63. 60 ±16.65)%. Area under curve of NEP technique and conventional test in ROC is 0. 903 and 0. 761 respectively. Conclusions As compared with conventional test, EFL detected with NEP technique is more reliable in evaluating dyspnea of COPD patients. It is simple and doesn't require any cooperation of the patients. NEP technique can be applied in COPD patients who fail to receive conventional test.
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Objective To explore the significance of negative expiratory pressure technique in detecting expiratory flow limitation in chronic obstructive pulmonary disease (COPD) patients. Methods Negative expiratory pressure technique was performed in 13 special COPD patients who did not accomplish routine pulmonary function tests. Results Negative expiratory pressure technique was executed successfully in 13 special COPD patients without any side-effects. Expiratory flow limitation was detected in 12 special COPD patients. 5-point expiratory flow limitation score was significantly correlated with Medical Research Council (MRC) dyspnea score, which was a predictor of dyspnea. Conclusions Negative expiratory pressure technique provides a test which is simple, rapid, noninvasive and does not require any initiative cooperation from the patients, it can be applied in special COPD patients who can not accomplish routine pulmonary function tests.