Methacholine bronchial provocation test in patients with asthma: serial measurements and clinical significance

BACKGROUND/AIMS: The methacholine bronchial provocation test (MBPT) is used to detect and quantify airway hyper-responsiveness (AHR). Since improvements in the severity of asthma are associated with improvements in AHR, clinical studies of asthma therapies routinely use the change of airway responsiveness as an objective outcome. The aim of this study was to assess the relationship between serial MBPT and clinical profiles in patients with asthma. METHODS: A total of 323 asthma patients were included in this study. The MBPT was performed on all patients beginning at their initial diagnosis until asthma was considered controlled based on the Global Initiative for Asthma guidelines. A responder was defined by a decrease in AHR while all other patients were considered non-responders. RESULTS: A total of 213 patients (66%) were responders, while 110 patients (34%) were non-responders. The responder group had a lower initial PC20 (provocative concentration of methacholine required to decrease the forced expiratory volume in 1 second by 20%) and longer duration compared to the non-responder group. Members of the responder group also had superior qualities of life, compared to members of the non-responder group. Whole blood cell counts were not related to differences in PC20; however, eosinophil concentration was. No differences in sex, age, body mass index, smoking history, serum immunoglobulin E, or frequency of acute exacerbation were observed between responders and non-responders. CONCLUSIONS: The initial PC20, the duration of asthma, eosinophil concentrations, and quality-of-life may be useful variables to identify improvements in AHR in asthma patients.

Clinical value of fractional exhaled nitric oxide level in predicting bronchial hyperreactivity in asthmatic children / 国际儿科学杂志

Objective To evaluate the clinical value of fractional exhaled nitric oxide (FeNO) level in asthmatic children to predict bronchial hyperresponsiveness by analyzing the correlation between fraction of exhaled nitric oxide and bronchial provocation test.Methods One hundred and fourteen asthma outpatients of Shengjing Hospital were enrolled, FeNO levels, spirometry and bronchial provocation test were measured.Results In the bronchial provocation test,there were 33 positive and 81 negative cases.The positive group had a significantly higher FeNO levels than the negative ones(19.0 × 10-9 vs.16.0 × 10-9 ,p =0.000).By the ROC curve, the best FeNO cut-off value to predict bronchial hyperresponsiveness was 38.5 × 10-9 with high specificity (92.6％) but relatively low sensitivity (36.4％).There was no relationship between methacholine provocative dose causing a 20％ fall in FEV1 (PD20-FEV1) and the level of FeNO.Conclusion FeNO level has important predicting value for bronchial hyperreactivity in children with asthma.The level of FeNO ＞ 38.5 × 10-9 has high predictive value in asthmatic children with bronchial hyperreactivity.

Usefulness of Percutaneous Oxygen Saturation Monitoring as a Predictor of Deterioration of Lung Function in Korean Children with Asthma / 소아알레르기및호흡기학회지

PURPOSE:Our study was designed to verify the correlation between the level of percutaneous arterial oxygen saturation (SpO2) and forced expiratory volume in 1 second (FEV1) and to classify the severity according to SpO2 level when asthma exacerbation is developed. METHODS:We performed the methacholine bronchial provocation tests with monitoring SpO2 on 350 children who visited the pediatric allergy clinic with chronic cough or recurrent wheezing from August 2006 to August 2008. RESULTS:There was a significant correlation between FEV1%fall and SpO2 (r=-0.814, P< 0.01). The mean value of SpO2 was 95.80%+/-1.2% when decrement of FEV1 was 20%. It was 92.3%+/-0.81% when FEV1 decreased by 40%. CONCLUSION:Monitoring SpO2 is a convenient and reliable objective method to determine an appropriate therapeutic option when the pulmonary function test or arteial blood gas analysis is not available in children with asthma. We suggest less than 96% of SpO2 for the moderate attack, less than 92% for the severe attack, as the criteria for the severity of asthma exacerbations in Korea, which is higher than those suggested by GINA guideline or Japanese guidelines.

Usefulness of FEF25-75% in Methacholine Bronchial Provocation Test in Children with Asthma / 소아알레르기및호흡기학회지

PURPOSE: Although asthma is generally understood as a disease of the the small airways, FEF25-75%, an index representing peripheral small airways, is a appropriately used in the diagnosis of asthma. The objectives of this study are to assess the usefulness of FEF25-75% in children with asthma for clinical application. METHODS: Five hundred sixty two 5- to 15-year-old children with symptoms suggestive of asthma were enrolled. Methacholine bronchial provocation tests were performed and the children were divided into two groups according to their test results. RESULTS: Forced expiratory flow between 25-75 percent of vital capacity (FEF25-75%) was significantly lower in asthma group (P< 0.001). A 25 percent fall of FEF25-75% of percentage predicted value was correlated with PC20FEV1 (provacation concentration of methacholine required to reduce FEV1 by 20 percent) (r=0.601, P< 0.001). The sensitivity of PC25FEF25-75% (provocation concentration of methacholine required to reduce FEF25-75% by 25 percent) was 94.11 percent when PC20FEV1 was a point of reference. Youden's index was 0.64. CONCLUSION: FEF25-75% is an useful and sensitive index that predicts the presence or absence and the degree of bronchial hyperresponsiveness and PC25FEF25-75% should be brought into clinical application in asthmatic children.

A Study of Clinical Correlations between Skin Test, Radioallergosorbent Test and Bronchial Provocation Test in House Dust Asthmatics

We evaluated the correlations between the allergy skin test for house dust radioallergosorbent test (RAST) and the bronchial provocation test for revealing the sensitivity of the skin test and RAST, and for aiding in the search for the causative allergen in house dust asthmatics. There was an overall 72.5% agreement between the prick test and RAST, a 73.8% agreement between the prick test and house dust bronchoprovocation test (HD-BPT), and a 71.3% agreement between HD-BPT and RAST. A positive RAST was found with a positive HD-BPT in 71.2% of cases, and if RAST was negative, HD-BPT was negative in 46.9% of cases. 69.6% of the positive cases on prick test (more than 21 mm of erythema) were positive with RAST. All of the cases with a negative skin reaction to the prick test were negative to RAST. A positive skin test was found with a positive HD-BPT in 77.1% of cases, and if the prick test was negative, the HD-BPT was negative in 50.0% of cases. 87.5% of cases with a RAST positive exhibited a positive result with HD-BPT. A significant correlation was found between the results of prick tests and those of RASTs in the early response group of HD-BPT, but not in the late and dual response groups. There were significant correlations between total serum IgE and the results of HD-BPT, and total serum IgE value and the results of RAST. The greater the size of the prick test, the greater the likelihood of a positive HD-BPT. All 5 cases with an end point of intradermal skin test of a 5 degrees -5(-l) X 10(-2) dilution of house dust noted a negative HD-BPT. There was no significant correlation between total serum IgE and total eosinophil count. There was no significant correlation between wheal and erythema size of prick test and PC20 of methacholine.