Beyond forced exhalation: impulse oscillometry as a promising tool for bronchial hyperresponsiveness evaluation.

Introduction: The multiple forced expiratory maneuvers that must be performed during methacholine test require a high degree of collaboration and can lead to fatigue. However, impulse oscillometry (IOS) is a noninvasive test, quick and easy to perform, that does not require effort-dependent maneuvers.Objectives: The primary endpoint was to evaluate the relationship between IOS and spirometry during the methacholine test. The secondary endpoint was to study the predictive value of baseline IOS in the development of bronchial hyperreactivity.Methods: Observational, prospective, cross-sectional study, with recruitment of consecutive patients from the pulmonology department with clinical suspicion of bronchial asthma with negative bronchodilator test and normal FeNO.Results: Twenty-five patients were included, with a mean age of 49 ± 18 years. Thirteen patients (52%) had a positive methacholine test. The correlation between IOS indices and FEV1 was significant (p < 0.05) in all cases. The indices with the highest predictive power were R5-20 and AX. The optimal cutoff points were an increase of greater than 32.96% in R5, greater than 120.83% for X5, an increase of 30.30 [kPa l-1s-1] in R5-20, and an increase of 1.01 [kPa l-1] for AX. Baseline oscillometry demonstrated a strong predictive value in the development of bronchial hyperreactivity, with a sensitivity of 61.5% and a specificity of 91.7%, using the cut-off point of 160.0% for R5.Conclusions: IOS may be a valuable alternative to forced spirometry in detecting bronchial hyperreactivity during the methacholine test, showing a good correlation between both tests.

Evaluation of the Diagnostic Accuracy of Non-Specific Bronchial Provocation Tests in the Diagnosis of Asthma: A Randomized Cross-Over Study

Introduction: The role of bronchial provocation tests in the diagnosis of asthma remains to be fully explored. We aimed to evaluate methacholine and mannitol challenge testing, and explore the factors associated with this broncoprovocation response.Methods: Observational, cross-over, randomized trial evaluating adult cases with suspected asthma, naïve to treatment, with normal pre-bronchodilator spirometry, and negative bronchodilator test. Patients were randomized to start with methacholine or mannitol. The diagnosis of bronchial asthma was confirmed if there was a good functional and clinical response to one month with twice daily formoterol/budesonide 9/320. The diagnostic profile and the concordance were calculated. Factors associated with a positive provocation test were entered into a multivariate binomial logistic regression analysis, and classification trees were created for both tests.Results: The study included 108 cases (50.0% diagnosed with asthma and 51.9% cases starting with methacholine). The percentage of cases positive to methacholine and mannitol were 30.6% and 25.0% respectively. Kappa values were 0.40 (p<0.001). The diagnostic profile for methacholine was sensitivity 59.3% and specificity 98.1%, while for mannitol it was sensitivity 48.1% and specificity 98.1%. Variables associated with a positive methacholine response included sex, atopy, FEV1, FEV1/FVC and FENO, whereas they were FEV1/FVC and FENO for mannitol. A FENO value>26ppb, FEV1≤103.3% and female sex correctly classified 78.7% of methacholine responders. FENO value>26ppb was enough to correctly classify 81.5% of mannitol responders.Conclusions: Our study confirms the diagnostic profile of methacholine and mannitol challenge tests and describes the variable associated to their positivity with new proposed cutoff values. (AU)

Evaluation of the Diagnostic Accuracy of Non-Specific Bronchial Provocation Tests in the Diagnosis of Asthma: A Randomized Cross-Over Study.

INTRODUCTION: The role of bronchial provocation tests in the diagnosis of asthma remains to be fully explored. We aimed to evaluate methacholine and mannitol challenge testing, and explore the factors associated with this broncoprovocation response. METHODS: Observational, cross-over, randomized trial evaluating adult cases with suspected asthma, naïve to treatment, with normal pre-bronchodilator spirometry, and negative bronchodilator test. Patients were randomized to start with methacholine or mannitol. The diagnosis of bronchial asthma was confirmed if there was a good functional and clinical response to one month with twice daily formoterol/budesonide 9/320. The diagnostic profile and the concordance were calculated. Factors associated with a positive provocation test were entered into a multivariate binomial logistic regression analysis, and classification trees were created for both tests. RESULTS: The study included 108 cases (50.0% diagnosed with asthma and 51.9% cases starting with methacholine). The percentage of cases positive to methacholine and mannitol were 30.6% and 25.0% respectively. Kappa values were 0.40 (p<0.001). The diagnostic profile for methacholine was sensitivity 59.3% and specificity 98.1%, while for mannitol it was sensitivity 48.1% and specificity 98.1%. Variables associated with a positive methacholine response included sex, atopy, FEV1, FEV1/FVC and FENO, whereas they were FEV1/FVC and FENO for mannitol. A FENO value>26ppb, FEV1≤103.3% and female sex correctly classified 78.7% of methacholine responders. FENO value>26ppb was enough to correctly classify 81.5% of mannitol responders. CONCLUSIONS: Our study confirms the diagnostic profile of methacholine and mannitol challenge tests and describes the variable associated to their positivity with new proposed cutoff values.

New data analysis in a population study raises the hypothesis that particle size contributes to the pro-asthmatic potential of small pet animal allergens.

BACKGROUND: The size of inhaled particles influences where they deposit and theoretically should be important for the development of airway inflammation and responsiveness. Our aim was to assess if sensitization to smaller-sized aeroallergens relates to higher prevalence of treated asthma, increased airway responsiveness, and airway and systemic inflammation. METHODS: Molecular-based IgE antibody determination was done in 467 subjects. Sensitized subjects were grouped based on the particle size of the aeroallergen: (1) Large particles only (mainly pollen); (2) Medium-sized particles (sensitized to mainly mite and mold and possibly to large particles); and 3) Small particles (sensitized to pet allergens and possibly to medium- and/or large-sized particles). Airway responsiveness to methacholine, exhaled nitric oxide (FENO), and serum eosinophil cationic protein (S-ECP) were measured. Asthma and rhinitis were questionnaire-assessed. RESULTS: Subjects sensitized to small particles had higher prevalence of treated asthma (35% versus 10%, P < 0.001), higher FENO50 (32 versus 17 ppb, P < 0.001), higher S-ECP (10 versus 7.5 ng/mL, P = 0.04), and increased bronchial responsiveness (dose-response slope, 5.6 versus 7.5, P < 0.001) compared with non-atopics. This was consistent after adjusting for potential confounders. Sensitization to only large or to medium and possibly also large aeroallergen particles was not related to any of these outcomes after adjustments. CONCLUSIONS: Sensitization to smaller particles was associated with a higher prevalence of asthma under treatment, higher airway responsiveness, and airway and systemic inflammation. Mapping of IgE sensitization to small particles might help to detect subjects having increased airway and systemic inflammation and bronchial responsiveness, indicating increased risk of developing asthma.

Exercise-induced bronchospasm diagnosis in children. Utility of combined lung function tests.

BACKGROUND: The diagnosis of exercise-induced asthma or bronchospasm (EIB) is a complex dare in daily clinical practice. The consensus is that if bronchial hyper-responsiveness (BHR) is demonstrated in a patient with symptoms consistent with EIB, then that patient can be diagnosed with exercise-induced bronchospasm. The aim of this study was to determine which BHR test is the most efficient to diagnose EIB. METHODS: Children under 16, without previous asthma diagnosis, or with stable asthma, complaining of asthma-like symptoms triggered by exercise were included. Bronchodilator, methacholine, mannitol, and exercise tests were performed on all patients, following established protocols. The performance of single and combined tests was determined. RESULTS: Of 46 patients (median age: 12 yr, ranged 8-16 y.o.) were recruited, 30 (70%) previously diagnosed of asthma. BHR was detected in 93.47% of the children. The exercise challenge test detected BHR in 11 of 46 (23.90%) patients, bronchodilator test in 10 of 46 (21.70%), mannitol in 36 of 45 (80%) and methacholine in 41 of 45 (91.11%). The total number of patients with BHR was detected using a combination of the methacholine and mannitol tests. A combination of the methacholine test performed first, followed by the mannitol test, was able to diagnose BHR in 100% of children with lower number of tests (n = 45) than if the order was reversed (n = 50). CONCLUSIONS: Methacholine and mannitol tests detect BHR in most children with suspected EIB. Bronchodilator and exercise tests show a low positivity rate. A combination of the methacholine test, followed by the mannitol test, gives the highest return to identify BHR in children for the diagnosis of EIB.

Small airway impairment and bronchial hyperresponsiveness in asthma onset.

PURPOSE: Our study tried to find a relationship between baseline FEF25-75% and airway hyperresponsiveness (AHR) and whether a greater FEF25-75% impairment may be a marker of a more severe hyperresponsiveness in subjects with normal FEV1 and FEV1/FVC and suggestive asthma symptoms. Besides, we tried to asses a FEF25-75% cut-off value to identify hyper-reactive subjects. METHODS: 4,172 subjects (2,042 M; mean age: 38.3±14.9; mean FEV1 % predicted: 100.5±12.7 and FEV1/FVC: 85.4±6.8) were examined after performing a methacholine (Mch) test. All subjects reported a symptom onset within 3 years before the test. Subjects with PD20<400 or >400 µg were arbitrarily considered affected by moderate/severe and borderline AHR, respectively. RESULTS: PD20 values were 213 (IQR:86-557), 340 (IQR:157-872) and 433 (IQR:196-1032) µg in subjects with baseline FEF25-75≤50%, FEF25-75 between 50 and 70% and FEF25-75>70% respectively (P<0.0001). Only in moderate/severe hyper-reactive subjects (excluded borderlines), PD20 was lower in the FEF25-75≤50% subgroup than in the 1 with FEF25-75>70%. The hyperreactive subjects percentage, was higher in those with FEF25-75≤50% and lower in those with FEF25-75>70% (P<0.0001). FEF25-75<50% (compared to FEF25-75>70%) was a higher AHR risk factor, especially in subjects with moderate/severe AHR (OR: 2.18 [IQR:1.41-3.37]; P<0.0001). Thresholds yielding the highest combined sensitivity/specificity for FEF25-75% were 75.19 (area under curve [AUC]: 0.653) and 74.95 (AUC:0.688) in subjects with PD20<2,400 and <400 µg respectively. FEV1, FVC, and FEV1/FVC measured in subjects with different FEF25-75≤50%, FEF25-75>50 and ≤70% or FEF25-75>70% levels were similar both in normoreactive and hyperreactive subjects. CONCLUSIONS: At asthma onset, reduced baseline FEF25-75 values with normal FEV1 and FEV1/FVC may predict AHR. Detectable predictive cut-off values do not exist because even normoreactive subjects can show lower FEF25-75 values. Furthermore, a greater FEF25-75 reduction may be associated to a more severe AHR, suggesting a possible FEF25-75 role in the management of asthma when FEV1 and FEV1/FVC are normal.

Small Airway Impairment and Bronchial Hyperresponsiveness in Asthma Onset

PURPOSE: Our study tried to find a relationship between baseline FEF25-75% and airway hyperresponsiveness (AHR) and whether a greater FEF25-75% impairment may be a marker of a more severe hyperresponsiveness in subjects with normal FEV1 and FEV1/FVC and suggestive asthma symptoms. Besides, we tried to asses a FEF25-75% cut-off value to identify hyper-reactive subjects. METHODS: 4,172 subjects (2,042 M; mean age: 38.3+/-14.9; mean FEV1 % predicted: 100.5+/-12.7 and FEV1/FVC: 85.4+/-6.8) were examined after performing a methacholine (Mch) test. All subjects reported a symptom onset within 3 years before the test. Subjects with PD20400 microg were arbitrarily considered affected by moderate/severe and borderline AHR, respectively. RESULTS: PD20 values were 213 (IQR:86-557), 340 (IQR:157-872) and 433 (IQR:196-1032) microg in subjects with baseline FEF25-7570% respectively (P70%. The hyperreactive subjects percentage, was higher in those with FEF25-7570% (P70%) was a higher AHR risk factor, especially in subjects with moderate/severe AHR (OR: 2.18 [IQR:1.41-3.37]; P50 and 70% levels were similar both in normoreactive and hyperreactive subjects. CONCLUSIONS: At asthma onset, reduced baseline FEF25-75 values with normal FEV1 and FEV1/FVC may predict AHR. Detectable predictive cut-off values do not exist because even normoreactive subjects can show lower FEF25-75 values. Furthermore, a greater FEF25-75 reduction may be associated to a more severe AHR, suggesting a possible FEF25-75 role in the management of asthma when FEV1 and FEV1/FVC are normal.

The association between reflux esophagitis and airway hyper-reactivity in patients with gastro-esophageal reflux.

BACKGROUND: The association of gastro-esophageal reflux (GER) with a wide variety of pulmonary disorders was recognized. We aimed to evaluate the effect of GER-induced esophagitis on airway hyper-reactivity (AHR) in patients and the response to treatment. MATERIALS AND METHODS: In this cohort study, 30 patients attending the gastrointestinal clinic of a university hospital with acid reflux symptoms were included. All patients were evaluated endoscopically and divided into case group with esophagitis and control group without any evidence of esophagitis. Spirometry and methacholine test were done in all patients before and after treatment of GER with pantoprazole 40 mg daily for six months. RESULTS: There was a significant difference in the rate of positive methacholine test between the cases (40%) and the controls (6.7%) prior to anti-acid therapy (P < 0.0001). After six months of treatment, the frequency of positive methacholine test diminished from 40 to 13.3% in the case group (P < 0.05) but did not change in the controls (P = 0.15). CONCLUSION: The presence of esophagitis due to GER would increase the AHR and treatment with pantoperazole would decrease AHR in patients with proved esophagitis and no previous history of asthma after six months.