Bronchial provocation determined by breath sounds compared with lung function.

Bronchial provocation testing with methacholine was undertaken in 15 children aged 5 to 8 years with obstructive lung disease, mostly asthma (13/15). The methacholine was inhaled during two minutes of tidal breathing in increasing concentrations. After each inhalation, lung function was measured and clinical signs recorded independently by two observers unaware of each other''s results. The logarithm of the concentration of methacholine which caused wheezing over the trachea correlated closely with the logarithm of the concentration of methacholine causing a 20% fall in the forced expiratory volume in one second (FEV1) but was 52% greater on average. At the end of the test there was a mean (SD) fall in FEV1 of 33.3 (7.4)% and a fall in oxygen saturation of 5.2 (3.1)%. Bronchial provocation testing by listening for wheeze over the trachea is a safe technique, which correlates with objective measures of lung function in young children.     

Airway response to exercise and methacholine in children with respiratory symptoms.

Thirty atopic and 30 non-atopic subjects were identified from a population of 7-8 year old children with current respiratory symptoms. The response of the airways to exercise and provocation by methacholine were compared. In these children, who had symptoms but were not necessarily asthmatic, there was no significant correlation between the two stimuli. The atopic children were, however, significantly more responsive than the non-atopic children to both. For the whole group, odds ratios derived for atopy and for an increased response to methacholine (expressed as a PD20--the dose that caused the forced expiratory volume in one second (FEV1) to fall by 20%--of less than 6.4 mumol/l), a positive exercise test (greater than 15% fall in FEV1), and the presence of asthma were 13.5, 3.3, and 21.0, respectively; that for positive response to methacholine and positive exercise challenge was 1.5. Thus though increased bronchial responsiveness to methacholine and exercise challenge are both associated with a diagnosis of asthma, the association between the two stimuli is complex, and supports the view that they reflect entirely different components of airways dysfunction.     

Correlation between spirometry and impulse oscillometry in children with asthma

AIM: In certain patients, such as young children or individuals with cerebral palsy or severe mental retardation, it is difficult to perform forced expiratory manoeuvres to measure expiratory flow volume. In such cases, we could evaluate obstructive lung disease through the measurement of airway resistance instead of expiratory flow volume. METHODS: In this study, we evaluated the correlation of Impulse Oscillometry (IOS) parameters with spirometry values and peak expiratory flow rate (PEFR) measurements to give coherence to IOS recordings in lung function exploration. Total serum IgE levels, total eosinophil counts and specific IgE levels were measured in 48 children with asthma and 66 control subjects, aged 7-15 years of age. IOS, spirometry and PEFR measurements were performed, as well as methacholine challenge. We further analyzed the correlations in atopic asthma, atopic control, nonatopic asthma and nonatopic control groups. RESULTS: FEV(1) and PEFR showed a significant correlation with impedance and resistance (R) at 5, 10, 20 and 35 Hz, both in atopic asthmatic and in atopic control children. FVC also showed a correlation with impedance and R at 10, 20 and 35 Hz, both in atopic asthmatic and atopic control children. FEF(25-75%) did not show a correlation with resistances. CONCLUSION: FEV(1), FVC and PEFR were significantly correlated with IOS parameters, in both asthmatic and control subjects, especially for atopic children. IOS could be used as a suitable measure of lung function when spirometry and PEF cannot be performed.     

Specificity and sensitivity of methacholine challenge test in children with normal and hyperreactive airways

To assess the ability of the methacholine challenge test for separation between normals and patients with clinically apparent mild airway hyperreactivity, the provocative dose of inhaled methacholine required to cause a 20% drop in the forced expiratory volume in one second was evaluated in two selected pediatric populations. On the basis of a standardized respiratory questionnaire, 70 subjects, 4-16 years of age were identified. Included were 49 normal individuals, and 21 individuals with mild airway hyperreactivity who responded to bronchodilators. Methacholine inhalation challenges were performed by use of a standard inhalation procedure. Forty-seven percent of the normals (23/49) had a positive methacholine challenge test while 24% (5/21) of the patients with hyperreactive airways had a negative test by the standard criteria. A wide spectrum of specificity and sensitivity of methacholine challenge was obtained at different doses of methacholine. The greater the sensitivity, the lower the specificity. Therefore, we postulate that the methacholine challenge test can be helpful in making the clinical diagnosis but it does not allow a clear and perfect separation between normal and clinically apparent mildly airway reactive patients in a pediatric age population.     

Specificity and Sensitivity of Methacholine Challenge Test in Children with Normal and Hyperreactive Airways

ABSTRACT. To assess the ability of the methacholine challenge test for separation between normals and patients with clinically apparent mild airway hyperreactivity, the provocative dose of inhaled methacholine required to cause a 20% drop in the forced expiratory volume in one second was evaluated in two selected pediatric populations. On the basis of a standardized respiratory questionnaire, 70 subjects, 4-16 years of age were identified. Included were 49 normal individuals, and 21 individuals with mild airway hyperreactivity who responded to broncho-dilators. Methacholine inhalation challenges were performed by use of a standard inhalation procedure. Forty-seven percent of the normals (23/49) had a positive methacholine challenge test while 24% (5/21) of the patients with hyperreactive airways had a negative test by the standard criteria. A wide spectrum of specificity and sensitivity of methacholine challenge was obtained at different doses of methacholine. The greater the sensitivity, the lower the specificity. Therefore, we postulate that the methacholine challenge test can be helpful in making the clinical diagnosis but it does not allow a clear and perfect separation between normal and clinically apparent mildly airway reactive patients in a pediatric age population.     

Outcome of children with respiratory symptoms without objective evidence of asthma: a two-year, prospective, follow-up study

This study evaluated the outcome of 33 children with asthma-like symptoms without objective evidence of asthma, and the role of certain factors in predicting the development of clinical asthma in these children. Data on symptom histories, lung functions (flow-volume spirometry, free running test and methacholine inhalation challenge test) and atopic sensitization (skin prick tests and markers of eosinophilic inflammation) were collected twice with an interval of 2 y, and the diagnoses were re-evaluated after the follow-up period. Based on the results, it was concluded that one-third of the children with prolonged or recurrent lower airway symptoms, such as cough or wheeze, either have mild asthma or will develop asthma in the near future. Children who had a significant response [≥ 10% fall in forced expiratory volume in 1 s (FEV1)] in the free running test formed a risk group for active asthma, whereas other baseline characteristics seemed not to predict the outcome.     

Responses of plasma vasoactive intestinal polypeptide to methacholine and exercise loading in children and adolescents with bronchial asthma

Responses of plasma vasoactive intestinal polypeptide (VIP) to methacholine inhalation and to exercise loading were studied in asthmatic patients to clarity a significant role of the peptidc. The mean of basal VIP in asthmatics was not significantly different from the normals. The levels were increased after FEV (1. 0) (forced expiratory volume in a second) decreased to 80% of the baseline following methacholine inhalation and were returned to values similar to the baseline when FEV (1. 0) recovered to 100%. Thirty minutes after the exercise, mean VIP was significantly lower in patients with the lowest FEV (1. 0). These results suggest that VIPergic system contributes, at least partly, to relax constricted bronchioles in some patients with bronchial asthma.     

不同体重指数的哮喘患儿规范化激素治疗后肺功能变化

目的：研究不同体重指数（BMI）的哮喘患儿经吸入糖皮质激素（ICS）治疗后肺功能的改善情况。方法：157例哮喘患儿根据BMI分为肥胖组（46例）、超重组（50例）和体重正常组（61例）,检测所有患儿治疗前及规范化ICS治疗1年后,大气道通气功能指标1秒用力呼气容积（FEV1）、用力肺活量（FVC）及小气道通气功能指标用力呼气25%流量（MEF25）、用力呼气50%流量（MEF50）。结果：治疗前各组患儿行肺功能激发试验,雾化吸入乙酰甲胆碱后肥胖组FVC%、FEV1%、MEF25%及MEF50%下降率均明显高于体重正常组（均P<0.01）;雾化吸入沙丁胺醇后肥胖组FEV1%、MEF25%和MEF50%以及超重组MEF25%和MEF50%改善率均明显低于体重正常组（均P<0.05）。ICS治疗1年后,与治疗前相比,体重正常组FVC%、FEV1%均明显升高,而肥胖组和超重组仅FVC%升高。结论：肥胖能够增加哮喘患儿对乙酰甲胆碱敏感性,而抑制对沙丁胺醇反应性;规律ICS治疗能改善正常体重哮喘患儿大气道通气功能,对小气道通气功能影响较小;肥胖能够抑制ICS对哮喘患儿肺功能的改善作用。     

Inhibition of exercise-induced-asthma (EIA) by nedocromil sodium and sodium cromoglycate in children

Nedocromil sodium (Ned) 4 mg, sodium cromoglycate (SCG) 10 mg, and placebo were compared for their efficacy in preventing exercise-induced asthma. Nineteen asthmatic children aged six to 15 years performed a treadmill exercise test before and 20' after a single dose of drug in a double-blind trial. Both active drugs performed significantly better than placebo; in fact the exercise challenge resulted in a mean maximum fall in FEV1 of 26.1 ± 14.9% after placebo, but only of 14.6 ± 11.5% after SCG (P < 0.05), and 11.0 ± 12.4% after Ned (p < 0.01). Measurements of PEFR gave similar results, while the effect of treatment on FEF 25–75 was significant for Ned alone (p < 0.05). Direct comparison between Ned and SCG at different time points demonstrated significant differences in FEV1 at 1 min (p < 0.05) with a better overall performance of Ned. In individual patients, complete protection was provided in 9 patients with SCG, in 14 patients with Ned and in 2 with placebo. No side effects were observed. This study suggests that at the dosages used there are only slight differences between SCG and Ned activity in the prevention of exercise-induced asthma.     

The response to exercise in normal and asthmatic children

Twenty-five normal and 105 asthmatic children were exercised on a treadmill. Pulmonary function was assessed before and after exercise. The maximum fall from the resting value in normal subjects depended on the test used: PEFR 12.5%; FEV1 10%; MMEF 26%; V50 30%; V25 33%. Using these criteria, PEFR and FEV1 detected 99% of those asthmatic children who had a positive exercise response. The largest fall from the resting value was seen with the MMEF, but this test detected only 70% of the positive responders. The pre-exercise function did not affect the severity of the response but did have an effect on the incidence of exercise-induced bronchospasm.     

Is outdoor running exercise suitable for detecting bronchial hyperreactivity in children with mild episodic bronchial asthma?]

Bronchial hyperreactivity (BHR) can be proved by various methods. 21 children, 14 asthmatics and 7 healthy subjects were submitted to inhalative methacholine challenge as well as to 'free running' as a form of exercise challenge in a randomized sequence. For the methacholine inhalation a standardized procedure was followed and the provocative concentration defined (PC20) at which a decrease of more than 20% in FEV1 was found. There is no real standardisation for 'free running' (concerning temperature and humidity of the inspired air; individual level of exercise) but subjects had to run for 6 minutes while the heart rate should have been between 170 and 180 beats/minute. This increase in pulse rate relates to a submaximal work at which 60-85% of maximal O2 uptake are obtained. A decrease of 15% from basic value of FEV1 was defined as a positive result. By the use of methacholine inhalations we found 16 children (14 diseased, 2 controls) to be hyperreactive, whereas only 3 of them showed a positive result after 'free running'. We conclude, that firstly, methacholine provocations and exercise challenges assess different kinds of bronchial reactivity, secondly, 'free running' as a form of exercise is very difficult to standardize and therefore prone to errors and thirdly, 'free running' is not sensitive enough to assess BHR in children with mild asthma bronchiale if used as the only form of challenge. Problems concerning measurement of BHR are discussed.     

The leukotriene D4-receptor antagonist zafirlukast attenuates exercise-induced bronchoconstriction in children

OBJECTIVE: To determine the effects of zafirlukast on exercise-induced bronchoconstriction in children. STUDY DESIGN: Exercise challenges were done 4 hours after single oral doses of zafirlukast or placebo were administered in asthmatic children (6 to 14 years) treated with beta 2-agonists alone. Subjects randomized to treatment had a >/=20% decrease in forced expiratory volume in 1 second (FEV1 ) after a screening challenge. In a randomized, double-blind, 3-way, crossover design, group 1 (n = 20) received placebo and 5 and 20 mg zafirlukast, and group 2 (n = 19) received placebo and 10 and 40 mg zafirlukast. Maximal percentage fall in FEV1, area under the curve, and time to recovery of FEV1 to within 5% of baseline after the challenge were compared with analysis of variance. RESULTS: Mean values for maximal fall in FEV1 ranged from -8.7% +/- 1.7% to -11.1% +/- 1.9% after zafirlukast compared with -17.1% +/- 1.8% and -16.3% +/- 1.9% after placebo. Differences from placebo for fall in FEV1 and area under the curve were significant (P 相似文献   

The relation between adrenal function and the severity of bronchial hyperresponsiveness in children as measured by the methacholine provocation test

BACKGROUND: There is no satisfactory explanation why some individuals experience severe attacks of asthma, yet others, exposed to similar stimuli, have a milder form of the disease. OBJECTIVE: We tested the hypothesis that children with more severe disease may have relative adrenal insufficiency compared to the children with milder disease. PATIENTS AND METHODS: Sixteen children with chronic asthma aged 8-16 years old were studied. Adrenal function was evaluated by the 24-h excretion of urinary free cortisol (UFC) before and after ACTH stimulation, and by plasma cortisol levels before and 60 min after ACTH administration. The severity of bronchial hyperresponsiveness was evaluated by the methacholine provocation test. RESULTS: Nine children had 20% fall in forced expiratory volume in 1 sec (FEV1) after a provocative concentration (PC20FEV1) of methacholine > or =2.5 mg/ml and were considered as having mild-moderate bronchial hyperresponsiveness (Group A). Seven children had a PC20FEV1 of < or =1.25 mg/ml and were considered as having severe bronchial hyperresponsiveness (Group B). No significant difference was found between the peak plasma cortisol response to ACTH between the two groups (634+/-182 and 586+/-137 nmol/l, respectively). However, there was a significant statistical difference (p <0.01) in the 24-h UFC response to ACTH between the children from Group A (345+/-107 nmol/m2 ) and the children from Group B (161+/-125 nmol/m2). CONCLUSIONS: Based on the low levels of 24-h UFC secretion in severely asthmatic children in our study, we propose the encouragement of provision of a short course of inhaled steroids to be kept at home for the emergency therapy of those children identified as having high-risk asthma.     

Acute bronchodilatory effect of salmeterol on methacholine-induced bronchoconstriction in childhood asthma

Abstract A review of the literature highlights the need for research, particularly on the acute bronchodilatory effect of salmeterol on bronchoconstriction in the pediatric age group. The present study attempted to evaluate the acute bronchodilatory effect of salmeterol on methacholine-induced bronchoconstriction in childhood asthma and to compare it with the effect of salbutamol. Forty-four asymptomatic children with mild-to-moderate asthma (23 boys and 21 girls; aged7–17 years) were studied. At the beginning, the baseline forced expiratory volume in 1 s (FEV₁) was measured, and the methacholine challenge was performed by doubling the dose to determine PC₂₀ (provocative concentration of inhaled methacholine required to reduce FEV! by 20%). At the same time, the transcutaneous arterial oxygen saturation (S_ao₂) was also measured. Each subject inhaled a single dose of 25 μ salmeterol (n: 23, group I) or 100 μg salbutamol (n: 21, group II) following the Sp₂ measurement. The same measurements (FEV₁, S_ao₂) were repeated 5 and 20 min after the inhalation. After inhalation of salmeterol or salbutamol, the differences between the values of FEV₁ and S_aO₂ after 5 and 20 min were insignificant in both group I and group II (P > 0.05), although there was a significant improvement in both FEV₁ and S_aO₂ after 5 and 20 min (P < 0.005). From these findings it was concluded that salmeterol can be considered as effective as salbutamol on methacholine-induced bronchoconstriction.     

Prevention of exercise induced asthma by inhaled salmeterol xinafoate.

The effect of inhaled salmeterol xinafoate, a long acting beta 2 agonist, on exercise induced asthma was studied in a double blind, crossover, and placebo controlled trial. Thirteen asthmatic children with a fall of at least 15% in their forced expiratory volume in one second (FEV1) after a standard exercise test on a motorised treadmill, on separate days performed the same test 1, 5, and 9 hours after a single dose of 50 micrograms salmeterol or placebo. FEV1 was measured before treatment, and before and for 30 minutes after each exercise test. After placebo the number of children with exercise induced asthma was: 10 at 1 hour, 11 at 5 hours, and 12 at 9 hours. Salmeterol prevented exercise induced asthma in all 13 children studied, at 1, 5, and 9 hours. Mean maximum falls in FEV1 after exercise were at 1 hour: salmeterol 2.7% and placebo 24.6%, 5 hours: salmeterol 5.3% and placebo 22.7%; and 9 hours: salmeterol 3.4% and placebo 26.6%. After salmeterol the mean increase in FEV1 was 17.8% at 1 hour, 19.6% at 5 hours, and 19.2% at 9 hours. Inhaled salmeterol prevents exercise induced asthma and produces significant bronchodilatation for at least 9 hours.     

Effect of detergent-coated versus non-coated spacers on bronchodilator response in children with asthma

OBJECTIVE: Previous studies have demonstrated that coating spacers with ionic detergents minimizes the static charge and thereby improves in vivo drug deposition. The present study aims to examine the effect of coated spacers versus non-coated spacers in the clinical situation. METHODS: A randomized, double-blind study in children with asthma and a ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) of < or =72% predicted was carried out. Spirometry was performed at baseline and at 10 min and 20 min after inhalation of two puffs of salbutamol (100 microg/puff) through either a detergent-coated or a non-coated spacer. RESULTS: Fifty children were studied (mean age 11.6 years, range 7-18 years): 26 in the group using coated spacers (CG); and 24 in the group using non-coated spacers (NCG). The mean percentage change in FEV1 from baseline 10 min after inhalation was 18.8% (range 5-50%) in the CG versus 18.5% (range 3-35%) in the NCG. At 20 min after inhalation, the per cent increase in FEV1 was 19.8% (range 0-50%) in the CG versus 19.5% (range 9-35%) in the NCG. There was no significant difference between groups in the percentage change in FEV1 after 10 min (P = 0.91), or after 20 min (P = 0.93). CONCLUSIONS: There was no improvement in bronchodilatation from detergent-coated spacers in the present study, possibly because a maximal bronchodilator response was achieved with the lower output.     

Low‐dose budesonide improves exercise‐induced bronchospasm in schoolchildren

The aim of this study was to compare the clinical efficacy of low‐dose inhaled budesonide (once or twice daily) and placebo, administered via Turbuhaler^®, on exercise‐induced bronchoconstriction (EIB) in children with mild asthma. Fifty‐seven steroid‐naive children (7–16 years old; 41 boys, 16 girls) with EIB participated in this sub‐population study according to the following inclusion criterion: a maximum fall in forced expiratory volume in 1 s ( FEV ₁) ≥ 10% after a standardized treadmill test. Mean baseline FEV ₁ was 100.3% of predicted, and mean maximum fall in FEV ₁ after the standardized exercise test was 22%. The study was a double‐blind, randomized, parallel‐group design. After 2 weeks of run‐in, the children received inhaled budesonide 100 µg or 200 µg once daily in the morning, 100 µg twice daily, or placebo, for 12 weeks. After 12 weeks of treatment, the fall in FEV ₁ after the exercise test was significantly less in all three budesonide groups (7.2–7.8%) vs. placebo (16.7%). Daytime symptom scores were significantly lower in all three budesonide groups compared with placebo (p < 0.02). The three budesonide groups did not differ significantly, and no significant change in lung function was found in any group. Therefore children with mild asthma, but with significant EIB, improved their exercise tolerance and symptom control after 3 months of treatment with a low dose of inhaled budesonide given once or twice daily.     

Mycoplasma pneuminia infection. A follow-up study of 50 children with respiratory illness.

Fifty children with a previous history of Mycoplasma pneumoniae respiratory tract infection were assessed clinically, and pulmonary function tests carried out after an interval ranging from 1 1/2 to 9 1/2 years (median 2 1/2). 23 suffered from recurrent wheezy bronchitis or asthma, and in 5 the index illness appeared to precipitate the wheezing tendency. All were symptom-free when respiratory function tests were performed. Simple tests of ventilatory function (PEFR, FEV, and FVC) were within normal limits. Increased bronchial reactivity after exercise (a fall in PEFR greater than 15% resting value) was demonstrated only in children known to have asthma. Maximum expiratory flow rates in air at 50% of vital capacity (V mas50) were within the normal range in all patients with the exception of two. The response in flow rate at 50% of vital capacity after inalation of an 80% helium and 20% oxygen mixture delta V max50) was reduced (P less than 0.001) in asymptomatic patients with a history of M. pneumoniae respiratory infection, when compared with normal data from 48 healthy schoolchildren without a background of significant respiratory illnesses. These findings indicate impairment of small airways function, even in totally symptom-free children in the study group.     

Non-specific bronchial hyper-responsiveness in children with allergic rhinitis: Relationship with the atopic status

An increased prevalence of bronchial hyper-responsiveness (BHR) has been demonstrated in children from a general population, and in non-asthmatic adults with allergic rhinitis. Thus, also children with allergic rhinitis are expected to be at higher risk of BHR. We evaluated the prevalence of BHR in a sample of non-asthmatic children with allergic rhinitis by means of the methacholine (Mch) bronchial challenge, and by monitorizing the airway patency using the daily peak expiratory flow variability (PEFv). Fifty-one children (ranged 6–15 years of age) with allergic rhinitis, ascertained by skin prick test to inhalant allergens, underwent a 14-day peak expiratory flow monitoring, and a Mch bronchial provocation challenge. Thirty healthy children matched for age, and sex served as control group. Thirty-one children in the rhinitis group (61%), and six (20%) in the control group were Mch+ (Mch provocative dose causing a 20% fall of forced expiratory volume in 1 s respect to baseline <2250  μ g, equivalent to 11.50  μ mol). In rhinitic children the PEFv did not significantly differ between Mch+ and Mch− subjects, but the total serum immunoglobulin E (IgE) were higher among Mch+. The persistent form of rhinitis was significantly associated to Mch positivity. Non-asthmatic children with allergic rhinitis displayed a high prevalence of BHR. The BHR was significantly associated with persistent rhinitis and with higher total IgE levels. Nevertheless, the spontaneous changes in airway patency, as expressed by PEFv, were within normal limits both in Mch+ and Mch− children.     

Dose-related effects of nebulized metaproterenol in asthmatic children

The dose-related effects of inhaled 5% metaproterenol solution in asthmatic children between the ages of six and 12 years with acute bronchospasm were evaluated. Tests included FEV1.0, FEF25-75, and PEFR. For entry into the study, subjects were required to have an FEV1.0 or an FEF25-75 less than 80% of the child's predicted normal value based on height and race. Sixty children were randomly assigned in double-blind fashion to receive one of four different doses of 5% metaproterenol inhalant solution: 0.0 ml (placebo), 0.1 ml, 0.2 ml, or 0.3 ml. Drug efficacy was assessed by spirometry using a DeVilbiss Surveyor I spirometer. Spirometry was performed prior to inhalation of the test dose (baseline) and four times after inhalation: immediately after and 15, 30, and 60 minutes after inhalation. Patients in the three treated groups had significantly higher peak post-dose FEV1.0 and FEF25-75 than the placebo group but were not significantly different from one another. There was a significant relationship between dose and incidence of side effects. These results suggest that 0.1 ml (5 mg) of nebulized metaproterenol may provide as much bronchodilatation as higher doses with fewer side effects.