Relationship between response to inhaled salbutamol and methacholine bronchial provocation in children with suspected asthma

Assessment of airway responsiveness by bronchoprovocation and bronchodilatation tests is important in the diagnostic work-up protocol of bronchial asthma and it would be convenient to undertake both tests on the same occasion. However, it is not known whether this can be done accurately. Therefore, this study evaluated the effect of a prior bronchial provocation test on the bronchodilator response to salbutamol after spontaneous recovery of the forced expiratory volume in one second (FEV1) in a group of asthmatic subjects. On two separate occasions at the same time of day, concentration-response studies with inhaled histamine or methacholine, or a sham challenge with normal saline were carried out in a blinded, randomized manner. Changes in airway calibre were followed as FEV1 and agonist responsiveness expressed as the provocative concentration causing a 20% fall in FEV1 (PC20). After either spontaneous recovery or a fixed-duration wait of 45 min (when appropriate), the subjects received 2x100 microg of salbutamol from a metered dose inhaler with a spacer. The bronchodilator response to salbutamol was expressed as a percentage of initial FEV1 (deltaFEV1% init). Bronchial challenge with both agonists failed to alter significantly the airway response to salbutamol, with the deltaFEV1% init mean value (range) being 16.9% (9.0-31.9) and 17.5% (11.6-31.2) on the sham and histamine/methacholine challenge day respectively. It was shown that the degree of bronchodilatation achieved after salbutamol 200 microg is not affected by prior bronchoprovocation testing when enough time is allowed for the airways to recover spontaneously to baseline forced expiratory volume in one second. Thus evaluation of airway responsiveness by both bronchial provocation tests and bronchodilator testing can be assessed reliably within a few hours in asthmatic patients.

Section: Discussionsupporting

confidence: 59%

Bronchodilator response to salbutamol after spontaneous recovery from nonspecific bronchial provocation tests in asthma

Polosa¹,

Prosperini²,

Magrì³

et al. 1998

“…Similarly, we found a significant, albeit weak, correlation between BDR and methacholine PC20. On the contrary, there are other reports that BDR is not related to methacholine responsiveness [10,11]. The reasons for these conflicting data are unclear, but they are presumably due to confounding factors such as airway remodelling.…”

Section: Discussionmentioning

confidence: 46%

“…Indeed, provocation challenges, when contraindicated for reason of severe airway obstruction, have been replaced by bronchodilator tests. However, studies on the relationship between BHR to histamine or methacholine and BDR have yielded conflicting results; some found a significant correlation [7][8][9], whereas others did not [10,11]. Conversely, there is no information as to whether BDR correlates with BHR to indirect stimuli, such as AMP.…”

mentioning

confidence: 95%

Bronchial hyperresponsiveness to methacholine/AMP and the bronchodilator response in asthmatic children

Suh¹,

Lee²,

Kim³

et al. 2010

Bronchodilator response (BDR) is assessed to estimate the reversibility of airflow obstruction. Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma and is usually measured by means of bronchial challenges using direct or indirect stimuli. The aim of the present study was to compare BHR to methacholine (direct) and that to adenosine 5'-monophosphate (AMP) (indirect) with regard to their relationships to BDR in asthmatic children.Methacholine and AMP challenge tests were performed on 138 children with mild-to-moderate asthma, and the provocative concentration causing a 20% decline in forced expiratory volume in 1 s (FEV1) (PC20) was determined for each challenge. BDR was calculated as the change in FEV1, expressed as a percentage of the initial value, after inhalation of 400 mg salbutamol.Methacholine PC20 correlated significantly but weakly with BDR (r5 -0.254; p50.003). However, there was a significant and strong correlation between AMP PC20 and BDR (r5 -0.489; p50.000). For AMP PC20, the relationship was closer than for methacholine PC20 (p50.024 for comparison between correlation coefficients). The same figures were observed when BDR was expressed as a percentage of the predicted value.A stronger correlation of BDR with AMP PC20 than with methacholine PC20 suggests that BDR may be better reflected by BHR as assessed by AMP challenge than by methacholine challenge.

“…The spacer device used to administer the medication was a Babyhaler® (Glaxo Gmbh, Bad-Oldesloe, Germany) for children under the age of 4.7 yrs and a Volumatic® (Glaxo) above the age of 4.7 yrs. The dose was chosen according to BIBI et al [2].…”

Section: Methodsmentioning

confidence: 99%

“…Reversibility of airway obstruction is considered one of the major criteria in the diagnosis of asthma in children, adolescents and adults [1,2]. Different guidelines for the cut-off value have been proposed for forced expiratory volume in one second (FEV1) and airway resistance (Raw), expressed as either % baseline or as % predicted [3][4][5][6][7][8][9][10].…”

mentioning

confidence: 99%

Bronchodilator response in 3-6.5 years old healthy and stable asthmatic children

Hellinckx¹,

Boeck²,

Bande-Knops³

et al. 1998

131

145

Reversibility of airway obstruction is considered one of the major criteria in the diagnosis of asthma in children, adolescents and adults [1,2]. Different guidelines for the cut-off value have been proposed for forced expiratory volume in one second (FEV1) and airway resistance (Raw), expressed as either % baseline or as % predicted [3][4][5][6][7][8][9][10].Spirometry is hard to perform in children younger than 6 yrs old. Normal values of Raw [11] and of total respiratory resistance (Rrs) measured with the forced oscillation technique (FOT) [12,13] have been established in children [14][15][16]. Not many data are available on bronchodilation tests in asthmatic children younger than 6 yrs. In some of these studies the impulse oscillation system (IOS) was used [17,18], a FOT involving the application of a rectangular pulse signal, whilst in the FOT a pseudorandom noise signal, containing harmonics up to 24 or 48 Hz, is generally used [13]. Both techniques give similar results (r=0.85) over wide ranges of resistance between 0.1 and 1.5 kPa·L -1 ·s [19]. There are, however, no published data on bronchodilator response in healthy children younger than 6 yrs using oscillator techniques. Yet, as already stated, this research is essential [3] to establish the threshold for a significant response in asthmatic children.The aims of the present study were to establish in children aged from 3-6 yrs: 1) normal reference values for the IOS; 2) the change in Rrs and in respiratory reactance (Xrs) after inhalation of a β 2 -agonist in healthy and in asthmatic children; and 3) to propose threshold values for a significant bronchodilator response.The study protocol was approved by the ethical committee of the university hospital. Materials and methodsThe study population consisted of 281 children with a mean age of 4.5 yrs (range 2.7-6.6), a mean height of 108 cm (range 93-131) and a mean weight of 18 kg (range 12-29); 129 males and 152 females. They were recruited from children attending kindergarten (95% of Belgian children between 3-6 yrs do so). During the first and the third year of kindergarten the children have a medical check-up. A standardized questionnaire on the diagnosis of asthma with a form for informed consent was sent to the parents of 480 of these children invited to the centre in the Leuven region (located in the central, most industrialized part of Belgium). Informed consent was obtained from the parents of 362 children; of these, 81 had to be excluded because of a lack of biometric information (10 children), unavailability at the time of the test (17 children) or failure to perform the test procedure (56 children). Therefore, 281 children, who were examined at the centre between 1 December, 1995 and 20 June, 1996 were included in the study. The relevant items and the scoring system of the standardized questionnaire on the presence of asthma are outlined in table 1. As the questions on wheezing and shortness of breath have proven to be most reproducible [20], these were given the most weight in the interpretat...