Inaccuracy of portable peak flow meters:correction is not needed

This study examined whether correction of peak expiratory flow (PEF) values for the inaccuracy of the meter would affect asthma management in 102 children (7-14 y old). PEF was recorded with a mini Wright meter twice daily for 2 weeks. As expected, measured PEF overestimated PEF level and asthma control in these children on many diary days. The actual numerical differences between measured and corrected PEF on these days were very small(>5% in only five patients, maximum 10%). It is unlikely that such small changes in PEF justify changes in asthma management, even if these changes cause PEF levels to cross arbitrary borders between various levels of asthma control used in self-management plans. The clinical importance of the inaccuracy of portable PEF meters is negligible

THE EFFECT OF AN INHALED CORTICOSTEROID (BUDESONIDE) ON EXERCISE-INDUCED ASTHMA IN CHILDREN

The effect of long-term treatment with inhaled corticosteroid on exercise-induced asthma (EIA) was studied in 55 children, aged 7-18 yrs (mean 12 yrs). We also compared the time course of stabilization of EIA to that of other indicators of airway responsiveness, such as peak expiratory flow (PEF) variation and the provocation dose of histamine causing a 20% fall in forced expiratory volume in one second (FEV1). All children participated in an ongoing multicentre study to compare the effects of long-term treatment either with the beta2-agonist salbutamol (600 mug.day-1) plus the inhaled corticosteroid budesonide (600 mug.day-1) (BA+CS), or salbutamol plus placebo (BA+PL), on airway calibre, airway responsiveness and symptoms. After a median follow-up of 22 months, the study design had to be changed, because of the high number of drop-outs on BA+PL. At that time, the treatment regimen of all children who had not withdrawn was changed into BA+CS. At the moment of change, and after 2 and 8 months of treatment, a treadmill exercise test was performed in two centres. Eighteen of the 22 children (82%) who were treated with BA+PL from the beginning had EIA, compared to 18 of the 33 children (55%) who were treated with BA-CS (p We conclude that long-term treatment with inhaled corticosteroid reduced the prevalence of EIA by about 33% and the severity by about 50%, and, furthermore, that the various stimuli of airway hyperresponsiveness act through different bronchoconstricting mechanisms

ASSESSMENT OF BRONCHODILATOR RESPONSE IN CHILDREN WITH ASTHMA

The bronchodilator response (BDR) in forced expiratory volume in one second (FEV1) is routinely assessed to estimate the reversibility of airways obstruction. However, there is no consensus on how the BDR should be expressed, and recommendations applying to children are lacking. Similarly, the relationship between BDR and nonspecific bronchial hyperresponsiveness to histamine (BHR) has not been elucidated. These questions were addressed in 116 children, 7-16 yrs of age, with stable after withdrawal of all pulmonary maintenance medication. Inclusion criteria were an initial FEV1 between 55-90% predicted, and/or FEV1/forced vital capacity )FVC) between 50-75%, as well as a fall in FEV1 of 20% or more when challenged with up to 150 mug histamine. The change in FEV1 (DELTAFEV1) 20 min after inhalation of 800 mug salbutamol was expressed in four ways: as an absolute difference (DELTAV1(l)), as a percentage of predicted FEV1 (DELTAFEV1%pred) or initial FEV1 (DELTAFEV1%init), and as a percentage of the deficit in FEV, (DELTAFEV1%(pred-init)). DELTAFEV1%init and DELTAFEV1%pred were not related to age and stature of the children; DELTAFEV1%(pred-init) was related to stature, whilst DELTAFEV1(l) was related to both age and stature. All indices correlated with initial FEV1. However, this is an artefact introduced by relating change to initial value, rather than to the mean of initial and final value. In fact, BDR, expressed as DELTAFEV1%pred, was only slightly greater in children with the lowest initial airway calibre (p=0.08), unlike DELTAFEV1%init. BDR was weakly related to BHR. We conclude that the BDR in children is best expressed as DELTAFEV1%pred, because this is not dependent on age, stature and initial FEV1. In addition, BDR should not be taken as a measure of bronchial responsiveness to bronchoconstricting stimuli

One year treatment with salmeterol compared with beclomethasone in children with asthma

The aim of this study was to compare the effects of salmeterol and beclomethasone on lung function and symptoms in children with mild to moderate asthma. Sixty-seven children not treated with inhaled corticosteroids were randomized in a double-blind parallel study either to salmeterol 50 mu g b.i.d. or beclomethasone 200 mu g b.i.d. After one year, FEV1 significantly increased in the beclomethasone group, whereas in the salmeterol group there was a small reduction. Differences between groups were 14.2% predicted (p <0.0001) and 7.0% predicted (p = 0.007) for pre-and postbronchodilator FEV1 values, respectively. PD20 methacholine decreased by 0.73 DD (p = 0.05) in the salmeterol group and increased by 2.02 DD (p <0.0001) in the beclomethasone group. Morning and evening PEF and symptom scores improved in both groups, although more in the beclomethasone group. Asthma exacerbations, for which prednisolone was needed, were more frequent in the salmeterol group (17 versus two), as were the number of withdrawals due to exacerbations (six versus one). However, growth was significantly slower in the beclomethasone group (-0.28 SDS) compared with that in the salmeterol group (-0.03 SDS) (p = 0.001). We conclude that treatment with a moderate dose of beclomethasone is superior to salmeterol in children with mild to moderate asthma and recommend that salmeterol should not be used as monotherapy

INFLUENCE OF TREATMENT ON PEAK EXPIRATORY FLOW ACID ITS RELATION TO AIRWAY HYPERRESPONSIVENESS AND SYMPTOMS

Background - Despite effective treatments, the morbidity and mortality of obstructive airways disease (asthma and COPD) remains high. Home monitoring of peak expiratory dow (PEF) is increasingly being advocated as an aid to better management of obstructive airways disease. The few available studies describing effects of treatment on the level and variation of PEF have involved relatively small numbers of subjects and did not use control groups. Methods - Patients aged 18-60 years were selected with PC20 less than or equal to 8 mg/ml and FEV(1) Results - Improvements in PEF occurred within the first three months of treatment with BA + CS and was subsequently maintained: the mean (SE) increase in morning PEF was 51 (8) l/min in the BA + CS group compared with no change in the other two groups. Similarly, afternoon PEF increased by 22 (7) l/min. Diurnal variation in PEF (amplitude %mean) decreased from 18.0% to 10.2% in the first three months of treatment with BA + CS. Within-subject relations between changes in diurnal variation in PEF and changes in PC20 were found to be predominantly negative (median rho-0.40) but with a large scatter. Relations between diurnal variation ation in PEF and changes in symptom scores, FEV(1), and bronchodilator response were even weaker. Conclusions - In patients with moderately severe obstructive airways disease, PEF rates and variation are greatly improved by inhaled corticosteroids. Since the relation of diurnal PEF variation with PC20 symptoms, FEV(1), and bronchodilator response were all weak, these markers of disease severity may all provide different information on the actual disease state. PEF measurements should be used in addition to the other markers but not instead of them