Diurnal Variation In Peak Expiratory Flow Research Articles

Short-term exposure to ozone and asthma exacerbation in adults: A longitudinal study in China.

The relationships between short-term ozone exposure and the acute exacerbations of asthma in adults have not been fully studied. Existing studies commonly ignored the effects of ozone on mild or early asthma exacerbations. To investigate the associations between short-term ozone exposure and asthma exacerbations in Chinese adults. We administered health management for adult asthma patients through the Respiratory Home Platform and required them to monitor their lung function every morning and evening by themselves. Finally, a total of 4,467 patients in 18 Chinese cities were included in the current analyses, with 79,217 pairs of lung function records. The maximum daily 8-h average ozone concentrations were collected from fixed-site air quality monitoring stations. We calculated diurnal peak expiratory flow (PEF) variation using morning and evening measurements of PEF and then defined different severity of asthma exacerbations with diurnal PEF variations >10, 15, and 20%, respectively. A binomial distributed generalized additive mixture model combined with distribution non-linear models was applied to examine the association of ozone with asthma exacerbations. We further conducted stratified analyses by sex, age, season of lung function tests, and region. We found that short-term ozone exposure was independently associated with an elevated risk of asthma exacerbations defined by lung function and the effects could last for about 2 days. At lag 0-2 days, each 10 μg/m3 increment in ozone concentration was associated with odds ratios of 1.010 [95% confidence interval (CI): 1.003, 1.017], 1.014 (95% CI: 1.005, 1.023), and 1.017 (95% CI: 1.006, 1.028) for asthma exacerbations that were defined by diurnal PEF variation over 10, 15, and 20%, respectively. The associations remained significant after adjusting for other pollutants, and became unstable when using 24-h average ozone concentration. We also found that the associations were relatively stronger in males, those aged 45 years and older, and in the warm season. Our results suggest that short-term ozone exposure can increase the risk of asthma exacerbations, even in the early stage of exacerbation. Male and older asthma patients may be more vulnerable to ozone air pollution, especially in the warm season.

Cold temperature and sudden temperature drop as novel risk factors of asthma exacerbation: a longitudinal study in 18 Chinese cities

BackgroundFew studies have explored the role of ambient temperature in asthma exacerbation. ObjectiveWe aimed to explore the association of temperature with diurnal peak expiratory flow (PEF) variation and asthma exacerbation. MethodWe developed a longitudinal study among asthmatic adults in 18 Chinese cities. Subjects recorded PEF in dynamic pulmonary function monitoring from 2017 to 2020. Linear mixed-effect model and generalized additive model with distributed non-linear models were used to assess the effect of temperature and temperature change between neighboring days (TCN) on diurnal PEF variation and the risk of asthma exacerbation. ResultWe evaluated a total of 79,217 daily PEF monitoring records from 4467 adult asthmatic patients. There were significant increase of diurnal PEF variation and higher risk of asthma exacerbation with cold and sudden temperature drop. Compared with the referent temperature (99th percentile, 32 °C), exposure to moderate cold (25th percentile, 3 °C) and extreme cold (2.5th percentile, −7 °C) was associated with elevations of 1.28% and 1.16% in diurnal PEF variation over lag 0–2 days, respectively. The odds ratios of asthma exacerbation (determined by diurnal PEF variation >20%) at the two temperature cutoffs were 1.68 and 1.73. A sudden temperature drop (2.5th percentile of TCN, −5 °C) was associated with 1.13% elevation in diurnal PEF variation, and with increased risk of asthma exacerbation (odd ratio = 1.50) over lag 0–4 days. ConclusionThis large multicenter study provided the first-hand empirical evidence that cold temperature and a temperature drop may increase the risk of asthma exacerbation.

Diurnal Variation of Peak Expiratory Flow Rate in Healthy Young Adults of North East of India

PEF measurement is a simple and easy procedure to evaluate and assess the degree of 24hrs variation (circadian) in lung function. Thus this study was undertaken to study the diurnal variation in peak expiratory flow (PEF) in 60 healthy non-smoking adults of Northeast, in the age group between 18-24 years. The PEFR (L/min) was measured with mini Wright’s peak flow meter for three times a day, morning, afternoon and evening. The diurnal variation was observed with lowest values in the morning followed by progressive rise peaking in the evening. Diurnal variation for individual subject was calculated by using amplitude percent mean (A%M). We conclude that a definite pattern of diurnal variation in PEF is seen in healthy population and its knowledge is important for meaningful interpretation of PEF recordings in disease condition.

Cleaning products and short-term respiratory effects among female cleaners with asthma

ObjectiveWe evaluated the short-term effects of exposure to cleaning products on lung function and respiratory symptoms among professional cleaning women.MethodsTwenty-one women with current asthma and employed as professional cleaners participated...

Markers that can Reflect Asthmatic Activity before and after Reduction of Inhaled Corticosteroids: A Pilot Study

Evaluation of airway inflammation is important in achieving adequate dosing of inhaled corticosteroids (ICS) for treating bronchial asthma. However, there is no evaluation tool that can be used in clinical settings. We examined biomarkers that can precisely reflect airway inflammation when ICS are decreased in stable asthmatic patients. This was a 12-week, single-arm, open-label clinical study performed at a single university hospital. Twenty-five patients (6 male and 19 female) with stable asthma were included in this study. We investigated whether the levels of nitrite and nitrate in exhaled breath condensate (EBC) increase after ICS reduction. We also investigated whether blood eosinophils, serum immunoglobulin E (IgE), high-sensitivity C reactive protein (hs-CRP), interleukin (IL)-13, IL-17, and periostin are different before and after ICS reduction. Peak expiratory flow (PEF), pulmonary function tests, asthma control test (ACT), and asthma quality of life questionnaire (AQLQ) were also examined. We considered an unscheduled hospital visit due to asthmatic symptoms and decline in average PEF over one week by more than 10% to indicate disease instability, and compared patients with stable and unstable disease for analysis. Unstable status was detected in 5 patients. Age, sex, asthma duration, ACT and AQLQ scores, and the level of serum IgE did not differ between stable and unstable groups. In the unstable group, the total concentration of nitrite and nitrate at the last visit was 9.84 (6.65–11.24) μM. Surprisingly, this was similar to the concentration at the first visit (5.58 (2.94–17.29) μM). Serum periostin before ICS reduction (141.9 [107.7–147.7] pg/mL) was higher in the unstable group than in the stable group (91.5 [78.75–103.5] pg/mL). The unstable group had a higher peripheral blood eosinophil count and wider diurnal variation of PEF at the first visit compared to the stable group. Higher eosinophils in peripheral blood and wider diurnal variation of PEF were predictive markers for unstable disease after ICS reduction. Serum periostin is another candidate for the predictive marker.

Determinants of asthma control and quality of life in stable asthma: evaluation of two new cough provocation tests

Asthma control and quality of life are poorly associated with traditional asthma biomarkers. In the present study, we evaluated two new cough provocation tests in this respect. Asthma Control Questionnaire and Leicester Cough Questionnaire were completed by 36 stable asthmatics. Cough provocation tests with hypertonic saline and isocapnic hyperpnoea of dry air were performed, as well as spirometry, ambulatory peak expiratory flow (PEF) monitoring and exhaled nitric oxide (eNO) measurement. Leicester Cough Questionnaire score correlated closely with cough responsiveness to hypertonic saline and isocapnic hyperpnoea (R = -0.66, P < 0.001 and R = -0.49, P = 0.002, respectively). Asthma Control Questionnaire score also correlated with the cough responsiveness to these tests (R = 0.52, P = 0.001 and R = 0.43, P = 0.008, respectively). Forced expiratory volume in 1 s (%predicted), diurnal PEF variation and eNO did not correlate with cough-related quality of life but showed some association with asthma control. There was a significant correlation between Leicester Cough Questionnaire and Asthma Control Questionnaire (R = -0.54, P = 0.001). Asthma control and cough-related quality of life are more closely associated with cough responsiveness to the investigated cough provocation tests than to eNO and traditional indices of bronchial obstruction. Cough is a major contributor to poor asthma control.

Comparable effect of a leukotriene receptor antagonist and long-acting beta2-adrenergic agonist in cough variant asthma

Cough variant asthma (CVA) is a common cause of chronic persistent cough, in which allergic airway inflammation may play a role. Although current guidelines recommend bronchodilators and anti-inflammatory drugs for the treatment, comparison of the efficacy of these medications has not been investigated. This study was designed to evaluate the effectiveness of pranlukast, a leukotriene receptor antagonist, and salmeterol, a long-acting beta₂-adrenergic agonist, in the treatment of CVA. The study was a randomized, controlled, parallel-group, multicenter trial. After a 4-week run-in period, 49 patients with newly diagnosed CVA were assigned to receive oral pranlukast (225 mg, b.i.d.) or inhaled salmeterol (100 μg, b.i.d.) for 4 weeks. Primary outcome measure was cough symptom and secondary outcome measures were pulmonary function and eosinophilic airway inflammation. Treatment with pranlukast and salmeterol each decreased cough symptom scores, where the changes from baseline values were significantly greater in the pranlukast group than in the salmeterol group. Forced expiratory volume in 1 second and peak expiratory flow (PEF) increased in the two treatment groups with the same magnitudes, but significant decreases in diurnal variation of PEF and eosinophil counts and eosinophil cationic protein contents in the peripheral blood and induced sputum were observed only in the pranlukast group. In view of antitussive and anti-inflammatory actions, the leukotriene receptor antagonist pranlukast seems to be more effective than the long-acting beta₂-adrenergic agonist salmeterol in the treatment of CVA.

Pulmonary testing using peak flow meters of very low birth weight children born in the perisurfactant era and school controls at age 10 years

We determined lung function at age 10 years in very low birthweight (VLBW, <or=1,500 g) children and controls, and compared the sensitivity to detect subgroup differences by peak expiratory flow (PEF), forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC) and their diurnal variation. VLBW children were recruited across the perisurfactant era at admission to six NICUs in Wisconsin and Iowa, and controls from area classrooms. Two hundred sixty five VLBW children and 360 controls were tested by the Jaeger AM1 peak flow meter at age 10 years. Two hundred six VLBW and 79 controls had additional home monitoring. Abnormality was defined as observed/predicted ratio <0.8 for PEF, FEV(1), and FVC, and by criteria of Pelkonen for diurnal PEF variation. VLBW children were compared to controls, VLBW children with bronchopulmonary dysplasia (BPD) to those without, and those with respiratory conditions to those without. PEF and FEV(1) showed high reproducibility (intraclass correlations, ICC 0.75-0.83). Controls and VLBW children with and without BPD differed significantly on all measures. Baseline test results did not differ across birth years, but PEF variation was less after surfactant availability (P = 0.04). Observed over predicted FEV(1) was the most sensitive in detecting differences between groups (P < 0.001), with mean (s.d.) 0.97 (0.12) for controls, 0.88 (0.14) for VLBW children without BPD, and 0.78 (0.13) for those with BPD. Odds ratios for abnormality were especially high with respiratory medication use during the first 5 years of life, 4.4 (95% CI: 2.0-9.8) for FEV(1) and 5.1 (95% CI: 2.0-13.2) for diurnal PEF variation. Our results show that respiratory abnormalities persist to at least age 10 years for VLBW children born in the surfactant era.

Effect of Fetal Sex on Airway Lability in Pregnant Women With Asthma

An estimated 4% to 8% of pregnant women in the United States have asthma, and there is preliminary (as well as anecdotal) evidence that women bearing a female fetus have more marked symptoms. The authors hypothesized that a female fetus is associated with worse maternal asthma during pregnancy as manifested by greater diurnal variation in peak expiratory flow (PEF)—an accepted marker of the severity of asthma. A protective effect from the androgen surge noted at 12 to 16 weeks gestation when the fetus is male may be part of the explanation. The authors examined this association prospectively in 702 pregnant women diagnosed as asthmatic. They were seen in southern New England in the years 1997–2000. Repeated measurements of expiratory flow lability (percent daily maximum minus the minimum divided by the mean PEF) were made at 21, 29, and 37 weeks gestation. Participants were contacted by phone and asked about symptoms within a month after delivery. The median PEF rate was somewhat higher in women carrying a male rather than a female fetus (378 vs 370 L/minute). Measurements of median diurnal variation in PEF indicated more severe asthma in women bearing a female fetus (8.5% vs 7.8%). In a fully adjusted model, there was a difference of −9.9% in airway lability (95% confidence interval, −19.4 to −0.4) between women carrying a female fetus and those with male fetuses. Greater lability was associated with presence of a female fetus. This difference persisted throughout pregnancy. These findings affirm a correlation between fetal sex and the severity of maternal asthma during pregnancy. Throughout pregnancy, an approximately 10% improvement in airway lability was associated with the presence of a male rather than a female fetus.

Maximal Airway Response to Methacholine in Cough-Variant Asthma: Comparison With Classic Asthma and Its Relationship to Peak Expiratory Flow Variability

<h3>Background:</h3> In asthmatic subjects, not only airway sensitivity but maximal airway response are increased on the dose-response curve to methacholine, and peak expiratory flow (PEF) variability is closely related to airway hypersensitivity and maximal airway response. <h3>Objective:</h3> The aims of this study were to compare the prevalence and the level of maximal response plateau between patients with cough-variant asthma (CVA) and those with classic asthma (CA), and to examine the relationship between airway hypersensitivity or maximal airway response and PEF variability in patients with CVA. <h3>Methods:</h3> A high-dose methacholine inhalation test was performed on 83 patients with CVA and on 83 patients with CA matched for provocative concentration of methacholine causing a 20% fall in FEV₁ (PC₂₀). PEF was recorded in the morning and evening for 14 consecutive days in 78 CVA patients, and the amplitude percentage mean was used to express the diurnal PEF variation. <h3>Results:</h3> Fifty-two CVA subjects (62.7%) but only 33 CA subjects (39.8%) showed a maximal response plateau. This difference was significant after correction by the Bonferroni method (corrected p=0.024). Subjects in the CVA and CA groups showing a plateau had significantly different plateau levels (38.0 ± 5.9% vs 42.9 ± 3.9%, corrected p=1.0 × 10^-4). In patients with CVA, no significant relationship was found between PC₂₀ and PEF variability. However, the absence of a maximal response plateau and a higher plateau level were associated with increased PEF variability. <h3>Conclusions:</h3> Maximal airway response may be an important confounder in the relationship between airway hypersensitivity and the clinical expression of asthma. The identification of a maximal response plateau and the level of this plateau in patients with CVA provide information relevant to PEF variability.

Sensitivity and Validity of Three Bronchial Provocation Tests To Demonstrate the Effect of Inhaled Corticosteroids in Asthma

To compare the sensitivity and validity of mannitol, histamine, and cold air challenges to demonstrate the effect of inhaled corticosteroids (ICS) in asthma. A prospective study. Seventeen patients with recently diagnosed, steroid-naive asthma who fulfilled the diagnostic criteria of Finnish Social Insurance Institution and were hyperresponsive to both mannitol and histamine. The following procedures were carried out at baseline and after 3 months and 6 months of treatment with inhaled budesonide, 800 microg/d: symptom assessment with a questionnaire, ambulatory peak expiratory flow (PEF) measurements twice daily for 2 weeks, and bronchial challenges with mannitol, histamine, and cold air. Budesonide decreased the sum symptom score, daily use of bronchodilating drugs, and diurnal PEF variation, but did not change FEV(1) percentage of predicted significantly. In addition, budesonide significantly decreased mannitol (p = 0.005) and histamine (p = 0.002) response dose ratios. The magnitude of the budesonide-induced change in responsiveness to these two challenges did not differ significantly. The effect of budesonide on cold air responsiveness did not reach statistical significance (p = 0.064). Change in mannitol responsiveness correlated significantly with the changes in sum symptom score and in FEV(1). Change in cold air responsiveness correlated with the changes in sum symptom score and in diurnal PEF variation. Change in histamine responsiveness correlated only with change in FEV(1). Mannitol challenge is both a sensitive and valid test to demonstrate the effects of ICS in asthma. Histamine challenge is equally sensitive for this purpose, but its validity may be lower than that of mannitol challenge. Cold air challenge seems to be a valid test to demonstrate the effects of ICS, but its sensitivity may be lower than that of mannitol and histamine challenges.

Effects of Weight Loss on Peak Flow Variability, Airways Obstruction, and Lung Volumes in Obese Patients With Asthma

To clarify the pathophysiologic features of the relation between asthma and obesity, we measured the effects of weight reduction on peak expiratory flow (PEF) variability and airways obstruction, compared to simultaneous changes in lung volumes and ventilatory mechanics in obese patients with stable asthma. Fourteen obese asthma patients (11 women and 3 men; aged 25 to 62 years) were studied before and after a very-low-calorie-diet period of 8 weeks. PEF variability was determined as diurnal and day-to-day variations. FEV(1) and maximal expiratory flow values were measured with a flow-volume spirometer. Lung volumes, airways resistance (Raw), and specific airways conductance were measured using a constant-volume body plethysmograph. Minute ventilation was monitored in patients in supine and standing positions. As patients decreased their body mass index (SD) from 37.2 (3.7) to 32.1(4.2) kg/m(2) (p < 0. 001), diurnal PEF variation declined from 5.5% (2.4) to 4.5% (1.5) (p = 0.01), and day-to-day variation declined from 5.3% (2.6) to 3. 1% (1.3) (p < 0.005). The mean morning PEF, FEV(1), and FVC increased after weight loss (p = 0.001, p < 0.005, and p < 0.05, respectively). Flow rate at the middle part of FVC (FEF(25-75)) increased even when related to lung volumes (FEF(25-75)/FVC; p < 0. 05). Functional residual capacity and expiratory reserve volume were significantly higher after weight loss (p < 0.05 and p < 0.005, respectively). A significant reduction in Raw was found (p < 0.01). Resting minute ventilation decreased after weight loss (p = 0.01). Weight loss reduces airways obstruction as well as PEF variability in obese patients with asthma. The results suggest that obese patients benefit from weight loss by improved pulmonary mechanics and a better control of airways obstruction.

Effect of a Thromboxane A2 Antagonist on Sputum Production and Its Physicochemical Properties in Patients With Mild to Moderate Asthma

To determine the effects of a specific thromboxane A(2) (TxA(2)) receptor antagonist, seratrodast, on asthma control and airway secretions. Multicenter, double-blind, randomized, placebo-controlled study. Forty-five patients with mild to moderate asthma who had been continuously expectorating sputum of > 20 g/d. Patients with a current pulmonary infection or taking oral corticosteroids, antibiotics, or mucolytic agents were excluded from the trial. Following a 2-week run-in period, while pulmonary function, sputum production, and mucociliary function were assessed, patients were assigned to receive seratrodast, 40 mg/d, or placebo for 6 weeks. During the treatment period, the changes in FEV(1) and peak expiratory flow (PEF) were not different between the two patient groups, but there were significant reductions in diurnal variation of PEF (p = 0.034), frequency of daytime asthma symptoms (p = 0.030), and daytime supplemental use of beta(2)-agonist (p = 0.032) in the seratrodast group. For sputum analysis, seratrodast treatment decreased the amount of sputum (p = 0.005), dynamic viscosity (p = 0. 007), and albumin concentration (p = 0.028), whereas it had no effect on elastic modulus or fucose concentration. Nasal clearance time of a saccharin particle was shortened in the seratrodast group at week 4 (p = 0.031) and week 6 (p = 0.025), compared with the placebo group. Blockade of TxA(2) receptor has minimal effects on pulmonary function, but may cause an improvement in mucociliary clearance by decreasing the viscosity of airway secretions.

Once–Daily Theophylline Reduces Serum Eosinophil Cationic Protein and Eosinophil Levels in Induced Sputum of Asthmatics

Background: Because eosinophilic airway inflammation is a characteristic feature of bronchial asthma, the treatment of airway inflammation is important in the management of asthma. Theophylline has been reported to reduce airway inflammation, in addition to its well–known bronchodilating effect. Objective: In order to evaluate the effects of theophylline on airway inflammation, we investigated 48 subjects with mild and moderate asthma. Methods: The patients were randomly divided into two groups, with or without theophylline treatment (control n = 24; theophylline, n = 24). We examined the level of serum eosinophil cationic protein (ECP), induced sputum samples, and peak expiratory flow (PEF) and obtained spirograms before and after 4 weeks of treatment with once–daily theophylline (200–600 mg/day) of subjects with mild or moderate asthma. Results: Theophylline significantly increased morning and evening PEF and significantly decreased the diurnal variation of PEF. After treatment with theophylline, both serum ECP and the percentage of eosinophils in induced sputum were significantly decreased. In contrast, peripheral blood eosinophil count was unchanged after treatment with theophylline. Conclusions: These findings suggest that theophylline reduces airway inflammation and the severity of asthma, presumably via suppression of both eosinophil activity and subsequent eosinophil infiltration of the airways.

Effect of AA-2414, a thromboxane A 2 receptor antagonist, on airway inflammation in subjects with asthma

Background: Asthma is a chronic inflammatory disease of the airways. The chemokines are potent chemoattractants for eosinophils and other types of cells associated with allergic inflammation. AA-2414, a new thromboxane A 2 receptor antagonist, reduces bronchial hyperresponsiveness in asthmatic subjects, but its mechanism of action is unclear. Objective: We tested the hypothesis that the beneficial effects of AA-2414 in asthma result from reduction in the number of inflammatory cells infiltrating the airway associated with inhibition of chemokine release. Methods: We studied bronchial biopsy specimens from 31 asthmatic subjects before and after oral treatment with AA-2414 (80 mg/day) or matched placebo for 4 months in a double-blind manner. Biopsy specimens were examined by immunohistochemistry. Each subject recorded symptom score and peak expiratory flow (PEF). Lung function and bronchial responsiveness to methacholine were measured before and after treatment. Results: After treatment, significant improvements in symptom score ( P < .05), PEF ( P < .01), diurnal variation of PEF ( P < .01), and bronchial responsiveness ( P < .01) were observed in the AA-2414 group compared with the placebo group. These improvements were accompanied by a significant decrease in the number of submucosal EG2 + eosinophils ( P < .05). There was also a reduction in the number of cells expressing RANTES ( P < .05) and macrophage inflammatory protein (MIP)-1α ( P < .05) in the epithelium and of cells expressing monocyte chemotactic protein-3 ( P < .01), RANTES ( P < .05), MIP-1α ( P < .01), and eotaxin ( P < .01) in the submucosa in the AA-2414 treatment group. A significant correlation was found between the number of EG2 + eosinophils and numbers of monocyte chemotactic protein-3 + ( r s = 0.52, P < .005), MIP-1α + ( r s = 0.34, P < .05), and eotaxin + cells ( r s = 0.47, P < .01) in the submucosa. There was a significant negative correlation between the increase in bronchial responsiveness and the change in number of submucosal EG2 + cells ( r s = –0.65, P < .001). Conclusions: These findings suggest that AA-2414 treatment of patients with asthma may inhibit activated eosinophil infiltration in part by modulating the expression of chemokines in bronchial tissues. (J Allergy Clin Immunol 1999;103:1054-61.)

Effect of inhaled glucocorticoid on the cellular profile and cytokine levels in induced sputum from asthmatic patients.

Cytokines are considered to play a role in the airway inflammation of bronchial asthma. We examined the cellular profile and cytokine levels in induced sputum samples obtained before and after treatment with beclomethasone dipropionate (BDP, 800 microg/day, for 4 weeks) in 12 mild to moderate asthmatic subjects who had not previously received inhaled glucocorticosteroids. Sputum was induced with a 20-min inhalation of 3% saline by an ultrasonic nebulizer. The freshly expectorated sputum separated from the saliva was analyzed for cell counts, for the concentration of interleukin-8 (IL-8), and for the concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF). The mean percentage of eosinophils in the sputum samples decreased significantly after BDP treatment, but no significant change in the percentage of neutrophils was observed. The mean IL-8 and GM-CSF levels also decreased significantly after treatment. The BDP treatment was associated with an increase in the mean peak expiratory flow (PEF) and with a decrease in the diurnal variation of PEF. These results suggest that inhaled steroids improve airway inflammation and lung function in asthmatics, presumably in part by inhibiting the synthesis of inflammatory cytokines such as IL-8 and GM-CSF.

Diurnal Variation of Peak Expiratory Flow in Children with Cough Variant Asthma

Cough variant asthma (CVA) is thought to be a variant form of asthma in which cough is the sole clinical manifestation of airways hyperresponsiveness, a characteristic feature of asthma. Another characteristic feature of asthma includes an increased diurnal variation of peak expiratory flow (PEF) compared to normal subjects. To examine whether diurnal variation of PEF might also increase in children with CVA, we have examined the degree of diurnal variation of PEF in these children (n = 7) by measuring peak flow serially for a week, and compared it with those in mild to moderate asthma (n = 17) and in control children without cough (n = 8). In control children without cough, the average value of the mean diurnal variation of PEF was 10.4 ± 0.8%. In both groups of children with asthma and with CVA, there was a significant increase in the value (20.5 ± 1.3% and 23.6 ± 3.6%, respectively) compared to that in control children (p < 0.01 in both groups), although there was no significant difference between these 2 groups. These results show that mild, but significant airway obstruction is occurring in children with CVA, although clinical wheezing is not recognized. Serial measurements of diurnal variation of PEF may be helpful for the diagnosis of CVA in children.

Bronchial lability and responsiveness in school children born very preterm.

We evaluated bronchial lability and responsiveness in 29 prematurely born children (birth weight < 1,250 g) 8 to 14 yr of age, 12 with histories of bronchopulmonary dysplasia (BPD). Flow-volume spirometry, a bronchodilator test, and histamine challenge at the office and home monitoring of peak expiratory flow (PEF) values twice daily for 4 wk with and without a beta2-agonist were performed with a novel device, the Vitalograph Data Storage Spirometer. The spirometric values at the office and the results of home monitoring were compared with those for a control group of children born at term. All spirometric values except FEV1/FVC were significantly lower in the BPD group than in the non-BPD group (p < 0.0001). Ten children (83%) in the BPD group and four (24%) in the non-BPD group had subnormal spirometric values at the office, indicating bronchial obstruction. Of the children with obstruction, 79% reported respiratory symptoms during the preceding year, and 57% had increased diurnal PEF variation and/or responded to administration of a beta2-agonist during home monitoring or at the office. The BPD children were significantly more responsive to histamine than the non-BPD children (p = 0.002). All spirometric values were significantly lower in both preterm groups than in the control group born at full term (p < 0.01). In conclusion, regardless of BPD, bronchial obstruction, bronchial lability, and increased bronchial responsiveness are common in prematurely born children of school age.

A Two-Month Comparison of Salmeterol/Beclomethasone and Slow-Release Terbutaline/Budesonide in Moderate Asthma Management

The recommendations, according to international guidelines, for moderate asthma poorly controlled by inhaled corticosteroid therapy (800 to 1000 μg/day) — Step Three asthma — is a combination treatment strategy consisting of a longacting bronchodilator plus an inhaled corticosteroid. This comparative multicentre, randomised, open, parallel-group study was designed to compare salmeterol (50μg twice daily) + beclomethasone dipropionate (BDP) [500μg twice daily] (both administered via metered dose inhaler) with slow-release (SR) terbutaline (5mg twice daily) + budesonide (BUD) [400μg twice daily] (administered via tablet and dry powder inhaler, respectively) for the treatment of Step Three asthma. The effects of the two combination regimens were assessed using lung function measurements, asthma symptoms, frequency of use of rescue β2-agonist, overall efficacy, quality of life and tolerability. After a 2-week run-in period, 98 patients were randomised to receive salmeterol/BDP and 96 to receive SR-terbutaline/BUD for 8 weeks. Both treatment arms significantly improved all of the above parameters. However, the improvements observed in the salmeterol/BDP group were significantly better than those in the SR-terbutaline/BUD group for the following parameters: increase in spirometric and homemonitored peak expiratory flow (PEF), reduction in diurnal variation of PEF, reduction in use of daytime salbutamol as rescue medication, patients’ and investigators’ assessment of efficacy, and improvement in quality-of-life score using the Qualite de Vie Subjective de l’Asthmatique questionnaire. Both drug combinations were well tolerated, with slightly fewer patients experiencing treatmentrelated adverse events in the salmeterol/BDP group (9 vs 14%). In conclusion, whilst both combination regimens achieved the goals set out in the management of asthma guidelines for Step Three asthma, greater control of asthma was observed using the salmeterol/BDP combination in this asthmatic patient population.

The etiology and control of bronchial hyperresponsiveness in children.

Bronchial hyperresponsiveness (BHR) describes the exaggerated bronchoconstrictor response to a host of stimuli such as cold air or exercise that occurs in most patients with asthma. It is an important feature of asthma because BHR correlates with diurnal peak expiratory flow variation, bronchospasm following exercise, the need for asthma medications, and asthma severity. Many studies published in the past year have increased our understanding of BHR. First, epidemiologic studies have revealed BHR to be a risk factor for the subsequent development of asthma. BHR is also more common in children than adults, and the persistence of BHR is related to atopy. Second, genetic and pathophysiologic studies have improved our understanding of the etiology of BHR. The genetic basis for BHR, atopy, and asthma was further elucidated with the finding of a cluster of potential candidate genes for asthma susceptibility on chromosome 5. In addition, eosinophilic infiltration and basement membrane thickening of the airways, both characteristic findings noted in patients with asthma, were found to correlate with pulmonary function and degree of BHR. Lastly, studies on treatment of BHR confirmed the beneficial effects of inhaled glucocorticoid therapy and allergen avoidance on BHR in children with asthma. In addition, a new type of asthma medication, the leukotriene inhibitors, has been shown to decrease BHR in adults with asthma and may eventually prove to be an effective medication for children with chronic asthma.