Changes In Peak Expiratory Flow Research Articles

Nebulized fluticasone propionate, a viable alternative to systemic route in the management of childhood moderate asthma attack: A double-blind, double-dummy study

BackgroundIn this study, we compared the clinical and immunological efficacy of nebulized corticosteroid (CS) to systemic route during treatment of moderate asthma attack in children. MethodsIn this randomized, placebo-controlled, double-blind, double-dummy, prospective study, 81 children aged 12 months to 16 years experiencing asthma attack randomized into two treatment groups to receive, either; nebulized fluticasone propionate (n = 39, 2000 mcg/day) or oral methylprednisolone (n = 41, 1 mg/kg/day). Pulmonary index scores (PIS) were assessed at admission and at 1st, 4th, 8th, 12th, 24th, 48th hours, as well as, on day 7 and peak expiratory flow (PEF) at baseline and at the 7th day. Daily symptom and medication scores were recorded for all subjects. Immunological studies included phytohemagglutinin induced peripheral blood mononuclear cells culture supernatant for cytokine responses and CD4(+) CD25(+) FOXP3(+) T regulatory cell (T reg) percentage at baseline and day 7. ResultsThe changes in PIS and PEF were similar in both treatment groups, with a significant improvement in both values at the 7th day, when compared to baseline. In both groups, significant reductions in symptom and medication scores were observed during the treatment period with no significant difference between the groups. At day 7 of intervention, phytohemagglutinin induced IL-4 level was significantly decreased only in the nebulized group compared to baseline (p = 0.01). Evaluation of cytokine responses by means of fold increase (stimulated (S)/unstimulated (US) ratio) revealed a significant reduction in IL-4, IL-5 and IL-17 only in nebulized group (p = 0.01, 0.01, 0.02; respectively). The fold increase value of IL-5 was significantly lower at 7th day in nebulized group when compared to systemic one (p = 0.02). At 7th day, although in both treatment groups the percentage of T reg cells was suppressed, it remained significantly higher in the nebule one when compared to systemic route (p = 0.04). ConclusionIn the management of moderate acute asthma attack, nebulized CS (2000 mcg daily) was found to be as effective as systemic route with regard to clinical improvement. In addition, immunological parameters were more in favor of nebulized route which may imply a salutary effect of local CS usage.

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...

Efficacy of idebenone on respiratory function in patients with Duchenne muscular dystrophy not using glucocorticoids (DELOS): a double-blind randomised placebo-controlled phase 3 trial

Cardiorespiratory failure is the leading cause of death in Duchenne muscular dystrophy. Based on preclinical and phase 2 evidence, we assessed the efficacy and safety of idebenone in young patients with Duchenne muscular dystrophy who were not taking concomitant glucocorticoids. In a multicentre phase 3 trial in Belgium, Germany, the Netherlands, Switzerland, France, Sweden, Austria, Italy, Spain, and the USA, patients (age 10-18 years old) with Duchenne muscular dystrophy were randomly assigned in a one-to-one ratio with a central interactive web response system with a permuted block design with four patients per block to receive idebenone (300 mg three times a day) or matching placebo orally for 52 weeks. Study personnel and patients were masked to treatment assignment. The primary endpoint was change in peak expiratory flow (PEF) as percentage predicted (PEF%p) from baseline to week 52, measured with spirometry. Analysis was by intention to treat (ITT) and a modified ITT (mITT), which was prospectively defined to exclude patients with at least 20% difference in the yearly change in PEF%p, measured with hospital-based and weekly home-based spirometry. This study is registered with ClinicalTrials.gov, number NCT01027884. 31 patients in the idebenone group and 33 in the placebo group comprised the ITT population, and 30 and 27 comprised the mITT population. Idebenone significantly attenuated the fall in PEF%p from baseline to week 52 in the mITT (-3·05%p [95% CI -7·08 to 0·97], p=0·134, vs placebo -9·01%p [-13·18 to -4·84], p=0·0001; difference 5·96%p [0·16 to 11·76], p=0·044) and ITT populations (-2·57%p [-6·68 to 1·54], p=0·215, vs -8·84%p [-12·73 to -4·95], p<0·0001; difference 6·27%p [0·61 to 11·93], p=0·031). Idebenone also had a significant effect on PEF (L/min), weekly home-based PEF, FVC, and FEV1. The effect of idebenone on respiratory function outcomes was similar between patients with previous corticosteroid use and steroid-naive patients. Treatment with idebenone was safe and well tolerated with adverse event rates were similar in both groups. Nasopharyngitis and headache were the most common adverse events (idebenone, eight [25%] and six [19%] of 32 patients; placebo, nine [26%] and seven [21%] of 34 patients). Transient and mild diarrhoea was more common in the idebenone group than in the placebo group (eight [25%] vs four [12%] patients). Idebenone reduced the loss of respiratory function and represents a new treatment option for patients with Duchenne muscular dystrophy. Santhera Pharmaceuticals.

Change in peak expiratory flow over time among workers exposed to polyvinyl chloride dust.

To evaluate the variation of peak expiratory flow (PEF) over a working week among non-smoking workers without previous asthma who have been exposed to polyvinyl chloride (PVC) dust. We conducted a cross-sectional study among 42 operators with exposure to PVC dust (filling hoppers to feed extrusion machines) and 23 employees without exposure to PVC dust in a plant producing PVC pipes in West Africa. A pre-tested questionnaire was administered and PEF was measured using a portable peak flow meter after a day off (day 1), on day 3 and at the end of the week (day 6). The two groups did not differ by age or body mass index. Dyspnoea was more prevalent in exposed workers than controls (52% vs. 13%, P = 0.002). PEF decreased more significantly in exposed workers than controls (-8% vs. -3% on day 3 and -10% vs. -5% on day 6, both P = 0.004). The duration of exposure did not affect PEF variability in the exposed groups. The decrease of PEF over the working week in workers exposed to PVC dust is consistent with occupational asthma, although standard measures to diagnose occupational asthma were not used. This result reinforces the need to prevent excessive exposure to PVC dust.

Can serial PEF measurements separate occupational asthma from allergic alveolitis?

Occupational asthma commonly results in work-related changes in serial peak expiratory flow (PEF) measurements. Whether alveolitis can result in similar changes is unknown. To identify differences and similarities of serial PEF between workers with occupational alveolitis and asthma seen during an outbreak investigation in a factory with metal-working fluid exposure. Workers with respiratory symptoms and rest-day improvement were identified by questionnaire. Each was asked to measure PEF 8 times daily for 4 weeks at home and work. Alveolitis was subsequently diagnosed from a validated scoring system including radiological changes, carbon monoxide diffusing capacity, bronchoalveolar lavage and biopsy results. Occupational asthma was confirmed with a positive Oasys score >2.5 and a mean rest-work PEF >16 l/min from serial 2-hourly PEF measurements. The Oasys PEF plotter calculated differences between rest and workdays for mean PEF, diurnal variation and the scores were used to confirm an occupational effect (Oasys, area between curve and time point). Records were compared between the alveolitis group and the group with occupational asthma without alveolitis. Forty workers with occupational asthma and 16 with alveolitis had indistinguishable PEF changes on workdays in terms of magnitude (median reduction 18.5 and 16.1 l/min, respectively) and diurnal variation. Immediate reactions were more common with occupational asthma and late reactions more common with alveolitis. PEF responses to metal-working fluid aerosols do not distinguish occupational asthma from alveolitis except in timing. They can be used to identify the workplace as the cause of asthma and also alveolitis.

Questions and commentary on the article ‘Daily changes of peak expiratory flow and respiratory symptom occurrence around a soy processing factory’

Dear Editor, An interesting article by Heederik D et al. was published in a recent number of Ann Agric Environ Med. (2014, vol. 21, no 1, 5–10) concerning the relationship between, on the one hand, concentration of soy allergens in the proximity of a factory producing soy oil and intensity of respiratory symptoms, daily changes of peak expiratory flow (PEF) and bronchodilator utilization [1]. The authors tested daily changes of PEF, bronchodilator use and respiratory symptoms in two groups of people: those living in the vicinity of the soy oil factory and habitants living in the control area located about 5 km from the factory. They found positive skin prick tests (SPTs) to common allergens among 81% of participants and positive results of SPTs to soy in 11–12% examined people. The authors concluded that sensitization to soy allergen was not increased among the people living in the proximity of the factory; however, the soy-sensitized individuals living in the surroundings of the factory reported more respiratory symptoms, greater bronchodilator utilization, and lower PEF after having been downwind of the factory. Peak expiratory flow measurements, above all, are a useful method of evaluation of asthma control. Daily variability of PEF of more than 20% can be a symptom of pathological bronchial tree hyperresponsiveness (BHR) and bad asthma control [2]. BHR is an individual feature and is not directly correlated with the concentration of aeroallergens. Among people with allergic rhinoconjunctivitis and without bronchial asthma and/or BHR, the daily variability of PEF could be slight and may be comprised in the normal value for healthy people. The authors found positive results of allergic skin prick tests in the majority of participants from both groups (81%). Unfortunately, they did not report the percentage of people with asthma in both groups. This is important information, insofar as, for example, a higher incidence of bronchial asthma and BHR among participants from the study group may have influence on the greater variability of PEF, respiratory symptoms and bronchodilator consumption. Additionally, on the other hand, the lack of people with bronchial asthma in the control group could result in small daily PEF changes, scant other symptoms. It is also worth considering the smoking status of the participants in the statistical analysis. In the study group, the percentage of current smokers was higher than in the control; obviously, tobacco addiction has a significant influence on bronchial hyperresponsiveness and value of spirometric function tests [3].

Peak expiratory flow, breath rate and blood pressure in adults with changes in particulate matter air pollution during the Beijing Olympics: A panel study

ObjectivesThis study aims to examine whether changes in short-term exposures to particulate matter are associated with changes in lung function, breath rate, and blood pressure among healthy adults and whether smoking status modifies the association. MethodsWe took advantage of the artificially controlled changes in air pollution levels that occurred during the 2008 Olympic Games in Beijing, China and conducted a panel study of 201 Beijing residents. Data were collected before, during, and after the Olympics, respectively. Linear mixed-effect models and generalized estimating equation models were used to compare measurements of peak expiratory flow, breath rate and blood pressure across three time points. ResultsThe mean values of peak expiratory flow were 346.0L/min, 399.3L/min, and 364.1L/min over the three study periods. Peak expiratory flow levels increased in 78% of the participants when comparing the during- with pre- Olympics time points, while peak expiratory flow levels decreased in 80% of participants for the post- and during-Olympic periods comparison. In subgroup analyses comparing the during-Olympic to pre-Olympic time points, we found a larger percentage change in peak expiratory flow (+17%) among female, younger and non-smoking participants than among male, elderly and smoking participants (+12%). The percentage of participants with a fast breath rate (>20/min) changed from 9.7% to 4.9% to 30.1% among females, and from 7.9% to 2.6% to 27.3% among males over the three time points. The changes in blood pressure over the three study periods were not very clear, although there is an increase in diastolic pressure and a decrease in pulse pressure among males during the games. ConclusionsThe results suggest that exposure to different air pollution levels has significant effects on respiratory function. Smoking, age and gender appear to modify participants׳ biological response to changes in air quality.

Effect of Inhaled MgSO4 on FEV1 and PEF in Children with Asthma Induced by Acetylcholine: A Randomized Controlled Clinical Trail of 330 Cases

To determine the response of nebulized magnesium sulfate on the lung function of acetylcholine-induced asthma children. Three hundred and thirty children of asthma with positive bronchial provocation test were randomly divided into three groups: magnesium sulfate, albuterol, and a combination of magnesium sulfate and albuterol. Lung function was compared between the three groups. Forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) as percentage over predicted at 10 min and 20 min in albuterol and combination group were significantly improved when compared to magnesium group. The changes in FEV1 and PEF expressed as absolute and percentage over predicted was not statistically significant from baseline to 20 min in magnesium, albuterol, and combination of magnesium sulfate and albuterol. There was no significant adverse effect observed during the present study. Nebulized magnesium sulfate alone has a bronchodilatory effect in Ach-induced asthmatic children. The combination of MgSO4 and albuterol did not has a synergistic effect.

Heliox-driven β2-agonists nebulization for children and adults with acute asthma: a systematic review with meta-analysis

BackgroundThe effect of heliox as a nebulizer β2-agonist driving gas in acute asthma remains controversial. ObjectiveTo perform a systematic review with a meta-analysis of randomized trials designed to evaluate the efficacy of heliox versus oxygen in driving β2-agonist nebulization in patients with acute asthma. MethodsA search was conducted of all randomized controlled trials published before August 2013. Primary outcomes were change in spirometric measurements and severity composite score (pediatric studies); secondary outcomes were hospitalizations and serious adverse effects. ResultsEleven trials from 10 studies (697 participants) met the inclusion criteria (7 included adults and 3 included children). The mean duration of heliox therapy was 120 minutes and the most common helium–oxygen mixture used was 70:30. Patients receiving heliox presented a statistically significant difference for mean percentage of change in peak expiratory flow (17.2%; 95% confidence interval 5.2–29.2, P = .005). Post hoc subgroup analysis showed that patients with severe and very severe asthma showed a significant improvement in peak expiratory flow compared with those with mild to moderate acute asthma. Heliox-driven nebulization also produced significant decreases in the risk of hospitalizations (odds ratio 0.49, 95% confidence interval 0.31–0.79, P = .003) and severity of exacerbations (pediatric studies; standard mean difference −0.74, 95%% confidence interval −1.45 to −0.03, P = .04). There were no group differences for serious adverse effects. ConclusionThis review suggests that heliox benefits in airflow limitation and hospital admissions could be considered clinically significant. Data support the use of heliox as a nebulizing β2-agonist driving gas in the routine care of patients with acute asthma.

Inflammatory response to acute exposure to welding fumes during the working day

To investigate cardiorespiratory and inflammatory responses in male workers following exposure to welding fumes and airborne particles in actual workplace conditions. We measured blood leukocytes and their differential counts, platelet count, hemoglobin, sensitive C-reactive protein, fibrinogen, E-selectin, IL-(interleukin)1β, IL-6, IL-8, tumor necrosis factor alpha (TNF-α) and endothelin-1 in blood samples of twenty workers before and after their working day. We also studied peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), and exhaled nitric oxide (NO). We assessed heart rate variability (HRV) by obtaining 24-hour ambulatory electrocardiograms. The total blood leukocytes and neutrophils increased after the work shift, whereas IL-1β and E-selectin decreased significantly. There were no statistically significant changes in exhaled NO, FEV1, PEF or HRV. Occupational exposure to welding fumes and particles caused a slight, acute inflammatory effect estimated based on the increased values of leukocytes and neutrophils in blood and a decrease in the interleukin 1β and E-selectin values, but no changes in the pulmonary function (exhaled NO, FEV1, PEF) or HRV during the working day were observed.

Emergency department treatment of adults with acute asthma exacerbations: Effect on exhaled nitric oxide levels

Measurement of exhaled nitric oxide levels (eNO) from asthmatic patients is a noninvasive marker of airway inflammation in both adults and children and has been used as an outpatient measure of asthma control. We examined eNO in acute asthma exacerbations and how it is affected by treatment in the emergency department (ED) setting. Both eNO and peak expiratory flow (PEF) rate were measured at arrival and before discharge for adult asthmatic subjects (n = 28) treated for acute exacerbations in the ED at Kings County Hospital Center during spring and fall pollen seasons. Total serum Immunoglobulin E (IgE), peripheral blood leukocyte numbers, and tobacco smoking history were determined. Routine ED treatment included oral prednisone at 60 mg and inhalation of nebulized albuterol and ipratropium. Both PEF (p = 0.0005) and eNO (p < 0.0001) increased after treatment of subjects. Initial eNO was associated with age (p = 0.0004), absolute eosinophil count (p = 0.003), Asthma Control Test (p = 0.004), and Asthma Quality of Life Questionnaire (p = 0.04). Change in pre- versus posttreatment eNO (ΔeNO) was associated with change in PEF (ΔPEF; p < 0.0001). Initial PEF was associated with oxygen saturation (p < 0.0001). ΔPEF was associated with serum IgE levels. ED visit duration was associated with initial PEF (p = 0.0004), ΔeNO (p = 0.004), and number of albuterol treatments (p = 0.001). These associations remained significant in multivariate models that controlled for demographic factors, asthma control, smoking, and measures of inflammation and ventilation. eNO levels increase after ED treatment of acute asthma exacerbations in adults. Improved ventilation may allow for more accurate measurement of NO produced in inflamed airways.

Shift work effects on serial PEF measurements for occupational asthma

Diurnal variation (DV) affects lung function but the changes are thought to be related to sleep patterns rather than time of day. When diagnosing occupational asthma (OA), serial peak expiratory flow (PEF) measurements are the recommended first line investigation, but could be confounded by shift work. The aim of the study was to investigate the effects of shift work on PEF measurements used for diagnosing OA. PEF records containing more than one shift pattern with ≥ 4 days per shift were identified. OA diagnosis was based on an Oasys-2 score ≥ 2.51 and non-OA on having an alternative clinical diagnosis and Oasys-2 score <2.51. The mean area between curves (ABC) score, mean PEF DV and cross-shift PEF changes were calculated for each shift. Records from 123 workers with OA and 69 without OA satisfied inclusion criteria. In the OA group, PEF declined more on afternoon and night shifts than days (P < 0.001). The ABC score was lower in the OA group on night (P < 0.05) and afternoon shifts (P < 0.05) as compared with days, without significant differences in DV. Among those without OA, cross-shift PEF increased more on day shifts (mean + 25 l/min) than afternoon or night shifts (+1 l/min) (P < 0.001). The sensitivity for the ABC score and DV were good and similar across shifts, but specificity was reduced using DV (DV mean 39%; ABC 98%). PEF responses between work and rest show small differences according to shift type. The ABC score has a high sensitivity and specificity for all shifts; differences in DV have lower specificity.

The unique contribution of manual chest compression–vibrations to airflow during physiotherapy in sedated, fully ventilated children*

This study aimed to quantify the specific effects of manual lung inflations with chest compression-vibrations, commonly used to assist airway clearance in ventilated patients. The hypothesis was that force applied during the compressions made a significant additional contribution to increases in peak expiratory flow and expiratory to inspiratory flow ratio over and above that resulting from accompanying increases in inflation volume. Prospective observational study. Cardiac and general pediatric intensive care. Sedated, fully ventilated children. Customized force-sensing mats and a commercial respiratory monitor recorded force and respiration during physiotherapy. Percentage changes in peak expiratory flow, peak expiratory to inspiratory flow ratios, inflation volume, and peak inflation pressure between baseline and manual inflations with and without compression-vibrations were calculated. Analysis of covariance determined the relative contribution of changes in pressure, volume, and force to influence changes in peak expiratory flow and peak expiratory to inspiratory flow ratio. Data from 105 children were analyzed (median age, 1.3 yrs; range, 1 wk to 15.9 yrs). Force during compressions ranged from 15 to 179 N (median, 46 N). Peak expiratory flow increased on average by 76% during compressions compared with baseline ventilation. Increases in peak expiratory flow were significantly related to increases in inflation volume, peak inflation pressure, and force with peak expiratory flow increasing by, on average, 4% for every 10% increase in inflation volume (p < .001), 5% for every 10% increase in peak inflation pressure (p = .005), and 3% for each 10 N of applied force (p < .001). By contrast, increase in peak expiratory to inspiratory flow ratio was only related to applied force with a 4% increase for each 10 N of force (p < .001). These results provide evidence of the unique contribution of compression forces in increasing peak expiratory flow and peak expiratory to inspiratory flow ratio bias over and above that related to accompanying changes from manual hyperinflations. Force generated during compression-vibrations was the single significant factor in multivariable analysis to explain the increases in expiratory flow bias. Such increases in the expiratory bias provide theoretically optimal physiological conditions for cephalad mucus movement in fully ventilated children.

Prolonged Slow Expiration Technique in Infants: Effects on Tidal Volume, Peak Expiratory Flow, and Expiratory Reserve Volume

Prolonged slow expiration (PSE) is a physiotherapy technique often applied in infants to reduce pulmonary obstruction and clear secretions, but there have been few studies of PSE's effects on the respiratory system. To describe PSE's effects on respiratory mechanics in infants. We conducted a cross-sectional study with 18 infants who had histories of recurrent wheezing. The infants were sedated for lung-function testing, which was followed by PSE. The PSE consisted of 3 sequences of prolonged manual thoraco-abdominal compressions during the expiratory phase. We measured peak expiratory flow (PEF), tidal volume (V(T)), and the frequency of sighs during and immediately after PSE. We described the exhaled volume during PSE as a fraction of expiratory reserve volume (%ERV). We quantified ERV with the raised-volume rapid-thoracic-compression technique. The cohort's mean age was 32.2 weeks, and they had an average of 4.8 previous wheezing episodes. During PSE there was significant V(T) reduction (80 ± 17 mL vs 49 ± 11 mL, P < .001), no significant change in PEF (149 ± 32 mL/s vs 150 ± 32 mL/s, P = .54), and more frequent sighs (40% vs 5%, P = .03), compared to immediately after PSE. The exhaled volume increased in each PSE sequence (32 ± 18% of ERV, 41 ± 24% of ERV, and 53 ± 20% of ERV, P = .03). It was possible to confirm and quantify that PSE deflates the lung to ERV. PSE caused no changes in PEF, induced sigh breaths, and decreased V(T), which is probably the main mechanical feature for mucus clearance.

The Effect of Chronic Sputum Production on Respiratory Symptoms in Severe COPD

Background: Chronic sputum production is a significant but variable complaint in COPD; its effect on symptom burden has not been comprehensively described. We sought to characterize the daily burden of chronic sputum production in severe COPD and the phenotype of those with chronic sputum symptoms. Methods: We studied 50 outpatients with severe COPD who used an electronic diary to document peak expiratory flow (PEF) and respiratory symptoms daily for up to 2 years. A sputum index was derived based on complaints of sputum quantity, color, and consistency, and patients were divided into groups based on average daily sputum index (Low, Medium, High). The presence and severity of respiratory symptoms were scored by a novel method using daily changes in symptoms and PEF from baseline and were categorized into mild, moderate, and severe. Percent emphysema was measured using quantitative CT. Results: In the 14,500 observation days, severe symptom days were greater in the Medium and High groups (379/6089, 1609/4091, and 2624/4317 observation days in Low, Medium, and High, p < 0.0001). The same trend was found even when sputum complaints were removed from the symptom severity score. Observed/predicted PEF ratio was lower in the High group (0.56 ± 0.24, 0.55 ± 0.19, and 0.42 ± 0.12 in each group, p < 0.05 for High compared to Medium and Low). Percent emphysema inversely correlated with average sputum index and quantity (r = −0.449 and r = −0.584, respectively, p < 0.05). Conclusions: Increased sputum production in severe COPD is frequently encountered daily and is associated with more respiratory symptoms, worse airflow obstruction, and less emphysema.

Effect of hourly concentration of particulate matter on peak expiratory flow in hospitalized children: A panel study

BackgroundLittle information is available on the possible association between hourly short-term air pollution and peak expiratory flow (PEF) in asthmatic children.MethodsPEF was measured twice daily, from October through December, 2000, in 17 children aged 8 to 15 years hospitalized with severe asthma. A total of 1198 PEF measurements were made at 7 a.m. and 1175 at 7 p.m. Measurements were conducted immediately prior to medication under the guidance of trained nurses. PEF changes were estimated in 10-μg/m3 increments of particulate matter with a 50% cut-off aerodynamic diameter of ≤2.5 μm (PM2.5), with adjustment for sex, age, height, and temperature. Lagged-hour exposures of up to 24 hours were examined.ResultsIncreased 24-hour mean concentration of PM2.5 was associated with a decrease in both morning and evening PEF (-3.0 l/minute; 95%CI: -4.6, -1.4 and -4.4 l/minute; 95%CI: -7.1, -1.7, respectively). In addition, hourly concentrations of PM2.5 and PEF showed a significant association between some lags of PM2.5 and PEF. Effect size was almost -3 l/minute in both morning and evening PEF for an hourly PM2.5 concentration of 10 μg/m3 in several lags. Even after adjustment for other air pollutants, some of the significant associations with PEF remained.ConclusionAmong hospitalized children with severe asthma, increased hourly concentration of PM2.5 was associated with a decrease in PEF.

Influence of leukotriene pathway polymorphisms on clinical responses to montelukast in Japanese patients with asthma

Montelukast, a cysteinyl leukotriene receptor 1 antagonist, is safe and efficacious in patients with asthma. The mechanisms underlying the significant interpatient variability in response to montelukast are not clear but are believed to be, in part, because of genetic variability. To examine the associations between polymorphisms in candidate genes in the leukotriene pathway and outcomes in patients with asthma on montelukast for 4-8 weeks, we evaluated the changes in peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV(1·0) ) and patients' subjective symptom before and after montelukast treatment. DNA was collected from 252 Japanese participants. Two single-nucleotide polymorphisms (SNPs) in the ALOX5 (rs2115819) and LTA4H (rs2660845) genes were successfully typed. There was no difference between members of the general population (n = 200) and patients (n = 52) in each genotype frequency. Significant associations were found between SNP genotypes in the LTA4H gene and changes in PEF and FEV(1·0) . The PEF and FEV(1·0) responses to montelukast in the A/A genotypes (n = 4) for the LTA4H SNP were significantly higher than those in the G allele carriers (A/G+G/G) (n = 17). Despite the small sample size, our results suggest that genetic variation in leukotriene pathway candidate genes contributes to variability in clinical responses to montelukast in Japanese patients with asthma.

Effects of montelukast on patients with asthma after experimental inoculation with human rhinovirus 16

<h3>Background</h3> Leukotrienes are induced by viral infections. <h3>Objectives</h3> To determine whether treatment with montelukast would improve asthma disease control in patients with mild allergic asthma during an experimentally induced rhinovirus infection. <h3>Methods</h3> Patients with mild allergic asthma were randomized to receive treatment with either montelukast or placebo, and 7 days later both groups were inoculated with human rhinovirus 16. Patients were evaluated at baseline, during the acute infection phase, and during the recovery phase for asthma and cold symptoms by questionnaire. Sputum, nasal lavage fluid, and blood were analyzed for viral shedding and cellular inflammation, and peak expiratory flow was measured daily. <h3>Results</h3> A total of 19 patients (11 in the placebo group and 8 in the active group) completed the study. No significant differences were found in asthma control and cold symptom scores between the control and treatment groups. The change in peak expiratory flow from the randomization to acute illness phase was greater in the placebo group than the treatment group (mean, −22 vs 0 L/min; <i>P</i> = .05). During the recovery phase, the percentage of sputum eosinophils increased in the placebo group and remained at baseline levels in the montelukast group (median, 2.7% vs 0.2%; <i>P</i> = .05 between groups). <h3>Conclusions</h3> In this pilot study, montelukast did not improve asthma control or cold symptom scores caused by experimental rhinovirus infection. Analysis of secondary outcomes suggests that montelukast may prevent reductions in lung function and increases in sputum eosinophils caused by common cold infections. Further studies are needed to determine whether these effects are associated with clinically significant improvements in health outcomes during natural colds. <h3>Trial Registration</h3> clinicaltrials.gov Identifier: NCT00359073.

S160 The effect of shift work on serial peak expiratory flow measurements used to diagnose occupational asthma

We investigated the effects of shift work on Peak Expiratory Flow (PEF) measurements used for diagnosing occupational asthma (OA). In a clinic database of workers investigated for OA, 123 workers...

Cement dust exposure and acute lung function: A cross shift study

BackgroundFew studies have been carried out on acute effects of cement dust exposure. This study is conducted to investigate the associations between current "total" dust exposure and acute respiratory symptoms and respiratory function among cement factory workers.MethodsA combined cross-sectional and cross-shift study was conducted in Dire Dawa cement factory in Ethiopia. 40 exposed production workers from the crusher and packing sections and 20 controls from the guards were included. Personal "total" dust was measured in the workers' breathing zone and peak expiratory flow (PEF) was measured for all selected workers before and after the shift. When the day shift ended, the acute respiratory symptoms experienced were scored and recorded on a five-point Likert scale using a modified respiratory symptom score questionnaire.ResultsThe highest geometric mean dust exposure was found in the crusher section (38.6 mg/m3) followed by the packing section (18.5 mg/m3) and the guards (0.4 mg/m3). The highest prevalence of respiratory symptoms for the high exposed workers was stuffy nose (85%) followed by shortness of breath (47%) and "sneezing" (45%). PEF decreased significantly across the shift in the high exposed group. Multiple linear regression showed a significant negative association between the percentage cross-shift change in PEF and total dust exposure. The number of years of work in high-exposure sections and current smoking were also associated with cross-shift decrease in PEF.ConclusionsTotal cement dust exposure was related to acute respiratory symptoms and acute ventilatory effects. Implementing measures to control dust and providing adequate personal respiratory protective equipment for the production workers are highly recommended.