Difference In Peak Expiratory Flow Research Articles

Impact of sex on severe asthma: a cross-sectional retrospective analysis of UK primary and specialist care

IntroductionAfter puberty, females are more likely to develop asthma and in a more severe form than males. The associations between asthma and sex are complex with multiple intrinsic and external...

World Trade Center workers with asthma and post-traumatic stress disorder perceive airflow limitation more accurately

BackgroundPost-traumatic stress disorder (PTSD) is a major risk factor for increased asthma morbidity among World Trade Center (WTC) workers. ObjectiveTo investigate whether differences in perception of airflow limitation mediate the association of PTSD with worse asthma control in WTC workers. MethodsWe collected data from WTC workers on asthma control (Asthma Control Questionnaire and Asthma Quality of Life Questionnaire) and daily peak expiratory flow (PEF) measures over 6 weeks. Perception of airway limitation was assessed by comparing guessed vs actual PEF values. Post-traumatic stress disorder was diagnosed using the Structured Clinical Interview. We used unadjusted and adjusted models to compare PEF and perception measures in WTC workers with PTSD with those of workers without PTSD. ResultsOverall, 25% of 224 participants had PTSD. Post-traumatic stress disorder was associated with worse Asthma Control Questionnaire (2.2±0.8 vs 1.1±0.9, P < .001) and Asthma Quality of Life Questionnaire (3.9±1.1 vs 5.4±1.1, P < .001) scores. Adjusted analyses showed no significant differences in PEF between WTC workers with (351.9±143.3 L/min) and those without PTSD (364.6±131.6 L/min, P = .55). World Trade Center workers with PTSD vs those without PTSD had increased proportion of accurate perception (67.0±37.2% vs 53.5±38.1%, P = .01) and decreased underperception (23.3.0±32.1% vs 38.9±37.5%, P = .004) of airflow limitation during periods of limitation. Similar results were obtained in adjusted analyses. ConclusionThis study indicates that differences in perception of airflow limitation may mediate the relationship of PTSD and increased asthma symptoms, given WTC workers with PTSD have worse self-reported asthma control, an increased proportion of accurate perception, and decreased underperception, despite no differences in daily PEF measures.

Spirometry in laryngotracheal stenosis: a systematic review and meta-analysis.

This study aimed to assess the changes in spirometry parameters or indices after relieving laryngotracheal stenosis (LTS) in adult patients. A systematic review and meta-analysis of studies from PubMed, Scopus, Web of Science, Cochrane Library, and EBSCO databases was conducted for assessing changes in spirometry values after endoscopic balloon dilatation of LTS in adults. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Relevant data, such as changes in mean spirometry values between preoperative and postoperative interventions, and findings of receiver operating characteristic curve analyses for predicting the need for surgical intervention, were extracted. Ten studies including 330 patients overall met the inclusion criteria. Significant improvements were observed from preoperative to postoperative mean values of different spirometry parameters and indices. The overall mean differences in peak expiratory flow (ΔPEF), expiratory disproportion index (ΔEDI), and peak inspiratory flow (ΔPIF) were 2.26 L/s (95% CI 2.14-2.38), 27.94s (95% CI 26.36-29.52), and 1.21 L/s (95% CI 0.95-1.47), respectively. ΔPEF and ΔPIF values increased, while ΔEDI decreased. In predicting the need for surgical intervention, EDI had the highest sensitivity (88%), and forced expiratory volume per second/forced vital capacity had the highest specificity (85%). Spirometry is a valuable tool for assessing patients with LTS. PEF, EDI, and PIF were the most commonly reported spirometry parameters that significantly improved after airway stenosis was relieved.

Natural history of respiratory muscle strength in spinal muscular atrophy: a prospective national cohort study

BackgroundRespiratory complications are the most important cause of morbidity and mortality in spinal muscular atrophy (SMA). Respiratory muscle weakness results in impaired cough, recurrent respiratory tract infections and eventually can cause respiratory failure. We assessed longitudinal patterns of respiratory muscle strength in a national cohort of treatment-naïve children and adults with SMA, hypothesizing a continued decline throughout life.MethodsWe measured maximal expiratory and inspiratory pressure (PEmax and PImax), Sniff Nasal inspiratory pressure (SNIP), peak expiratory flow (PEF), and peak cough flow (PCF) in treatment-naïve patients with SMA. We used mixed-models to analyze natural history patterns.ResultsWe included 2172 measurements of respiratory muscle function from 80 treatment-naïve patients with SMA types 1c-3b. All outcomes were lower in the more severe phenotypes. Significant differences in PEF were present between SMA types from early ages onwards. PEF decline was linear (1–2%/year). PEF reached values below 80% during early childhood in types 1c-2, and during adolescence in type 3a. PEmax and PImax were severely lowered in most patients throughout life, with PEmax values abnormally low (i.e. < 80 cmH2O) in virtually all patients. The PEmax/PImax ratio was < 1 throughout life in all SMA types, indicating that expiratory muscles were most affected. All but SMA type 3b patients had a lowered PCF. Patients with types 2b and 3a had PCF levels between 160 and 270 L/min, those with type 2a around 160 L/min and patients with type 1c well below 160 L/min. Finally, SNIP was low in nearly all patients, most pronounced in more severely affected patients.ConclusionsThere are clear differences in respiratory muscle strength and its progressive decline between SMA types. We observed lower outcomes in more severe SMA types. Particularly PEF may be a suitable outcome measure for the follow-up of respiratory strength in patients with SMA. PEF declines in a rather linear pattern in all SMA types, with clear differences at baseline. These natural history data may serve as a reference for longer-term treatment efficacy assessments.

The Effect of Participation in Educational Games Activity on Respiratory Values and Anthropometric Properties in Children

Aim: In this study, it was aimed to examine the anthropometric properties and respiratory parameter values of students between the ages of 10-11 who regularly participate in educational games. Methods: 34 students studying, İncesu Kızılören Parlaklar Secondary School, voluntarily participated in the study. While the experimental group (n=18) participated in educational game activities three days a week along with physical education lessons for five weeks, the control group (n=16) attended only physical education lessons. They did not participate in the educational game activities. Two measurements were carried out to the students as pre-test and post-test. Results: While the anthropometric measurements of the students participating in the study were measured with the Tanita measuring device, their respiration values were determined with a spirometer. Data are shown as arithmetic mean and standard deviation. A dependent sample t-test was used to compare independent groups and also paired sample t-test was used to compare dependent groups. The significance level was determined as (p&lt;0.05). In the study, it was seen that there was a significant difference in body fat mass, lean body mass (FFM), total body fluid (ibw) values of the experimental group (p&lt;0.05), while only a significant difference was found in basal metabolic rate (bmh) values in the control group. In the respiratory function values, the forced vital capacity (fvc), the air volume removed in the first second of forced expiration (fev1) of the experimental group. While the difference in peak expiratory flow (pef) and maximum voluntary ventilation (mvv) values were found to be significant, fev1, pef, and mvv values were found to be significant in the control group (p&lt;0.05). Conclusion: It was seen that educational games had a positive effect on anthropometric measurement and respiration values in primary school students aged 10-11 years. We think that increasing the time of the physical education lessons and sparing more time to educational games, explaining the importance of educational games to physical education teachers, school administration, and students, and regular educational game competitions will make a significant contribution to the development of children. Keywords: Educational Games, Anthropometric Measurement, Respiratory

Effects of Spine Mobilization on Cobb’s Angle and Respiratory Function in Patients with Adolescent Idiopathic Scoliosis

Background: Incorrect postures of adolescents caused by the use of smart devices have been noted as a factor causing spinal diseases.Objectives: To examine the effect of joint mobilization and stretching on Cobb’s angle and respiratory function in adolescent idiopathic scoliosis (AIS).Design: Cluster-randomized controlled trial.Methods: A total of 22 subjects with AIS were enrolled. They were allocated to two groups: the joint mobilization (n=11) and the stretching (n=11). All interventions were conducted for 30 minutes, three times a week for six weeks. Outcome measures were the Cobb’s angle and respiratory function. The Cobb’s angle and respiratory function measured using the X-ray and Micro- Quark.Results: Joint mobilization group showed significant differences in Cobb’s angle and respiratory function, but stretching group showed significant differences Cobb’s angle. The differences in peak expiratory flow (PEF) between the two groups were significant.Conclusion: This study proved that joint mobilization is a more effective intervention for AIS to improve Cobb’s angle and respiratory function, when compared to stretching.

Pengaruh Incorporating Progressive Muscle Relaxation dan Diaphragm Breathing Exercise terhadap Aliran Puncak Ekspirasi Pasien Asma

adalah suatu kelainan berupa inflamasi kronik saluran napas yang mengakibatkan penyempitan saluran napas, sehingga meningkatkan resistensi aliran udara dan menurunkan laju aliran ekspirasi. Selain terapi farmakologis, penatalaksanaan asma juga dapat dilakukan secara non farmakologis, diantaranya dengan latihan incorporating progressive muscle relaxation dan diaphragm breathing exercise yang dapat meningkatkan aliran puncak ekspirasi. Tujuan penelitian ini adalah untuk mengetahui pengaruh incorporating progressive muscle relaxation dan diaphragm breathing exercise terhadap peningkatan aliran puncak ekspirasi (APE) pasien asma. Metode penelitian adalah quasy experimental pre-test dan post-test with control group. Jumlah responden penelitian adalah 80 orang yang dibagi menjadi 2 kelompok yaitu 60 orang kelompok intervensi dan 20 orang kelompok kontrol. Hasil uji beda paired sample t-test pada kelompok intervensi menunjukkan perbedaan yang signifikan APE sebelum dan sesudah intervensi (65,05% vs 81,17%, p=0,00). Hasil uji independen t-test menunjukkan perbedaan yang signifikan APE kelompok intervensi dengan kelompok kontrol (81,17% vs 65,10%, p=0,00). Penelitian ini menyimpulkan bahwa latihan incorporating progressive muscle relaxation dan diaphragm breathing exercise berpengaruh pada peningkatan APE.

Peak expiratory flow in the standing and sitting positions is equivalent in adults: a cross-over study.

It is uncertain whether peak flow measurement is best done in the standing or sitting position. In this cross-over study, study participants were randomized to perform the initial peak expiratory flow (PEF) measurement in either standing or sitting position. The highest of three readings in each position were compared using paired t-test. A mean difference of <±25 l/min was set as the equivalence limits. Test of equivalence of standing and sitting PEF measurements was done using MedCalc Software. Test of agreement of standing and sitting PEF was assessed by Lin's concordance correlation coefficient and Bland-Altman limits of agreement. Of the 100 study participants, 50% of them had asthma. There was a statistically significant difference between the standing and sitting PEF in adults suffering from asthma [mean difference 11 l/min, 95% confidence interval (CI) = 4 to 19], but not in the healthy individuals (mean difference 3 l/min, 95% CI = -6 to 12). The observed differences in PEF were small and may not be clinically important. In adults with and without asthma, the standing and sitting PEF were highly correlated and satisfied the test of equivalence. The PEF in the standing and sitting positions was equivalent in adults. Therefore, performing PEF in either position is acceptable. However, health care practitioners should be aware of the small reduction in PEF when it is done in the sitting position. It is desirable that the position used is documented and the same position is used wherever possible.

Montelukast Treatment of Acute Asthma Exacerbations in Children Aged 2 to 5 Years: A Randomized, Double-Blind, Placebo-Controlled Trial.

Although montelukast has an established role in the management of chronic asthma in children, its efficacy in acute asthma exacerbations (AAEs) in children aged 2 to 5 years is not fully known. This study aimed to evaluate the effectiveness and safety of montelukast for treating AAE in children aged 2 to 5 years in China. In total, 120 Chinese children with AAE, aged 2 to 5 years, were randomly divided into 2 groups, each with 60 patients. All patients received either montelukast or placebo along with standard therapy for acute asthma between January 2011 and December 2015. The outcome measurements included the difference in peak expiratory flow and lung function improvements, as well as adverse events. A total of 117 patients completed the study. Montelukast showed no greater effectiveness than did placebo in increasing the peak expiratory flow during the period of hospital stay (P = 0.92 at day 2, P = 0.86 at day 3, and P = 0.82 at day 4) and at discharge (P = 0.84). Similarly, the forced expiratory volume in 1 second at discharge also did not show significant difference between the 2 groups (P = 0.80). In addition, no serious adverse events were found during the intervention period of the study. The results of this study demonstrate no benefit of montelukast over placebo in the treatment of AAE in a cohort of 2- to 5-year-old children.

The efficacy of nebulized magnesium sulfate alone and in combination with salbutamol in acute asthma.

ObjectiveEvaluation of the efficacy of nebulized magnesium sulfate (MgSO4) alone and in combination with salbutamol in acute asthma.MethodsA double-blind randomized controlled study was conducted in Chest and Emergency Departments. Thirty patients of acute attack of bronchial asthma were randomized into three groups: MgSO4 nebulization (group A), salbutamol nebulization (group B), and their combination (group C). All patients were monitored before and after nebulization (each 20 minutes) for peak expiratory flow rate (PEFR), respiratory rate (RR), heart rate (HR), blood pressure, pulsus paradoxus, oxygen saturation, clinical examination, and Fischl index.ResultsA highly significant improvement in PEFR, PEFR percentage, and Fischl index and significant decrease in RR and HR was observed in all groups. A similar improvement in PEFR was observed in group A and group B (P=0.389). The difference in peak expiratory flow (PEF) improvement was insignificant between group B and group C (P=0.101), while there was a significant difference between group A and group C (P=0.014) in favor of group C.ConclusionNebulized MgSO4 alone or combined with salbutamol has a clinically significant bronchodilator effect in acute asthma and leads to clinical improvement, increase in PEFR, reduction in HR, and reduction in RR. The response to nebulized MgSO4 alone (PEFR improvement 54±35.6 L/min, P=0.001) is comparable (P=0.389) to that of nebulized salbutamol (PEFR improvement 67.0±41.9 L/min, P=0.001) and is significantly less than (P=0.014) that of nebulized combination (PEFR improvement 92.0±26.9 L/min, P=0.000).

GENETIC INTERACTIONS BETWEEN ADRB2 AND PTGER4 ON RESPONSES TO SALMETEROL OR MONTELUKAST IN JAPANESE PATIENTS WITH MILD PERSISTENT ASTHMA.

Long-acting β2-agonists (LABA) and leukotriene receptor antagonists (LTRA) are two principal agents that can be added to inhaled corticosteroids (ICS) for patients with asthma that is not adequately controlled by ICS alone. In our previous study, the Gly16Arg genotype of the β2-adrenergic receptor (ADRB2) gene did not influence the differential bronchodilator effect of salmeterol versus montelukast as an add-on therapy to ICS within 16 weeks of follow-up (the J-Blossom study). We examined if genes encoding CYSLTR1, CYSLTR2, PTGER2 or PTGER4 could explain differential responses to salmeterol versus montelukast using the participants of the J-Blossom study. This study included 76 patients with mild-to-moderate asthma. The difference in peak expiratory flow (PEF) (ΔPEF, l/min) after 16 weeks of treatment with salmeterol (ΔPEFsal) versus montelukast (ΔPEFmon) was associated with the genotypes at each of 4 genes. In addition, multivariate analyses were used to identify a gene-gene interaction between ADRB2 gene and each of these 4 genes. Although none of 4 genes were associated with ΔPEFsal-ΔPEFmon in the univariate analyses, multivariate analysis showed that PTGER4 gene, interacting with ADRB2 Gly16Arg, was associated with ΔPEFsal-ΔPEFmon (p=0.0032). Our findings suggested that the interactions between two genetic loci at ADRB2 and PTGER4 is important in determining the differential response to salmeterol versus montelukast in patients with chronic adult asthma.

The effects of a Gly16Arg ADRB2 polymorphism on responses to salmeterol or montelukast in Japanese patients with mild persistent asthma

Long-acting β2-agonists and leukotriene receptor antagonists are two principal agents that can be added to inhaled corticosteroids (ICS) for patients with asthma that is not adequately controlled by ICS alone. The Gly16Arg genotype of the β2-adrenergic receptor (ADRB2) gene may influence the bronchodilator effects of β2-agonists. We hypothesized that differential responses to long-acting β2-agonists or leukotriene receptor antagonists might be determined partly by the Gly16Arg polymorphism in Japanese asthma patients. This randomized, genotype-stratified, two-period crossover study included 80 patients with mild-to-moderate asthma (35 Arg/Arg and 45 Gly/Gly individuals). The primary study outcome was the difference in peak expiratory flow (ΔPEF) (ΔPEF, l/min) by genotype after 16 weeks of treatment with salmeterol (ΔPEFsal) or montelukast (ΔPEFmon). In addition, multivariate analyses were used to identify independent factors that were predictive of responses to each treatment. The mean ΔPEFsal-ΔPEFmon was 19.3±46.6 among Arg/Arg individuals and 16.8±51.5 among Gly/Gly individuals, indicating that the Gly16Arg genotype did not influence the differential bronchodilator effect of the two agents. Multivariate analysis showed that higher peripheral eosinophil counts were associated with better response to salmeterol (P<0.05). The Gly16Arg genotype did not influence the differential bronchodilator effect of salmeterol or montelukast as an add-on therapy to ICS within 16 weeks of follow-up. Higher peripheral eosinophil counts may be associated with better responses to salmeterol in combination with ICS.

Decreased peak expiratory flow in pediatric passive smokers

Background Indonesia ranks fifth among countries with the highest aggregate levels of tobacco consumption in the world. Infants and children exposed to environmental tobacco smoke have increased rates of asthma, respiratory and ear infections, as well as reduced lung function. The effects of tobacco smoke exposure on lung function in children have been reported to be dependent on the source of smoke and the length and dose of exposure. Lung function may also be affected by a child’s gender and asthma status.Objective To compare peak expiratory flow (PEF) in pediatric passive smokers to that of children not exposed to second hand smoke, and to define factors that may affect PEF in passive smokers.Methods In August 2009 we conducted a cross-sectional study at an elementary school in the Langkat district. Subjects were aged 6 to 12 years, and divided into two groups: passive smokers and those not exposed to secondhand smoke. Subjects’ PEFs were measured with a Mini-Wright peak flow meter. Measurements were performed in triplicate with the highest value recorded as the PEF. Demographic data including age, sex, weight, height, family income, parental education levels and occupations were obtained through questionnaires.Results Of the 170 participants, 100 were passive smokers and 70 were not exposed to secondhand smoke. Age distribution, weight and height were similar in both groups. We observed a significant difference in PEFs between the group of passive smokers and the group not exposed to secondhand smoke, 211.3 L/minute (SD 61.08) and 242.7 L/minute (SD 77.09), respectively (P &lt; 0.005). The number of years of exposure to smoke (P = 0.079) and the number of cigarettes smoked daily in the household (P = 0.098) did not significantly influence PEF.Conclusion The PEF in pediatric passive smokers was significantly lower than that of children not exposed to secondhand smoke. PEF in passive smokers was not influenced by the number of years of smoke exposure or the number of cigarettes smoked daily in the household.

Oral montelukast in acute asthma exacerbations: a randomised, double-blind, placebo-controlled trial

BackgroundAlthough leukotriene receptor antagonists have an established role in the management of patients with chronic asthma, their efficacy in an acute asthma exacerbation is not fully known.Methods87 adults with acute...

Peak expiratory flow in Afro‐Caribbean children with and without sickle cell anaemia

To create a reference range of peak expiratory flow (PEF) results of Afro-Caribbean children and determine whether interpretation of PEF results in children with sickle cell anaemia (SCA) differed according to whether comparison was made of results obtained from children of similar age or height. A prospective observational study was carried out in two specialist sickle cell disease clinics. Seventy-eight nonasthmatic African and Caribbean (AC) controls (age range 2.6-17.8 years), and 99 nonasthmatic SCA children (age range 3.4-17.3 years) were recruited. PEF was measured using a dry rolling sealed spirometer before and after bronchodilator therapy. PEF results in the AC controls correlated with height (r = 0.88, p< 0.0001). Comparison of similarly aged children demonstrated that pre- (p = 0.02) and post- (p = 0.04) bronchodilator PEF results were lower in the SCA children, but comparison of children of similar height revealed no statistically significant differences in PEF results between children with SCA and controls. The SCA children tended to be shorter than the controls. The results suggest PEF measurements are not a useful method of monitoring the respiratory status of children with sickle cell disease.

Efficacy and tolerability of beclomethasone dipropionate delivered by a novel multidose dry powder inhaler (Clickhaler ®) versus a metered-dose inhaler in children with asthma

Background: Dry powder inhalers (DPIs) overcome the problem of actuation-breath coordination experienced by many children who use metered-dose inhalers (MDIs). To ensure that therapeutic effectiveness is maintained when switching from 1 inhaler type to another, it is necessary to investigate their clinical comparability. Objective: The purpose of this study was to compare the efficacy and tolerability of beclomethasone dipropionate (BDP) delivered from a novel multidose DPI (Clickhaler ®) versus a conventional MDI plus spacer in children with asthma, and to assess patient acceptability and ease of use of the inhaler devices. Methods: After a 2-week run-in period, children aged 6 to 17 years with mild to moderate asthma were randomly assigned to 4 weeks' treatment with BDP (≤400 μg/d), delivered via Clickhaler or MDI plus spacer, in a double-blind, double-dummy, parallel-group, multicenter study. Efficacy was measured primarily by changes from baseline in morning peak expiratory flow (PEF). Secondary measures were changes in evening PEF, daytime and nighttime asthma symptom scores, and clinic lung function. The statistical power to detect a difference in PEF of 20 L/min was 92%. Results: A total of 124 patients were randomized to treatment (61 to DPI and 63 to MDI plus spacer); 110 patients completed the study. There were no significant differences between the treatment groups in any efficacy parameter ( P > 0.1). The mean ± SD difference between treatments in morning PEF was 2.1 ± 24.2 L/min (95% CI, −6.9 to 11.0; P = 0.35). A total of 37 patients (30%) experienced 72 adverse events, the majority of which were mild. The most commonly reported adverse events were exacerbated asthma, upper and lower respiratory tract infections, sore throat, and cough. The Clickhaler was preferred to the MDI by 76% of patients. Conclusions: BDP delivered by Clickhaler was a well-tolerated and therapeutically equivalent alternative to BDP delivered by a conventional MDI plus spacer in the short-term treatment of mild to moderate asthma in children. The Clickhaler DPI was well accepted in this population and preferred to the MDI.

Efficacy of adding multiple doses of oxitropium bromide to salbutamol delivered by means of a metered-dose inhaler with a spacer device in adults with acute severe asthma

Background: The efficacy of combination therapy adding multiple doses of anticholinergics to β2-agonists to improve outcome has not been established in adults with acute severe asthma. Objective: This study was undertaken to compare the outcome of adults with acute severe asthma treated with 4 puffs of salbutamol (100 μg/actuation) every 20 minutes for 3 doses plus 4 puffs of oxitropium bromide (100 μg/actuation) with each of the 3 salbutamol doses versus salbutamol alone administered by means of a metered-dose inhaler with a spacer device. Methods: A randomized, single-blind, placebo-controlled study was performed in 74 patients between 18 and 55 years old presenting to the emergency department (ED) for treatment of acute asthma with a peak expiratory flow (PEF) of 50% or less than the normal predicted value. The primary endpoint was improvement in PEF over the course. The secondary endpoint was the need for additional ED treatment at 120 minutes. Results: The increase in PEF over the course was significantly greater in the oxitropium plus salbutamol treatment group (P < .0001). The mean absolute difference in PEF at 120 minutes for combination therapy compared with salbutamol alone was 37.8 L/min (P = .001). In addition, the proportion of need for additional ED treatment was less in the combination group than the group receiving salbutamol alone (odds ratio, 0.32; 95% confidence interval, 0.11-0.90). Conclusion: Adding multiple doses of oxitropium bromide to salbutamol delivered by means of a metered-dose inhaler with a spacer device for acute severe asthma produces a significant improvement in lung function and reduces the need for additional ED treatment. (J Allergy Clin Immunol 2000;106:472-8.)

Work-related changes in peak expiratory flow among laboratory animal workers.

Laboratory animal workers are at risk of developing allergic symptoms, of which asthmatic symptoms are the most severe. The aim was to study the relationship between allergic symptoms due to working with rats and variability and changes in peak expiratory flow (PEF). Several indices were used on the basis of the amplitude of the PEF or the differences in PEF between days with and without exposure to rat aeroallergens. Of the 398 rat workers, 73% completed PEF readings on at least 9 days, of whom 208 had PEF readings on working days with and without contact with animals. The overall prevalence rate of allergic symptoms (asthmatic, eye, nose and/or skin) among rat workers during the handling of rats was 17.3%. Asthmatic symptoms were reported by 6.7%. The PEF of the workers who reported asthmatic symptoms due to working with rats decreased significantly on days working with the animals (difference between the minimum PEF averaged over working days with animals and over days without animals (deltaPEFmin-min) = -73 L x min(-1)), compared to the workers without symptoms (2.2 L x min(-1)). This effect was more pronounced among workers with a late asthmatic response, i.e. the presence of asthmatic symptoms several hours after working with rats (deltaPEFmin-min = -11.6 L x min(-1)). Multiple regression analyses showed that only those with asthmatic symptoms several hours after working with rats and those with allergic symptoms had an increased deltaPEFmin-min. In addition, workers with asthmatic symptoms were also more likely to have a higher PEF variability than workers without asthmatic symptoms. However, no difference in PEF variability between days with and without animals contact was observed. This study shows that the peak expiratory flow of workers who reported asthmatic symptoms due to working with rats decreased significantly on days working with laboratory animals.

Home recording of PEF in young asthmatics: does it contribute to management?

The value of home monitoring of peak expiratory flow (PEF) as part of an action plan for asthma management in children and young adults is uncertain. We sought to determine whether home recording of PEF benefited asthma management and whether any contribution was affected by the severity of the asthma. Twenty-eight children and young adults with asthma of different severity (mean age 14 yrs; 95% confidence interval (95% CI) 12-16 yrs) recorded their symptoms, drug consumption and PEF twice daily for a mean of 82 days over a 12 week period, and attended the laboratory every 2 weeks for measurement of lung function. The number of individual patients with significant correlations for laboratory lung function tests compared with ambulatory PEF and diary scores averaged over the preceeding 2 weeks was low in all severity groups. When measured in the laboratory, PEF meter readings correlated poorly with PEF measured by spirometry. The proportion of patients with significant correlations for PEF, symptoms and rescue bronchodilator use on a day-to-day basis was 70-80% in the group of severe asthmatics and significantly less in the mild asthmatics. In a subgroup of 14 patients who were sick on a mean of 19 days, the mean difference in PEF between well and sick days was 14% of predicted. Diurnal PEF variation correlated poorly with other parameters in all groups. It is concluded that PEF monitoring adds little to daily recording of symptoms and bronchodilator use in the management of young patients with severe asthma, and it is too insensitive to register meaningful clinical changes in those with milder asthma.

Magnesium Sulfate in Exacerbations of Chronic Obstructive Pulmonary Disease

Acute exacerbations of chronic obstructive pulmonary disease are commonly seen and difficult to treat. We sought to determine the bronchodilator efficacy of magnesium sulfate in this situation, as this compound is helpful in acute asthma. Subjects who came to either of two Veterans Affairs emergency departments were randomized in a double-blind fashion to receive either 1.2 g of magnesium sulfate or placebo over 20 minutes after they first received albuterol, 2.5 mg by nebulization. Peak expiratory flow, dyspnea scores, arterial hemoglobin oxygen saturation by pulse oximetry, maximal inspiratory and expiratory pressures, and vital signs were monitored for 45 minutes after the start of magnesium sulfate or placebo treatment. Seventy-two individuals were studied. The peak expiratory flow increased 16.6% +/- 27.7% (mean +/- SD) in both groups after the initial albuterol treatment, from 121.2 +/- 55.7 L/min to 136.9 +/- 63.9 L/min. The peak expiratory flow increased from 136.7 +/- 69.7 L/min at the start of the infusion to 162.3 +/- 76.6 L/min at 30 minutes and 161.3 +/- 78.7 L/min at 45 minutes with magnesium sulfate treatment. The peak expiratory flow was 137.0 +/- 58.6 L/min on initiation of the intravenous infusion, 143.0 +/- 72.7 L/min at 30 minutes, and 143.3 +/- 70.5 L/min at 45 minutes in the placebo group. The difference in peak expiratory flow from initiation of the infusion to 30 and 45 minutes later (calculated as means of the 30- and 45-minute values) was significantly different for the two groups (25.1 +/- 35.7 L/min vs 7.4 +/- 33.3 L/min; P = 0.3); the difference was also significant when expressed as percentage increase (22.4% +/- 28.5% vs 6.1% +/- 24.4%; P = .01). There was a statistically nonsignificantly trend toward a reduced need for hospitalization in the magnesium sulfate group as compared with the placebo group (28.1% vs 41.9%; P = .25). There were no significant changes in the other parameters with either treatment. Magnesium sulfate, 1.2 g over 20 minutes after beta-agonist administration, is safe and modestly efficacious in the treatment of acute exacerbations of chronic obstructive pulmonary disease, and its bronchodilator effect is greater than that of a beta-agonist given alone and lasts beyond the period of magnesium sulfate administration.