Long-term Follow-up of Pulmonary Function in Bronchial Asthma Patients Treated with Pranlukast

Clinical studies have shown that pranlukast, a selective cysteinyl leukotriene antagonist, is effective for bronchial asthma. In the present paper, we retrospectively analyzed long-term asthma control by pranlukast treatment in patients treated with inhaled corticosteroids. We analyzed medical records and asthma diaries of 21 patients (9 males, 12 females) (52.1 ± 3.5 years of age) with bronchial asthma who experienced increase of more than 10 L/min in peak expiratory flow in the first 4 weeks of treatment with pranlukast (450 mg/day) and were subsequently treated with pranlukast for more than 1 year. They all received inhaled corticosteroids (400–1600 µg/day of beclomethasone dipropionate or equivalent). We examined clinical control in terms of time course of self-monitored peak expiratory flow. During the analyzed period, the dose of inhaled corticosteroids was tapered in 4 patients, constant in 15 patients and increased in 2 patients. In 19 patients treated with unchanged or tapered dose of inhaled corticosteroids, improvement in the increase of mean PEF at 4-week treatment was maintained for 1 year. No difference in the add-on effect of pranlukast was observed in patients treated with less than 800 µg and more than or equal to 800 µg of inhaled corticosteroids. Four patients underwent reduction of inhaled corticosteroids in the analyzed period and PEF was well-maintained and even increased by pranlukast treatment. In 11 patients in whom data for 3 years were available, the improvement in PEF persisted for 3 years. Although the present investigation is a retrospective analysis, these data may suggest that pranlukast has no tachyphylaxis and its effect continues for more than 1 year.     

Monitoring of Peak Expiratory Flow Rates in Cork Workers' Occupational Asthma

Suberosis is an occupational lung disorder of cork industry workers usually presenting as an extrinsic allergic alveolitis, but airway involvement in some cases makes the diagnostic approach complex. We assessed peak expiratory flow rates (PEF) in 17 cork workers with asthma symptoms that worsened at work, comparing three methods of PEF graph analysis. Complete agreement (three observers) was found in 12 of 17 cases (70.6%) with the visual inspection of mean daily values and in 11 of 17 cases (64.7%) with the minimum, maximum, and mean daily values (without any consensus in two cases). According to the mean PEF graph, there were eight positive readings (47%), five negative readings (29%), and four dubious readings (24%); with the other graphic analysis, two of the dubious cases were reclassified as negative. When we analyzed daily variability ≥20%, we found only three positive results, one of which was in absolute disagreement with the visual analysis. Our results suggest that it is possible to demonstrate occupational asthma in cork work exposure. The visual inspection of PEF monitoring shows a greater number of positive results than the index of daily variability; however, the latter may help to sort out dubious cases.     

Monitoring of Peak Expiratory Flow Rates in Cork Workers' Occupational Asthma

Suberosis is an occupational lung disorder of cork industry workers usually presenting as an extrinsic allergic alveolitis, but airway involvement in some cases makes the diagnostic approach complex. We assessed peak expiratory flow rates (PEF) in 17 cork workers with asthma symptoms that worsened at work, comparing three methods of PEF graph analysis. Complete agreement (three observers) was found in 12 of 17 cases (70.6%) with the visual inspection of mean daily values and in 11 of 17 cases (64.7%) with the minimum, maximum, and mean daily values (without any consensus in two cases). According to the mean PEF graph, there were eight positive readings (47%), five negative readings (29%), and four dubious readings (24%); with the other graphic analysis, two of the dubious cases were reclassified as negative. When we analyzed daily variability ≥20%, we found only three positive results, one of which was in absolute disagreement with the visual analysis. Our results suggest that it is possible to demonstrate occupational asthma in cork work exposure. The visual inspection of PEF monitoring shows a greater number of positive results than the index of daily variability; however, the latter may help to sort out dubious cases.     

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.     

A Preliminary Study of PEFR Monitoring in Patients with Chronic Cough

It is important to make a differential diagnosis of cough variant asthma in patients with chronic cough. To examine whether or not peak expiratory flow rate (PEFR) is useful for the differential diagnosis of cough variant asthma in such patients, diurnal variation rates of PEFR were calculated in 23 patients who presented with dry cough lasting four or more weeks and who showed no abnormalities on chest radiographs. None of the patients had wheezes, and pulmonary function testing at the time of visit to the hospital revealed no abnormalities. During the control period, the mean diurnal variation rate of PEFR in 23 patients was 16.3 ± 7.9%. Six, nine and eight patients had PEFR diurnal variations rates of <10% (Group 1), 10–19% (Group 2), and 20% (Group 3), respectively. At week 3 of treatment with bronchodilators, only Group 3 showed a significant decrease in PEFR diurnal variation rate from 25.7% to 10.1%. The cough score decreased significantly in Group 3 only. These patients had enhanced bronchial hyperresponsiveness and showed eosinophils in induced sputum, leading to the diagnosis of cough variant asthma (CVA). After making the diagnosis of CVA, an inhaled corticosteroid or a Th2 cytokine production inhibitor suplatast tosilate was administered to patients; consequently, they showed no recurrence of cough. PEFR monitoring allowed the detection of morning dip and was suggested to be potentially useful for the differential diagnosis of cough variant asthma in patients with chronic cough.     

Peak Expiratory Flow-Guided Self-Management Treatment of Asthma in Serbia

The aims of this study were to compare the efficacy of 1-year peak expiratory flow (PEF)-based self-management of asthma against conventional treatment and to analyze the long-term effectiveness of self-management. Eighty adult patients with persistent asthma (group B). After 1 year, significant improvement was noted in markers of asthma severity in group A but there were no changes in group B. After 6 years of the self-management program, asthma morbidity and emergency use of health services were reduced. These results show short-term and long-term effectiveness of a PEF-based self-management program in persistent asthma.     

Assessment of Diurnal Variability of Peak Expiratory Flow in Stable Asthmatics

Five daily readings of peak expiratory flow (PEF) were obtained for three days on 100 patients with chronic stable asthma. The variability of PEF was calculated as the amplitude percent mean (A%M) from the readings obtained on the third day, and compared to previously reported data from 152 healthy Indian adults. Patients with severe asthma exhibited significantly higher A%M than patients with both mild and moderate asthma (p<0.05), but there was considerable overlap across disease categories. The area under the receiver operating characteristic curve plotted to assess the performance of PEF variability as a discriminator in diagnosing asthma was 0.826, with best discrimination at a value of 12.5 (sensitivity 0.640, specificity 0.941). Using a cut-off value of 16.5 (as proposed earlier by us) improved specificity to 0.987 but reduced sensitivity to 0.510. Using a traditional cut-off of 20, specificity remained almost unchanged (0.993), but sensitivity dropped further to 0.440. Thus A%M>16.5 is a useful marker of bronchial asthma in epidemiological studies in India. However, its use in population screening, clinical diagnosis, or in the assessment of the severity of asthma in individual patients has serious limitations because of poor sensitivity.     

Is peak expiratory flow rate a predictor of complications in diabetes? The Wisconsin Epidemiologic Study of Diabetic Retinopathy

The Objective of this study was to determine whether peak expiratory flow rate is a predictor of complications of diabetes. Peak expiratory flow rate was measured at the 10-year follow-up (third examination) of a cohort of persons with younger-onset diabetes. The relationships of progression of diabetic retinopathy by two steps, progression to proliferative retinopathy and of incidences of macular edema, sore or ulcers on feet or ankles, lower extremity amputation, proteinuria, and cardiovascular disease 4 years after this examination with respect to peak expiratory flow rate were evaluated. Study procedures including measurements of blood pressure, height and weight, grading of fundus photographs, peak expiratory flow rate, urinalysis, and medical history were performed according to standard protocols. Peak expiratory flow rate was not associated in univariate analyses with progression of retinopathy, incidences of proliferative retinopathy, macular edema or lower extremity amputation, sores or ulcers on feet or ankles, gross proteinuria, or self-reported cardiovascular disease. However, when using multivariable models to include the effects of other risk factors, peak expiratory flow rate was significantly associated with the combined incidences of sores or ulcers on feet and ankles, or lower extremity amputations (OR=0.61, 95% CI 0.42–0.88). These data suggest that peak expiratory flow rate is a predictor of subsequent complications in the lower extremities in those with long duration of younger-onset diabetes. Evaluating this association in an incipient cohort would illuminate whether the relationship we found is likely to be causal.     

Asthma Health Status: Influence of Disease Severity Categorized by Peak Expiratory Flow

To evaluate the health status of patients with stable asthma and determine how disease severity affects the status, 68 consecutive patients were recruited from an outpatient clinic at an university hospital. Health status was assessed with the St. George's Respiratory Questionnaire and the Asthma Quality of Life Questionnaire (AQLQ). The results of the questionnaires revealed that the mean % predicted peak expiratory flow (PEF) in the preceding 2 weeks correlated most significantly with each total score for the two health status measures. We also found that, in the groups classified by mean % predicted PEF (mild, PEF ≧ 80%; moderate, 60 to 79%; severe, <60%), there were significant differences in all SGRQ scores (p < 0.05). In a subgroup analysis, the scores for moderate and severe patients were significantly worse than for mild patients in all four components (p < 0.05). Almost the same tendency was observed in the score distribution on the AQLQ. We conclude that mean % predicted PEF correlated most with the health status of the patients. Patients with PEF higher than 80% of predicted value generally maintained a better health status than did those with less than 80% of predicted PEF. Achieving higher than 80% of predicted PEF is important in managing asthma from the viewpoint of health status.     

Peak expiratory flow meters (PEFMs) – who uses them and how and does education affect the pattern of utilisation?

Background: Asthma control may be assisted by educating patients to use peak expiratory flow meters (PEFMs). Aims: To find out the sociodemographic and clinical characteristics of asthmatics attending an Emergency Room (ER) who owned PEFMs. Methods: We undertook a study of 352 asthmatics aged seven to 55 years who attended an ER. The following were analysed: their pattern of peak flow monitoring (PFM), the factors associated with ‘appropriate’ or daily PFM on entry to the study and then prospectively; whether asthma education influenced utilisation and whether there was a reduction in ER use or admissions in those who acquired a PEFM. Results: Those owning a PEFM at entry to the study (54%) had more asthma morbidity (p= 0.0001), had had asthma for longer (p = 0.0001), had seen their medical practitioners more often in the previous nine months (p = 0.0001), were on more asthma medications (p= 0.0001) and were more likely to have been to an Asthma Clinic (p = 0.0001). Those not owning a PEFM were more likely to be of lower social class (p = 0.016) and of Pacific Island origin (p= 0.0001) suggesting that distribution is not ideal and is influenced by disease severity, amount of health care use and sociodemographics. Patients with a self-management plan (35% of PEFM owners) and those receiving ‘good care’ or management, were more likely to use PFM ‘appropriately’ and to mention PFM in a scenario evaluating their response to worsening asthma control and argues for PEFMs to be distributed only in conjunction with a self-management plan, and therefore in close association with the patients' medical practitioners. Most patients (75%) appeared to prefer making management decisions based on symptoms rather than on their peak expiratory flow (PEF) and few (16%) performed daily PFM at entry to the study and fewer (6%) nine months later. There was an improvement in the pattern of PFM after education, but the acquisition of a PEFM made no difference to the frequency of ER use or admission, Conclusion: More realistic goals need to be defined in relationship to PFM which may improve patients' acceptance of the strategy, and therefore, hopefully their compliance. Such strategies need to be consistently reinforced over time for them to have an impact on asthma morbidity. (Aust NZ J Med 1994; 24: 521–529.)     

Peak Expiratory Flow Associated with Change in Positioning of the Instrument: Comparison of Five Peak Flow Meters

To determine if peak expiratory flow (PEF) is altered by incorrect positioning of five peak flow meters (PFMs), 16 adults with clinically stable persistent asthma were evaluated. After inhaling two puffs of albuterol via AeroChamber, patients were instructed over the next 15 min in correct PFM technique and two incorrect techniques (PFM angled 20° left in mouth and PFM pointed 20° downward as patient leaned forward with maximal exhalation). Order of use of five peak flow meters and correct vs. incorrect techniques were random. Although mean values generally indicated no clinically meaningful effect of positioning of the PFM, inaccurate PEFs were recorded for several subjects with both incorrect methods and all PFMs.     

气急鉴别指数判别呼吸困难类型的初步研究

目的 探讨气急鉴别指数（dyspnea differentiation index,DDI）判别肺源性呼吸困难与心源性呼吸困难的优越性。方法 测定116例急性呼吸困难的PaO2和PEF值，根据Rajesh K.Ailani等立的公式计算气急鉴别指数DDI，用DDI对116例急性呼吸困难的原因进行判别并与PEF和临床表现的诊断符合率相比较。结果 DDI、PEF和临床表现对116例生呼吸困难的原因的诊断符合率分别为92.7%、77.5%、68.9%。结论 用DDI判别肺源性呼吸困难与心源性呼吸困难具有较高的诊断符合率，明显优于PEF和临床表现。     

Airway Inflammation in Premenstrual Asthma

Premenstrual asthma (PMA) is a clinical picture with worsening of asthmatic symptoms and pulmonary functions in the late luteal phase of the menstrual cycle. The aim of this study was to evaluate the inflammatory changes in asthmatic women who complain of PMA.

Forty asthmatic women attending our outpatient clinic were questioned about worsening of their asthma before menstruation. Eleven women (aged 17–40) who complained of PMA participated in the study. Subjects were asked to record peak expiratory flow rates, symptom scores, and β-agonist use daily. After the first menses on the seventh day of their cycle, and before the onset of the next menstruation, on the 26±3rd day of the cycle, patients were evaluated with pulmonary function tests, methacholine challenge test, and fractionated exhaled nitric oxide (Fe_NO) levels. Eosinophils in peripheral blood and induced sputum were also evaluated.

When comparing the two groups of results, the significant changes were in Fe_NO levels, day-time symptom scores, and eosinophils in induced sputum (29.25 ppb/9.16 ppb p<0.05, 1/0.45 p = 0.05, %6.63/%4.09 p<0.01, respectively, before and after menstruation).

These results show that PMA is not only a clinical picture with a decrease in airway calibre that can be related to the regulation of 2 receptors, but also a complex state with worsening of airway inflammation.     

Effect of Pranlukast, a Leukotriene Receptor Antagonist, in Patients with Severe Asthma Refractory to Corticosteroids

We investigated the effect of pranlukast (ONO-1078), a cysteinyl leukotriene receptor antagonist, in 11 patients with severe bronchial asthma. The patients had been treated with 1600 μg/day of beclomethasone or 800-1600 ug/day of beclomethasone plus 2.5-20 mg/day of prednisolone, but remained symptomatic. After a 2-week baseline period, the patients received 225 mg of pranlukast twice daily for 8 weeks. Morning and evening peak expiratory flow rate (PEF) and symptom scores (cough, dyspnea, sleep) were recorded in an asthma diary. Ten patients completed the study. Symptom scores, especially dyspnea and sleep scores, and the number of rescue β₂-agonist inhalations were significantly decreased. The morning PEF significantly improved from a mean baseline value of 311 to 341 L/min by the end of the study period. The evening PEF also improved, from 328 to 348 L/min, although the difference was not significant. These results suggest that pranlukast may be effective in treating patients with severe asthma who are refractory to corticosteroid therapy.     

Laboratory and Clinical Evaluation of a Portable Computerized Peak Flow Meter

A mini-Wright based peak flow meter (VMX Mini-Log), which stores the readings together with the time and date of each measurement, has recently been marketed but has not yet been evaluated. The accuracy, reproducibility, and interdevice variability of this instrument were investigated using a pneumotachograph connected in series as a standard. Flows from 100 to 700 L/min were generated by an explosive decompression chamber. The performance of this instrument was also tested in 20 normal subjects and in 20 patients with airflow obstruction. The accuracy of the instrument was expressed as the percentage of error, and reproducibility and interdevice variability were assessed using the coefficient of variation. In the laboratory evaluation, all devices recorded flow rates that were within 10% of the pneumotachograph readings at flows between 200 and 600 L/min. At the extreme flow rates of 100 and 700 L/min, the mean error was higher than 10%. The reproducibility of the VMX was within 5% at all the flows tested. The interdevice variability was less than 5% at flow rates between 200 and 700 L/min. When tested on normal subjects with PEF between 400 and 700 L/min, the VMX performed well. In patients with airflow obstruction, four devices had greater than 10% error. The largest error was observed in those patients with PEF below 200 L/min. The VMX Mini-Log peak flow meter is accurate and precise in the flow range between 200 and 600 L/min. Its performance, however, may be affected in subjects with airflow obstruction and PEF below 200 L/min.     

支气管哮喘的气道重构与药物治疗

气道重构是支气管哮喘（哮喘）的特征性病理改变,成为顽固性哮喘的病理基础,直接影响哮喘的治疗效果。因此,研究气道重构的发生机制,探究防治气道重构的方法具有重要意义。     

Symptom perception and functional morbidity across a 1-year follow-up in pediatric asthma

The purpose of this study was to examine the association between asthma symptom perception measured during a 5-6 week baseline and functional morbidity measured prospectively across a 1-year follow-up. Symptom perception was measured by comparing subjective ratings with peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV(1)). We hypothesized that accurate symptom perception (ASP) would be associated with less functional morbidity. Participants consisted of 198 children with asthma ages 7-17 recruited from three sites. The children used a programmable electronic spirometer in the home setting to guess their PEFR prior to exhalation. Each "subjective" guess was classified as being in an ASP, dangerous symptom perception (DSP; underestimation of symptoms), or symptom magnification (SM; overestimation) zone based upon the corresponding measurement of PEFR or FEV(1). An index of functional morbidity was collected by parent report at baseline and across 1-year follow-up. A greater proportion of ASP blows and a lower proportion of DSP blows based on PEFR predicted less functional morbidity reported at baseline, independent of asthma severity and race/ethnicity. A greater proportion of ASP blows (using PEFR and FEV(1)) and a lower proportion of SM blows (using FEV(1)) predicted less functional morbidity across 1-year follow-up. Symptom perception was not associated with emergency department visits for asthma at baseline or across follow-up. In comparison to PEFR, FEV(1) more frequently detected a decline in pulmonary function that children did not report. Symptom perception measured in naturalistic settings was associated with functional morbidity at baseline and prospectively across 1-year follow-up. Support was found for including multiple measures of pulmonary function in the assessment of asthma symptom perception.     

Relationship Between Peak Expiratory Flow Rate and Shoulders Posture in Healthy Individuals and Moderate to Severe Asthmatic Patients

Introduction. Asthma overloads respiratory muscles causing changes in posture. Objectives. To evaluate shoulder position in asthmatics and its correlation to the peak expiratory flow rate (PEFR). Methods. A cross-sectional study involving 19 asthmatics (study group) and 20 healthy volunteers (control group). Assessment of PEFR was used to determine airway obstruction. Shoulder position was quantified as the ratio between the front and back measurements, in centimeters, of the distance between the two outermost points of each scapula. Shoulder position measurement (SPM) ratio data from both groups were compared and correlated to PEFR. Results. The asthmatics presented lower PEFR (279 ± 64 L/min) and SPM (0.88: range 0.83–0.9) than did control subjects (555 ± 100 L/min and 0.97: range 0.95–1, respectively) (p < 0.001). There was a correlation between PEFR and SPM (asthmatics r = 0.8; controls r = 0.5). Conclusion. Determining SPM ratios allowed us to identify those postural alterations that correlated with pulmonary function in asthmatics and in healthy individuals. Further investigation is needed before SPM can be used as a tool for clinical evaluation of asthma patients.     

Diurnal Variability of Lung Function and Its Association with Sleep among Patients with Asthma

This prospective exploratory story examined diurnal variations in pulmonary function and their association with sleep and quality of life (QOL) in 20 adult asthmatics. Peak expiratory flow (PEF) was assessed for 7 days, before bedtime and upon awakening. There was no association between PEF variability and QOL. Six of 13 polysomnographic measures were significantly correlated with overnight decline in PEF. Individuals with greatest decline took longer to fall asleep and enter Stage 1 sleep, spent less time asleep, and experienced poorer sleep efficiency. Diurnal variations in PEF reflect adverse sleep quality, yet impact on QOL is often unnoticed.     

呼气相气道内负压法检测呼气流速受限应用于儿童支气管激发试验的可行性

目的 观察支气管哮喘(简称哮喘)患儿支气管组胺激发试验前、后呼气流速受限(EFL)情况,并与常规的以第1秒用力呼气容积(FEV1)作为判断指标的支气管激发试验结果进行比较,探讨EFL作为支气管激发试验判断指标的可行性.方法 非急性发作期哮喘30例患儿,采用呼气相气道内负压(NEP)法检测患儿支气管组胺激发试验前、后EFL情况.结果 30例非急性发作期哮喘息儿中,支气管组胺激发试验阳性者(BPT阳性组)19例,阴性者(BPT阴性组)11例.BPT阳性患儿激发前、后FEV1分别为(1.71±0.52)L和(1.21±0.34)L,FEV1下降率为(29.04±7.49)%,19例BPT阳性患儿激发前和激发后分别有1例和3例出现卧位EFL,坐位时均无EFL,患儿3分法EFL和5分法EFL激发前(分别为1.05±0.23和0.05±0.22)与激发后(分别为1.16±0.37和0.26±0.65)比较差异均无统计学意义(t分别为1.455和1.714,P分别为0.163和0.104).BPT阴性患儿激发前、后FEV1分别为(1.89±0.80)L和(1.79±0.78)L,FEV1下降率为(6.09±5.29)%,11例BPT阴性患儿激发前与激发后均无EFL.结论 NEP法检测EFL不能敏感反映传统支气管激发试验阳性判断标准(FEV1下降≥20%)的变化,其在支气管激发试验中的可行性和阳性判断标准尚有待进一步研究探讨.