Peak Expiratory Flow Recordings Research Articles

Corticosteroid trials in non-asthmatic chronic airflow obstruction: a comparison of oral prednisolone and inhaled beclomethasone dipropionate.

One hundred and twenty seven adults considered on clinical grounds to have non-asthmatic chronic airflow obstruction entered a randomised, double blind, placebo controlled, crossover trial comparing the physiological response to inhaled beclomethasone dipropionate 500 micrograms thrice daily with oral prednisolone 40 mg a day, both given for two weeks. One hundred and seven patients completed the study. Response was assessed as change in FEV1 and FVC measured on the last treatment day, and as change in mean peak expiratory flow (PEF) over the final seven days of treatment from home PEF recordings performed five times daily. A full response to treatment was defined as an increase in FEV or FVC, or an increase in mean daily PEF over the final seven days of treatment, of at least 20% from baseline values. An improvement in one measurement of at least 15%, or of 10% in any two measurements, was defined as a partial treatment response. Response to placebo showed a significant order effect, suggesting a carry over effect of active treatment of at least three weeks. Response to active treatment was therefore related to initial baseline values, and compared with placebo by considering responses in the first treatment phase only. A full response to oral prednisolone (16/38) was significantly more common than to placebo (3/35). The number of full responses to inhaled beclomethasone (8/34) did not differ significantly from the number responding to oral prednisolone or placebo in the first treatment phase, though full and partial responses to inhaled beclomethasone (12/34) were significantly more common than those to placebo (4/35). When all three treatment phases were considered 44/107 patients showed a full response to one or both forms of corticosteroid treatment, a response to prednisolone (39) occurring more frequently than to inhaled beclomethasone (26). Only 21 of the 44 responders showed a response to both forms of treatment. Inhaled beclomethasone dipropionate 500 micrograms thrice daily was inferior to oral prednisolone 40 mg per day, but better than placebo, in producing improvement in physiological measurements in patients thought to have nonasthmatic chronic airflow obstruction. It was, however, an effective alternative in over half of those showing a response to prednisolone.

The distribution of peak expiratory flow variability in a population sample.

Although serial peak expiratory flow (PEF) measurements are often used to assess the variability of airflow obstruction, the range of values to be expected in the general population has never been defined, nor is there any consensus as to how PEF variability should be expressed. We have compared PEF recordings made by 121 subjects selected at random from the population of a small town (Group A) and 221 subjects selected because of wheeze in the last year (Group B). Subjects were asked to record PEF every 2 h during waking hours for 7 days using a mini-Wright peak flow meter. Seven indices of PEF variability were derived for each subject and the range for each index determined. All indices showed a positively skewed distribution in the random sample. Two variability indices, standard deviation percent mean and amplitude percent mean, provided the greatest separation between subjects with both a diagnosis of asthma and wheeze in the last year and subjects with neither feature and also provided the highest intra-class correlation coefficients. We conclude that amplitude percent mean and standard deviation percent mean provide the best means of expressing PEF variability for epidemiological purposes, but that amplitude percent mean is more easily derived and appears to be the index of choice. PEF variability has a continuous distribution in the general population and no clear-cut division between asthmatic and nonasthmatic subjects can be defined.

Home recording of peak expiratory flow rates and perception of asthma.

Fourteen asthmatic children, aged 7.9 to 18.0 years (mean, 11.3 years), recorded peak expiratory flow rates three times a day at home for four weeks in an attempt to improve perception of their airway obstruction. Pulmonary function tests were performed and a subjective severity score was recorded before and after this period. The accuracy of the parents' perceptions of their child's airway obstruction was also assessed. These children were unable to accurately predict their degree of airway obstruction, and no improvement in prediction was seen following the learning period. Parents' perceptions of the child's airway obstruction were also inaccurate. Recording of peak expiratory flow rate at home did not improve the child's perception of his asthma. Rational management of troublesome asthma requires the use of an inexpensive peak flowmeter to provide continual objective measurements of lung function.

DIDYMELLA EXITIALIS AND LATE SUMMER ASTHMA

4 patients in whom Didymella exitialisseemed to be an important cause of their asthma were investigated. All 4 patients had immediate skin-prick test reactions and specific IgE antibody to D exitialisand Alternaria alternata. Inhalation of a soluble extract of D exitialis provoked immediate asthmatic reactions in these 4, but not in a skin-prick-test-negative volunteer. Radioallergosorbent inhibition studies with D exitialis and A alternatashowed self and cross inhibition, which suggested shared antigens. During summer, 1983, 1 of the 4 recorded peak expiratory flow rate (PEFR) twice a day. Spore counts of D exitialis and A alternata were made during this time. Falls in PEFR occurred when D exitialis spore counts increased, usually after a rainfall. Of 34 allergy clinic patients, 6 had skin-prick test reaction to both fungi, but 2 had reactions to A alternata only and 3 to D exitialis only, which suggests the existence of specific antigens. D exitialis seems to be a cause of late summer asthma. Its importance is not known, but allergy to it may contribute to asthma following thunderstorms.

Comparison of four weeks' treatment with fenoterol and terbutaline aerosols in adult asthmatics: A double-blind crossover study

Fenoterol and terbutaline, two long-acting β 2-adrenoceptor agonists in aerosol form, were compared in an 8-wk randomized double-blind crossover study in 22 mild to moderately severe asthmatics. Patients completed diary cards, recorded peak expiratory flow rate (PEFR) twice daily, and attended a clinic for measurement of PEFR, 1-sec forced expiratory volume (FEV 1 ), and forced vital capacity (FVC) twice during each treatment period. Fifteen patients completed the study; 5 dropped out while using fenoterol, and 2 while using terbutaline. At clinic attendances, the patients had a significantly higher mean PEFR after 4 wk on terbutaline (385 L/min) than after fenoterol (316 L/min) (p < 0.001). Similar results were found on analysis of the morning and evening PEFR recordings. On comparing each individual's PEFR recordings during the 2 treatments, it was found that there was no significant difference among the treatments in 3 patients, while 9 patients had a better response to terbutaline, and 3 patients had a better response to fenoterol. While similar numbers expressed a subjective preference for each treatment, the lung function data suggested that the effectiveness of fenoterol appeared to decline during the trial period.