Assessment of the child with asthma

Development of online diary and self-management system on e-Healthcare for asthmatic children in Taiwan

OBJECTIVE

Many regional programs of the countries educate asthmatic children and their families to manage healthcare data. This study aims to establish a Web-based self-management system, eAsthmaCare, to promote the electronic healthcare (e-Healthcare) services for the asthmatic children in Taiwan. The platform can perform real time online functionality based upon a five-tier infrastructure with mutually supportive components to acquire asthma diaries, quality of life assessments and health educations.

METHODS

We have designed five multi-disciplinary portions on the interactive interface functioned with the analytical diagrams: (1) online asthma diary, (2) remote asthma assessment, (3) instantaneous asthma alert, (4) diagrammatical clinic support, and (5) asthma health education. The Internet-based asthma diary and assessment program was developed for patients to process self-management healthcare at home. In addition, the online analytical charts can help healthcare professionals to evaluate multi-domain health information of patients immediately.

RESULTS

eAsthmaCare was developed by Java™ Servlet/JSP technology upon Apache Tomcat™ web server and Oracle™ database. Forty-one voluntary asthmatic children (and their parents) were intervened to examine the proposed system. Seven domains of satisfiability assessment by using the system were applied for approving the development. The average scores were scaled in the acceptable range for each domain to ensure feasibility of the proposed system.

CONCLUSION

The study revealed the details of system infrastructure and developed functions that can help asthmatic children in self-management for healthcare to enhance communications between patients and hospital professionals.

Development of pediatric pulmonology in the United Kingdom, Europe, and Australasia

The organization of medicine in Europe, the UK and the Commonwealth countries was always much less formal than in the USA for many years and pediatricians interested in pediatric lung disease and asthma often started off as adult internists or specialists in adult pulmonary medicine. The early leaders in developing a special interest in the breathing of children during the 1940s and 1950s were predominantly physiologists and clinicians who began to apply physiological techniques to the study lung function in healthy and sick infants and children. A major contribution to our understanding of the epidemiology of wheezing in children was the early establishment of a cohort study in Australia which is still yielding important information. It was during the early 1970s that pediatric pulmonary "politics" began to emerge in the UK when pediatricians interested in lung diseases began to arrange an informal society and meet regularly under the auspices of the British Paediatric Association. In fairly characteristic fashion, pulmonology in Europe was represented for a while by several different societies but due to the efforts of some dedicated enthusiasts there finally emerged the Paediatric Assembly of the European Respiratory Society (ERS) and its first Head, Max Zach, went to become President of the ERS itself. Despite some early doubts abut the future for pediatric pulmonology as a specialty in Europe and Australasia it is clearly flourishing as shown by the rising membership of the professional societies and the constant stream of high quality basic science and clinical publications.

Validation of a pediatric asthma caregiver diary

BACKGROUND

Young children are generally not able to consistently and reliably perform tests of airway function, and normative values are not available. Reliable and valid measures of parental reporting of asthma symptoms and functioning are needed to determine the efficacy of asthma interventions.

OBJECTIVE

A pediatric asthma caregiver diary was developed and validated for use in interventional asthma studies.

METHODS

A 3-week prospective study of 125 caregiver parents and their children, aged 2 to 5 years, with persistent asthma was conducted. At baseline, children were classified as either stable (no change to anti-inflammatory therapy) or unstable (anti-inflammatory therapy added or increased).

RESULTS

A symptom scale and day without asthma symptoms (DWAS) were defined from pediatric asthma caregiver diary questions. The scale and DWAS statistically differentiated between the stable and unstable groups at week 1 and detected change between the 2 groups (P <.01). On average, caregivers reported low symptom scores. However, the frequency of DWAS was only 43% of days in the stable group and 22% in the unstable group.

CONCLUSION

The pediatric asthma caregiver diary scale and DWAS have acceptable measurement characteristics for use in clinical trials of children with asthma symptoms. The DWAS indicates an opportunity for improvement in asthma control in this population.

Validation of an asthma symptom diary for interventional studies

OBJECTIVE

The Pediatric Asthma Diary was developed and validated to assess efficacy of interventions in children with asthma.

DESIGN, PATIENTS, AND SETTING

Diary validation was performed in a three week, prospective study of 106 children aged 6-14 years with asthma. Children were classified at baseline as either stable (requiring no additional asthma treatment) or new onset/worse (requiring either addition of or increase in anti-inflammatory treatment).

RESULTS

A daytime symptom scale and "day without asthma" were defined from diary questions. Both measures demonstrated significant validity and responsiveness to anti-inflammatory treatment. The stable group experienced a higher percentage of days without asthma during week 1 compared with the new onset/worse group (39.6% v 11.6%, respectively). The new onset/worse patients experienced significant improvement in days without asthma (24.5%) compared with stable patients (6.4%).

CONCLUSIONS

The Pediatric Asthma Diary daytime symptom scale and day without asthma are acceptable measures for use in asthma intervention studies of children aged 6-14 years.

Dose titration of nebulized budesonide in young children

We compared the clinical effect of the glucocorticoid budesonide delivered from two nebulizers Aiolos and Pari LL in 38 children less than 4 years of age (mean age, 20.2 months) with chronic wheeze. The design was a controlled, single-blind, randomized, cross-over, dose titration study. After a 1-week run-in, patients were randomized to treatment with 1 mg budesonide b.i.d. for 2 weeks from either an Aiolos or a Pari LL nebulizer. This was followed by a gradual dose reduction period during which the budesonide dose was reduced at 2-week intervals until unacceptable asthma symptoms appeared or the placebo level was reached. The patient was then switched to budesonide 1 mg b.i.d. from the other nebulizer for 2 weeks, after which the dose was reduced at 2-week intervals as described for the first period. Patients who completed the study on placebo for 2 weeks without deterioration of their asthma were not included in the statistical analysis. During Period #1 the minimum effective dose of budesonide was 2 mg/day in 9 patients, 1 mg/day in 10 patients, and 0.5 mg/day in 13 patients. In Period #2 the corresponding figures were 14, 5, and 13 patients. Six patients were excluded after the first period because their asthma control did not deteriorate during dose reduction and when finishing on placebo for 2 weeks. For both nebulizers the reduction in budesonide dose was associated with a small increase in symptoms and use of rescue terbutaline. The mean dose of budesonide delivered to the patient by the Aiolos was twice as large as that delivered by the Pari LL: 26% vs. 13% of the nominal dose assessed by the filter method. Nevertheless, no statistically significant difference in clinical effect or mean minimal effective dose (1.1 mg for Aiolos and 1.2 mg for Pari LL) could be detected between the two nebulizers. No serious adverse events were observed. We conclude that the minimal effective dose of nebulized budesonide varies from 0.5 to 2.0 mg/day in young children with asthma. A higher drug delivery, as assessed by the filter method, does not necessarily result in better clinical control or lower minimal effective dose. Further studies are needed to assess whether this is due to insufficient sensitivity of the study design in detecting a difference in clinical effect, or whether measurements of drug delivery by the filter method do not reflect lung deposition or clinical effect in young children with wheezing.

Treatment of severe steroid dependent preschool asthma with nebulised budesonide suspension

The steroid sparing effect of nebulised budesonide suspension was assessed in a double blind placebo controlled parallel group study of 36 preschool children with severe asthma who were dependent on treatment with oral steroids. Nebulised budesonide suspension significantly reduced the requirement for treatment with oral steroids, and produced a marked improvement in overall health as scored on a visual analogue scale during the clinic visits. This study shows a significant step forward in the prophylactic treatment of asthma in children under the age of 3 years, in whom the efficacy of many other nebulised treatments has been questioned.

Community indicators of child health

Indicators of health in child populations are critically reviewed and the potential for routinely collected morbidity and life quality data discussed. A short list of currently available, routinely collected child health data is proposed which, if available for all European countries, would form the basis of a useable and comparable European child health data base. A European consensus group on child health indicators is proposed and further research into morbidity and life quality measures relevant to children recommended.

Peak flow in children aged 4-16 years. Normal values for Vitalograph peak flow monitor, Wright and Mini Wright peakflow meters

Peak expiratory flow rate was measured in 318 Swedish children aged 4-16 years on Wright peak flow meter, Mini Wright peak flow meter and Vitalograph peak flow monitor. We found that height, age and sex had a significant effect on the regression equation. Weight and body surface area did not add any significant information. The curves for the Wright and Mini Wright peakflow meters are presented and may be used as normal references in the clinic. Mini Wright peakflow meter and Vitalograph peak flow monitor are cheap and handy but results on different instruments should not be directly compared.

The potential value of a 750-ml spacer for the administration of inhaled corticosteroids to children

An open, cross-over trial was conducted on 25 asthmatic children, aged 6-13 years, who required inhaled steroids. They inhaled Budesonide 200 micrograms twice daily, either directly from the metered dose inhaler or via the pear spacer (PS), for 2 months on each, in randomized order. The effects of the treatment were monitored with diary cards recording peak expiratory flow rates twice daily, symptoms and treatment taken, and with monthly clinical assessments including more sensitive lung function studies (flow-volume loops and single breath nitrogen wash-out tests). There was no specifically PS-related improvement in symptoms or in the majority of tests, but the results showed improvement with time when using either method. The improvement was more distinct in some tests reflecting proximal airway calibre (i.e., PEFR) than in tests thought to reflect predominantly peripheral airway calibre (i.e., F50, RV). The bronchodilator responsiveness, as shown by the increase in lung function tests after a beta-agonist was given, was significantly greater for FVC during the periods when the PS was used, although there was no significant improvement in FEV2 or PEFR. The improvement in tests reflecting proximal airways may have been due to optimization of the inhalation technique, greater understanding of asthma, or better compliance with medication associated with regular attendance for the study. The greater bronchodilator response whilst children were inhaling budesonide by the PS may have been due to increased deposition or better distribution of the steroid but was probably related to a difference between the two groups in initial baseline function tests.

Night cough counts and diary card scores in asthma

A tape recording system for recording night cough in asthmatics at home is described. Objective cough counts and half hour periods containing cough did not correlate with diary card scores awarded to eight children on seven nights each. Night cough diary scores may mislead in the assessment of symptom severity.

Exercise conditioning in children with asthma

A controlled study of 20 children with asthma who participated in a 4-month running program (30 min/day, 3 days/wk), using inhalation of a beta-2 stimulant prior to each running session to prevent exercise-induced asthma, showed significant increases in work tolerance (120.5 +/- 45.0 W before, 131.5 +/- 43.5 W after, P = 0.002) and cardiopulmonary fitness (peak oxygen consumption 37.6 +/- 8.6 ml/kg/min before, 43.1 +/- 10.5 ml/kg/min after, P less than 0.001). Asthma severity judged by daily asthma diary scores and twice daily peak flows did not change. Thirteen control patients with asthma did not exercise and demonstrated no change in work tolerance, fitness, or severity of asthma. Thus, children with asthma can safely engage in a running program and can increase work tolerance and fitness without worsening their asthma.

Variability of peak flow in wheezy children

A study of peak flow variability was carried out among a population sample of 63 wheezy children aged 9-11 years. Recordings were made over 12 days at three times during the day--first thing in the morning, on returning home from school and at bedtime. Eighty nine per cent of the children had symptoms during the diary period. The mean amplitude (difference between the highest and lowest daily peak flow values) was 17% of the mean daily value (range 4-48%). By cosinor analysis the amplitude was 12% of the mean value (range 1-53%). In 65% of the children the lowest point of the daily rhythm as determined by cosinor analysis lay between midnight and 8am; the rhythm was, however, statistically significant in only fourteen individuals (22%). These levels of variability are considerably lower than those previously reported in hospital based studies of adult asthmatics. As a method of demonstrating variable airflow obstruction, which is the defining physiological characteristic of asthma, the use of a peak flow diary alone appears to be of limited value in children.

Inhaled Fenoterol powder in asthma: a long term study

A study was designed to assess the long term efficacy of Fenoterol powder in asthmatic children. The design included an initial assessment period and a further evaluation after six months, in which Fenoterol or placebo treatments were administered on consecutive days. Objective measurements were obtained from PEFR and FEV1. A diary record was kept to monitor compliance and side effects. A minimum dose of 200 mcg Fenoterol powder was prescribed three times per day. The bronchodilator action of Fenoterol was sustained after a period of six months, in the absence of significant side effects.

Relationship of exercise-induced asthma to clinical asthma in childhood

Thirty-three asthmatics were followed up for a mean of 8 1/2 years in prospective study in order to observe the clinical course of the disease. The severity of asthma was graded according to the treatment each required to keep him in reasonable health. Regular exercise tests were performed so that a comparison could be made between the degree of exercise-induced asthma and the severity of the disease. In this group of severe perennial childhood asthmatics profound exercise-induced asthma was found to exist throughout the entire clinical spectrum of the disease with no appreciable difference until the patient became symptom-free. Exercise-induced asthma then disappeared only to return if clinical asthma recurred. This study showed that exercise-induced asthma is a sensitive indicator of clinical asthma but has no prognostic significance in the symptom-free patient.

Ketotifen in childhood asthma: a double-blind placebo controlled trial

In a three week double-blind cross-over controlled trial in twenty asthmatic children, ketotifen (HC 20-511, 'Zaditen', Sandoz) showed no significant difference from placebo, although there was a consistent trend in favour of the active drug.

A clinical comparison of beclomethasone dipropionate delivered by pressurised aerosol and as a powder from a rotahaler

14 children with severe asthma were studied for 2 months in a double-blind cross-over trial to compare the efficacy of beclomethasone dipropionate delivered as an aerosol and as a powder from a rotahaler. Inhalation via the aerosol was satisfactory in 13 patients, each of whom used the rotahaler correctly. Younger children preferred to use the rotahaler. Comparison of daily symptoms, twice daily peak expiratory flow rate (PEFR), and use of salbutamol during the 2 months of the trial showed that control of asthma was equally good, irrespective of the device used to deliver active beclomethasone.

Complement changes during exercise-induced asthma

Two groups of asthmatic children, one with and one without a history of post-exercise wheezing, and one non-asthmatic adult, were exercised on a treadmill, and their complement levels were measured before and after exercise. The first group of patients had the most obvious fall in FEV 1 and all showed a slight rise in haemolytic complement following exercise. Two of the patients of the second group also had a rise in haemolytic complement. The C4 titre did not change in any of the asthmatic children who did not wheeze after exercise, but there were changes, albeit inconsistent, in the titres of C4 in four of the six patients who exhibited post-exercise wheezing. C3 breakdown products were not detected in any of the sera, following exercise. The role of complement in exercise-induced bronchospasm is not clear, but there does appear to be a greater lability of the complement system in patients who are susceptible to this form of provocation.

Use of exercise challenge to investigate possible tolerance to beta-adrenoceptor stimulation in asthma

The effect of prolonged salbutamol administration on beta-adrenoceptor function in asthma has been examined. Six adult patients received salbutamol tablets (16 mg daily) for between 4 and 20 weeks and six adolescents received salbutamol aerosol (800 microgram daily) for 2--5 weeks. Before and after the treatment period the acute bronchodilator response to inhaled salbutamol and the ability of inhaled salbutamol to protect against exercise-induced asthma were examined. Lymphocyte beta-adrenoceptor function was also measured in the patients on tablet therapy. Inhaled salbutamol was less effective in protecting against exercise-induced asthma at the end of the treatment period in the patients who had received tablet therapy, but otherwise there was no significant change in beta-receptor function of either airways or lymphocytes. This apparent loss of efficacy of inhaled salbutamol in the prevention of exercise-induced asthma in some subjects, even when its acute bronchodilator effect is preserved, might reflect differences in the susceptibility of different beta-adrenoceptors to desensitization after prolonged stimulation: its clinical importance remains uncertain.

Nebulised sodium cromoglycate in the preschool wheezy child

A double-blind controlled study of 14 preschool children with recurrent wheezing episodes was performed to show the effectiveness of nebulised sodium cromoglycate in inhibiting exercise-induced bronchoconstriction in this age group. All 14 children showed markedly less exercise-induced bronchoconstruction after nebulised sodium cromoglycate, 13 of them to a degree indistinguishable from results obtained in normal healthy children in the same age group. Nebulised water afforded protection from exercise-induced bronchoconstriction in some children. This study gives further evidence that sodium cromoglycate is an effective therapeutic agent in children under the age of 5 years.

Factors influencing mothers' compliance with a medication regimen for asthmatic children

This study lends support to the utility of a compliance-adapted health belief framework for exploring mothers' differential adherence to medication regiments prescribed for their asthmatic children. Most of the Model components behaved as hypothesized in predicting mothers' drug administration. The findings offer empirical evidence which can be applied to the purposes of identifying potential noncompliers and designating those specific, health-related orientations of the mother which are related to poor cooperation with therapy. Based on an educational diagnosis, the clinician may thus intervene to alter inappropriate health beliefs in order to enhance the likelihood of compliance for the asthmatic patient.

Clinical, physiological, and psychological study of asthmatic children attending a hospital clinic

The results of an investigation into the relationship between clinical, physiological, and psychological factors in 63 children with asthma are reported. The children were classified according to the severity of their asthma by reference to their regular drug usage and also were assessed in terms of the quality of control of the asthma and the degree of compliance with medication. Lung function tests and exercise tests were also carried out. Standard questionnaires to detect emotional or behavioural `deviance' in the children were completed by their mothers and by class teachers and assessments made of their personalities and the mental health of their mothers. Though the percentage of children with deviant scores on the questionnaire was high, it was not much greater than had been found among other (nonasthmatic) London children. Resting peak flow rate, measured as the mean of at least three tests on different clinical attendances, reflected the clinical grading of severity. Deviant children had lower levels of peak flow than non-deviant children, but their bronchial lability as measured by exercise-induced asthma was similar. Poor control of the asthma was associated with emotional or behavioural deviance, whereas deviance was independent of the severity of the asthma per se.

Exercise-induced bronchocontriction, skin sensitivity, and serum IgE in children with eczema

Forty-two children with eczema were studied for exercise-induced asthma (EIA), skin sensitivity to prick testing, blood eosinophil count, and immunoglobulins. 29 had a fall in peak expiratory flow rate after exercise greater than 20% and of these, 23 had symptoms of wheezing. 13 of the eczematous children showed a fall of less than 20%. The children with EIA showed greater cutaneous sensitivity (p less than 0.001) and a higher total serum IgE (p less than 0.025). 3 of the group with a fall of less than 20% had allergic rhinitis with skin sensitivity to grass pollen. The remaining 10 had no clinical evidence of allergic disease, other than eczema and skin sensitivity, and total IgE fell within the normal range. It is suggested that in a proportion of chilren with eczema there is little evidence of reaginic allergy.

A 12-month double-blind assessment of betamethasone valerate aerosol in the management of asthma

A double-blind trial of the topically active corticosteroid, betamethasone valerate in aerosol form, in the control of chronic asthma is reported. The results show that this is an extremely effective therapeutic agent in non-steroid dependent but nonetheless moderately severe asthmatics. Patients were well controlled on 800 mug of betamethasone valerate daily and control was maintained over a 12-month period. This form of treatment has few undersirable side effects but there is probably an increased incidence of oropharyngeal and laryngeal candidiasis. In particular, adrenocortical suppression was not noted.

Inhibition of exercise-induced asthma by different pharmacological pathways

Exercise-induced asthma (EIA) was provoked by standardized treadmill running for 6 minutes in 15 asthmatic children. The tests were carried out after the administration of a placebo, salbutamol, sodium cromoglycate, choline theophyllinate, and atrophine methonitrate aerosol in randomized fashion on different days. The mean post-exercise percent fall in peak expiratory flow rate was 45-2, 4-1, 19-6, 18-3, and 24-9 respectively. The proportion of children having significant amelioration of their EIA compared with those taking the placebo was 100% for salbutamol, 80% for cromoglycate and theophyllinate, and 60% for atropine. Salbutamol, choline theophyllinate, and atropine were bronchodilators at rest whereas cromoglycate was not, and the ability to suppress EIA was unrelated to bronchodilator effect. Even after bronchodilatation at rest, further broncho-dilatation occurred during the exercise period.

The place of cromolyn sodium in the long-term management of childhood asthma based on a 3- to 5-year follow-up

The long-term value of cromolyn sodium in the management of childhood asthma has been assessed over 3 to 5 years in 46 children with chronic perennial asthma who were not initially receiving corticosteroid therapy. The need to use steroids because of poor control during treatment with SCG was taken as a criterion of SCG treatment failure. Most such failures occurred early, but there were a few late treatment failures so that the proportion of SCG successes leveled of at 65% by the fourth and fifth years. Failure with SCG tended to occur in the younger children whose disease had progressed rapidly. By the fifth year, half of the children successfully treated by SCG had been able to discontinue use of the drug, and these children, but not the others, had diminished bronchial lability as shown on exercise testing.

Betamethasone 17-valerate in childhood asthma. A double-blind crossover trial in children not taking other corticosteroid therapy

A double-blind crossover trial of Betamethasone 17-Valerate steroid aerosol compared with placebo was carried out on 18 children with severe intermittent or chronic asthma. Seventeen of the 18 children showed a clinically obvious improvement on the active drug. The remaining child was unable to use the inhaler properly. In 14 children the response was dramatic. Improvement was shown at home by a reduction in the number of asthmatic symptoms, improvement in twice daily peak flow rates and by a lowered intake of sympathomimetic tablets. At monthly clinic visits, improvement was shown by chest examination, weight gain and by detailed respiratory function tests. By each of these criteria for improvement the benefit of Betamethasone 17-Valerate over the placebo was highly significant. There were no side effects attributable to the therapy and no evidence, as judged by short tetracosactrin tests, of adrenal suppression resulting from the drug. Betamethasone 17-Valerate appears to be a safe and effective therapy in children with severe asthma.

Exercise-induced asthma

A review of exercise-induced asthma is presented which describes work that has been carried out by the authors and by other investigators over recent years. The effect of exericse on lung function in asthmatic and normal subjects is compared. The influence of the type and severity of exercise on the response of the asthmatic is noted and the importance this has for interpretation of results. The effects of various drugs on exercise-induced asthma are considered in some detail. The clinical implications of the results of exercise tests in asthmatics, their relatives, and other subjects are considered in terms of the diagnosis and prognosis of asthma and its mode of inheritance. It is concluded that there is as yet no explantation for the mechanism of exercise-induced asthma, but it is a tool of potentially great value for research into the physiology and treatment of clinical asthma.

Beclomethasone aerosol in childhood asthma

Twenty children have been treated with the steroid aerosol beclomethasone, half of them in an open trial and the other half in a controlled cross-over trial. Children were assessed by means of clinical examination, diary records, and twice-daily peak flow rate measurements made at home. After 1 to 2 months all but 1 of the 16 children who were initially taking systemic steroids or corticotrophin were weaned off these drugs. The cross-over trial showed a significant improvement on the active drug, in terms of diary score, bronchodilator use, steroid dose, and twice-daily peak expiratory flow measurements. Adrenal function was entirely normal after 1 and 3 months on the drug as measured by morning cortisol levels and the response to tetracosactrin. There were no side effects, apart from the reappearance of hay fever or eczema in some children previously on systemic steroids. Follow-up for a mean of 4·5 ± 2·2 (SD) months showed the continuing efficacy of beclomethasone, though an increase in dose has been needed in some children. The advantages of aerosol steroid therapy in children are noted.

Use of serial exercise tests to assess the efficacy and duration of action of drugs for asthma

Silverman, M., Konig, P., and Godfrey, S. (1973).Thorax, 28, 574-578. Use of serial exercise tests to assess the efficacy and duration of action of drugs for asthma. A technique for studying the efficacy and duration of action of drugs used in asthma by means of exercise tests is described. The patient runs for six minutes every two hours, four times a day, on a treadmill at a constant speed and slope. The test drug or its placebo is given immediately before the first test of the day, and their effects on the exercise-induced asthma are compared. This enables the immediate protection and duration of action of the test drug to be measured. No change in the severity of post-exercise asthma was found when serial tests were performed during one day after administration of a placebo.

In a selected group of 14 children studied with disodium cromoglycate, three patterns were seen. In five patients the drug afforded prolonged benefit, in five others the protection was very short-lived, and in four patients it did not seem to be better than the placebo.

The use of the tests is also illustrated with respect to bronchodilator drugs.

Standardization of exercise tests in asthmatic children

Asthmatic children, known to be susceptible to exercise-induced bronchoconstriction, exercised by running or walking on a treadmill. Changes in airways obstruction were estimated by measurement of peak expiratory flow rate before, during, and after exercise. Post exercise bronchoconstriction reached a maximum when the duration of exercise was 6 to 8 minutes and when the gradient of the treadmill was 10 to 15%; exercise for longer periods or at steeper gradients produced no significant increase in bronchoconstriction. Bronchoconstriction was much greater after running than after walking at the same oxygen consumption in 4 out of the 5 subjects tested. The reproducibility of bronchoconstriction was good in individual patients when tests performed within one day or within one week were compared. Reproducibility diminished as the interval between tests increased to one month or one year. When tests were repeated at 2-hourly intervals throughout the day, no significant diminution in exercise-induced bronchoconstriction was noted. Variations in pre-exercise peak expiratory flow rate had no significant effect on exercise-induced bronchoconstriction in individual subjects. The range of response of normal children to treadmill exercise is defined and the value of the test in discriminating between asthmatic and other children is shown. If several tests are to be carried out by an individual patient, they should be performed on separate days at the same time of day and should be completed within one week. This will allow accurate comparisons to be made between tests in, for example, the assessment of the effect of different drugs in an individual patient.

Long-term trial of disodium cromoglycate and isoprenaline in children with asthma

A year-long double-blind trial was carried out in 53 asthmatic children with severe perennial symptoms who were not receiving corticosteroids or corticotrophin. The treatment group were given disodium cromoglycate with isoprenaline (Intal Co.) while the placebo group were given lactose with isoprenaline four times daily. The groups were closely matched for clinical, physiological, and immunological features. Evaluation was based on the use of a diary and clinical and physiological investigations, including exercise tests.After one year 71% of the treatment group were still well controlled while 76% of the placebo group had dropped out because of inadequate control of symptoms. There was no rise in the rate of failure towards the end of the trial period and there were no seasonal variations in the failure rate. No important toxic effects were noted. It was impossible to predict the outcome of the trial in any given patient from his clinical, physiological, or immunological status at the beginning. However, the prevention of exercise-induced asthma by premedication with disodium cromoglycate in a laboratory exercise test did correlate well with the satisfactory clinical response to the drug.

Exercise-induced bronchial lability in children with a history of wheezy bronchitis

Exercise tests were carried out on 18 children who had had wheezy bronchitis under the age of 5 years during hospitalization 7 years previously. A control group of 12 children who had been hospitalized with gastroenteritis at the same time were also studied. It was found that there was still a significant increase in bronchial lability among the wheezy bronchitis group compared with the controls, and this was especially obvious in the 7 children who had continued to have mild episodes of wheezing. It is suggested that the same abnormal mechanism operates in at least some cases of wheezy bronchitis as it does in asthma.

Time course of effect of disodium cromoglycate on exercise-induced asthma

Exercise tests, consisting of 6 minutes of continuous running, were performed on 10 asthmatic children known to develop exercise-induced bronchoconstriction. Disodium cromoglycate was equally effective in preventing post-exercise bronchoconstriction, whether given 20 minutes before or immediately before exercise. There was a small but significant effect when it was administered at the end of exercise. No placebo effect was noted. Bronchodilatation which occurred during exercise appeared to be enhanced when the drug was given immediately before exercise, but the maximum values of peak expiratory flow rate achieved during exercise were similar in all tests. In practice, no delay is therefore required between administration of disodium cromoglycate and the start of exercise, and the drug can be used in situations that might previously have demanded the use of bronchodilator aerosols for immediate effect.