J.Mark FitzGerald

In recent years there has been concern regarding asthma management, with a number of studies identifying poor management. In addition, prevalence, and until relatively recently mortality, have been increasing in patients with asthma. In parallel with these developments has been the publication of a large number of asthma guidelines. Many deficiencies identified in earlier guidelines have been corrected in more recent publications - especially those using an evidence-based format. The critical problem of disseminating and implementing the guidelines remains. It appears that traditional continuing medical education will not lead to a change in clinical practice. The challenge remains to create a framework for implementing methodologically sound guidelines locally.

To compare the effect of bronchodilator delivery by use of a metered-dose inhaler (MDI) or wet nebulizer on objective measurements of acute airflow obstruction in adult patients. Published and unpublished research was identified by MEDLINE searches for articles published from 1966 to 1994, review of scientific citations, review of article bibliographies, communication with experts in the area of asthma therapy and aerosol delivery, primary investigators, and a manufacturer of spacer devices. Eighteen studies were selected from 159 potentially relevant articles by independent review in triplicate. Selection criteria included randomized trials that compared bronchodilator delivery by use of an MDI and wet nebulizer in adults with acute exacerbations of asthma or chronic obstructive pulmonary disease who were treated in an emergency department or a hospital. Data for patient characteristics, study setting, bronchodilator doses, outcomes, and methodological quality were independently extracted. Twelve studies with a total of 507 patients had sufficient data to calculate an effect size (in SD units) for improvement in airflow obstruction after bronchodilator delivery. All but 2 studies used spacer devices with the MDI. The overall treatment effect size was -0.02 (95% confidence interval [CI], -0.20 to 0.16) that favored the MDI, but the magnitude of the effect size was not clinically or statistically significant. No significant effect was observed in the subgroup analyses that compared the diagnosis: asthma, -0.17 (CI, -0.41 to 0.07) compared with chronic obstructive pulmonary disease, 0.23 (CI, -0.35 to 0.81); bronchodilator dose; or methodological quality. The results of a sensitivity analysis that included 5 of 6 excluded studies supported the findings from the primary analysis: 0.05 (CI, -0.11 to 0.20). Bronchodilator delivery by means of an MDI or wet nebulizer is equivalent in the acute treatment of adults with airflow obstruction. Spacer devices were used for bronchodilator delivery with an MDI in most studies and are recommended for the treatment of acute airflow obstruction. The choice of the delivery method will depend on the need for expedient treatment, availability of staff, consideration of costs, and findings from studies designed to evaluate treatment effects from larger than standard doses of bronchodilators delivered by use of an MDI.

OBJECTIVES: To characterize two cluster outbreaks of tuberculosis by DNA fingerprinting and to evaluate the possibility of their association with human immunodeficiency virus (HIV) infection and multiple drug‐resistant Mycobacterium tuberculosis.SETTING: Two clusters of tuberculosis cases in adjoining aboriginal Canadian reserves and a control population.METHODS: All cases of tuberculosis diagnosed in the two communities and a number of control isolates were fingerprinted using a novel simplified DNA‐based technique. Demographic data, purified protein derivative (PPD) skin test response to 5TU PPD, type of disease and HIV serology were also evaluated. Positive cultures were assessed for susceptibility to antituberculous drugs.RESULTS: Two distinct clusters with five cases in one community and 21 cases in the second were identified. Isolates from both communities differed in their DNA pattern but were identical within communities. Thirteen cases had bacteriologically proven disease and grew susceptible organisms. Serological analysis for HIV infection was carried out in 15 of 18 adults, and all were negative.CONCLUSIONS: The study shows the potential for the rapid transmission of tuberculosis infection in HIV‐negative subjects with susceptible organisms. It further highlights the usefulness of DNA fingerprinting for molecular epidemiology in evaluating particular outbreaks.