Asthma, the most common chronic condition among children, is operationally defined as “recurrent wheezing and/or persistent coughing in a setting where asthma is likely and other rare conditions have been excluded.” Other definitions describe airway inflammation with eosinophilic and mast cell predominance, bronchial hyperresponsiveness, and reversible airflow limitation resulting in recurrent cough and wheeze. Wide mismatches still exist among children between disease severity and adequacy of treatment. Morris and Mellis used an evidence-based technique to answer three major questions about the management of childhood asthma.
First, they looked at the usefulness of adding a nebulized anticholinergic agent (ipratropium bromide) to nebulized beta-agonist therapy in the treatment of acute asthma in children. The main results showed that a single dose of a nebulized anticholinergic agent did not reduce the incidence of hospital admissions. In children with moderate to severe asthma, multiple doses, but not a single dose, of a nebulized anticholinergic agent reduced the rate of hospitalization by 25 percent. Lung function, measured by forced expiratory flow in one second, also improved with a multiple-dose regimen. There was no increase in adverse effects. The usefulness of treating children with mild to moderate asthma was less clear in terms of reduced hospital admissions, but lung function did show improvement.
The second question reviewed the effect of corticosteroid drugs on growth in children with persistent asthma. A systematic review of the effect of daily inhaled beclomethasone at 400 mcg demonstrated that it caused a linear reduction in growth rate. A recent study, however, demonstrated that children with asthma who had received a mean dose of inhaled budesonide at 412 mcg daily compared with control patients with asthma who had never taken inhaled steroids. A healthy control group demonstrated an initial reduction in growth rate during the first year of steroid use but no difference in final adult heights (as predicted from parental heights).
The third question reviewed the usefulness of a metered-dose inhaler with a spacer compared with a nebulizer in children with acute asthma. Outcome measures included rate of hospital admission, lung function, duration of stay in the emergency department, and rate of adverse events. Based on these measures, the usefulness of the inhaler and spacer was equivalent to that of a nebulizer. This finding confirms the effectiveness of a metered-dose inhaler with spacer as an effective medication delivery system in children with asthma.
In a related article, Sly and Flack discuss the utility of home monitoring of lung function in children with asthma using a portable peak expiratory flow (PEF) meter. They discuss studies demonstrating a poor correlation between PEF meter results and changes in lung function among children, a situation probably caused by multiple factors, including decreased compliance as time goes on and unreliability of recorded diary data. Self-management systems demonstrated to be effective in adults with asthma are effective using monitoring of either symptoms or PEF. The authors emphasize that there is no evidence that home monitoring of lung function by PEF or spirometry improves asthma management in children.
editor's note: Spacer devices decrease the diameter of aerosol particles, improving the pulmonary deposition of inhaled drugs. Spacers have different characteristics and may need to be used differently to optimize the result. Plastic spacer walls may increase electrostatism and decrease drug delivery. Using a metal spacer or washing the plastic spacer with a domestic detergent without rinsing with water or rubbing the walls avoids this problem. Small-volume spacers with inspiratory and expiratory valves may require more training for proper use. Facemasks are recommended only for the youngest users; all others should use a mouthpiece. Inhalation techniques should be checked at the physician's office to assure optimal treatment efficacy.
Self-monitoring of pulmonary function by use of a peak flow meter or a spirometer is a main part of self-management of asthma in adults. Efforts to duplicate similar success with self-management aided by the parents in children with asthma have been less successful. The percentage of correctly reported peak flow rates decreased from the beginning to the end of the study, with an increase in self-invented diary entries. These results were true whether or not the patients and parents were told that the measurements would be used to guide treatment changes. Clearly, if peak flow diaries are recommended in children with asthma, an electronic peak flow meter with the ability to record results should be used.—r.s.