THE IMPORTANCE OF SPIROMETRY IN THE ASSESSMENT OF CHILDHOOD ASTHMA

Objective.-To assess the pulmonary function of children with asthma at the time of a routine follow-up visit when they were judged to be clinically well. Design.-Pulmonary function tests were performed on children with a previous diagnosis of asthma. None had had any symptoms for at least 6 weeks. All had normal Wright peak flow rates and normal findings at physical examination. Setting.-General pediatric and pediatric pulmonary clinic at a municipal hospital in the Bronx, NY. Patients.-Sixty-five children with asthma who fit the above criteria. All were able to perform spirometry adequately. Their mean (+/-SD) age was 11+/-3 years, and their median age was 10 years. Selection Procedures.-All clinic patients were screened as possible participants. The 65 patients were deemed eligible, and were willing and able to perform spirometry. Interventions.-None. Measurements and Results.-The group's mean (+/-SD) forced expiratory volume in 1 second/forced vital capacity ratio was 80%+/-8%, and their mean mid-maximal expiratory flow was 66%+/-23% of the predicted value. Of the 65 patients, 11 (17%) had forced expiratory volume in 1 second/forced vital capacity ratios of less than 72%, and 35 (54%) had a mid-maximal expiratory flow of less than 65% of the predicted value. Conclusion.-Failure to perform spirometry in children with asthma results in underdiagnosis of airflow obstruction. This may result in obstruction persisting into adulthood and/or progression to hyperinflation.