Our study population was comprised of 200 children who presented to the ER of the Hospital for Sick Children, Toronto, between September and December 1988, for the treatment of acute asthma when one of the investigators was available. Children with acute bronchiolitis or with complicating pulmonary or cardiac disorders were excluded from the study.
On arrival to the ER, the following historic data were obtained from the parents of each subject: age, sex, duration of present episode, number of previous hospital admissions, and current . Prior to treatment and on disposition from the ER, one of the investigators performed a physical examination and measured pulmonary function and SaOs. From the physical assessment, a clinical score was assigned for each patient (Table 1). This clinical score is a modification of the Fischl scoring system. Dyspnea was defined as the investigators impression of the degree of the child’s breathlessness. A respiratory rate above 95 percent confidence limits” for age was assigned a score of 1. Since it was not possible to measure pulsus paradoxus in some of our younger patients, the score was standardized by expressing the number of positive values (score = 1) for an individual patient, as a fraction of the total number of variables measured for that patient. The final score ranged from 0 to 1.0, increasing with severity. Pulmonary function was measured by a portable spirometer in children over seven years of age who were able to perform spirometry reliably. FEVt, FVC, and PFR were measured in triplicate, the maximal values were accepted, and expressed as a percentage of the predicted value for height and sex.
Table 1—Clinical Scaring System
|Score = 0||Score = 1|
|Respiratory rate*||<2SD for age||^2SD for age|
|Pulsus paradoxus||<15 mm Hg||^15 mm Hg|
|Dyspnea||Absent or mild||Moderate or severe|
|Accessory muscle use||Absent or minimal||Moderate or severe|
|Wheezing||Absent or end expiratory only||Throughout expiration or expiratory + inspiratory|