Failure of oxygen saturation and clinical assessment to predict which patients with bronchiolitis discharged from the emergency department will return requiring admission

Objective. To determine if there is a difference between patients with bronchiolitis who are discharged from the emergency department (ED) but return requiring admission and those who do not return. Design. Retrospective, case control study. Setting. Tertiary care children's hospital emergency department. Participants. Fifty-seven study patients under one year of age with bronchiolitis seen from November 1991 to April 1993 who were discharged but returned requiring admission within 96 hours, and 124 controls, matched by diagnosis, who did not return. Results. No differences were found between cases and controls in duration of illness (3.0 vs 3.7 days, P = 0.08), gestational age (39.3 vs 38.8 weeks, P = 0.32), chronologic age (20.9 vs 22.9 weeks, P = 0.31), respiratory rate (49.9 vs 48.0 respirations/min, P = 0.18), presence of retractions (54.8 vs 54.4%, P = 0.97), oxygen saturation (SaO₂; 97.6 vs 98.0%, P = 0.29), or number of nebulized β-agonists administered in the ED (1.4 vs 1.2 P = 0.35). Cases had higher mean heart rates (HR) than controls (154.8 vs 148.8, P = 0.006). Patients with HR >150 were more likely to return requiring admission (odds ratio = 2.45, 95% confidence intervals 1.2-4.9). However, only 36 of 57 patients who returned requiring admission had HR >150 (sensitivity = 0.63), and 73 of 124 who did not return had HR ≤ 150 (specificity = 0.59). None of the returns required admission to the intensive care unit, and their mean duration of admission was 59 hours. At the time of admission the cases had lower SaO₂ (95.9 vs 97.7%, P = 0.001) and a higher frequency of retractions (83.3 vs 52.6%, P = 0.02) than when seen initially. Conclusions. Oxygen saturation and clinical assessment failed to differentiate between patients with bronchiolitis who returned requiring admission and patients who did not return.