Radiografía de tórax en la bronquiolitis: ¿es siempre necesaria?

Abstract

Background The routine use of chest radiograph in infants with bronchiolitis increases health costs and can often unnecessarily expose the patient to radiation. Objectives To evaluate the prevalence of infiltrate/atelectasis in infants younger than 2 years who presented to the emergency department with bronchiolitis, to assess whether patient management is changed after viewing the chest radiograph and to determine which clinical variables can accurately identify children with normal radiographs, with a view to reducing unnecessary radiological investigations. Patients and methods From October 2003 to December 2004, infants aged < 24 months evaluated in the emergency department of the Severo Ochoa Hospital (Madrid) with a diagnosis of bronchiolitis were included in this study. The variables registered were age, sex, time since onset, respiratory rate, temperature, asymmetry on auscultation, oxygen saturation and the virus identified. A chest radiograph was obtained and the need for admission was evaluated before and after obtaining the results. Results Two hundred fifty-two infants were included, of which 50 % were aged less than 5 months. Infiltrate/atelectasis was identified in 14.3 % (95% CI: 10.1-18.5; kappa coefficient: 0.64). Patients with infiltrate/atelectasis were 2.5 times more likely to have a temperature of ≥ 38 °C (p: 0.004), O2 saturation of < 94% (p: 0,006) and to be admitted before the results of chest radiograph were known. No differences were found between children with and without infiltrate in age at presentation, sex, disease duration, respiratory rate or identified virus. Patient management was modified in 30 % of patients with infiltrate/ atelectasis. Patients with a temperature of < 38° and O2 saturation of > 94% had a 92 % probability of normal chest radiograph. Conclusions Most infants presenting with bronchiolitis had a normal chest radiograph. Temperature ≥ 38° and O2 saturation < 94% were significantly associated with infiltrate/atelectasis. In most infants with bronchiolitis, the absence of fever and hypoxia are good predictors of normal chest radiographs.