title: Oxygen saturation as a predictor of prolonged, frequent bronchodilator therapy in children with acute asthma.
abstract: OBJECTIVE
  To examine if the initial oxygen saturation (SaO2) in the Emergency Department is a useful predictor of prolonged frequent bronchodilator therapy (FBT) in children with acute asthma.
  
  
  METHODS
  Prospective cohort study of 273 children, 1 to 17 years of age, requiring systemic corticosteroids. Patients were categorized as needing FBT for >4 hours (n=166) versus >4 hours (n=107) and >12 hours (n=79) versus >12 hours (n=194). Multiple logistic regression determined the association between SaO2 and these outcomes.
  
  
  RESULTS
  Baseline SaO2 remains a significant independent predictor of FBT for >4 hours (OR=0.81) and >12 hours (OR=0.84); 91% of patients with SaO2 of 90% to 91% had FBT >4 hours and 80% of patients with SaO2 of < or =89% had FBT >12 hours. Children with SaO2 of < or =91% are 14.7 and 12.0 times more likely to require FBT for >4 hours and >12 hours, respectively, than those with SaO2 of 98% to 100%. The interval likelihood ratios for FBT >4 hours were 12.3 for SaO2 of < or =89%, 6.5 for 90% to 91%, but only 1.8 for 92% to 93%. The likelihood ratios for FBT >12 hours decreased from 9.8 for SaO2 of < or =89% to 3.5 for SaO2 of 90% to 91%.
  
  
  CONCLUSIONS
  SaO2 is a useful predictor of FBT >4 hours if it is < or =91% and of FBT >12 hours if it is < or =89%.
authors.affiliation: Division of Pediatric Emergency Medicine, The Hospital for Sick Children, University of Toronto, Canada.
authors.forename: Sanjay V
authors.initials: SV
authors.lastname: Mehta
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Parkin
authors.forename: Derek
authors.initials: D
authors.lastname: Stephens
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Keogh
authors.forename: Suzanne
authors.initials: S
authors.lastname: Schuh
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D001249:Asthma / Q000097:blood* / Q000188:drug therapy; D001785:Blood Gas Monitoring, Transcutaneous; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010100:Oxygen / Q000097:blood*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D001993:Bronchodilator Agents; D010100:Oxygen