13 Oxygen Saturation as a Predictor of Prolonged, Frequent Bronchodilator Therapy in Children with Acute Asthma

To examine if initial transcutaneous oxygen saturation (SaO2) in the Emergency Department (ED) is a useful predictor of prolonged frequent bronchodilator therapy (FBT) in children with acute asthma.

Prospective cohort study of 273 children 1–17 years requiring systemic corticosteroids. Patients were categorized as needing FBT for >4 hours (n=166) versus less (n=107), and >12 hours (n=79) versus less (n=194). Multiple logistic regression determined the association between various levels of SaO2 and these outcomes.

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 90–91% had FBT >4 hours, and 80% of patients with SaO2 <90% had FBT >12 hours. Children with SaO2 <92% are 14.7 and 12.0 times more likely to require FBT for >4 hours and >12 hours, respectively, than those with SaO2 of 98–100%. The interval likelihood ratios (LR) for FBT >4 hours were 12.3 for SaO2 <90%, 6.5 for 90–91%, but only 1.8 for 92–93%. The LR for FBT >12 hours decreased from 9.8 for SaO2 <90% to 3.5 for SaO2 of 90–91%.

SaO2 is a useful predictor of FBT>4 hours if it is <92%, and >12 hours if it is <90%.