Objective: To evaluate the utility of pre- and posttreatment O2 saturation (SpO2) for prediction of admission or relapse after ED release in acute asthma exacerbations using a standardized treatment protocol.
Design: A prospective, double-blind, observational study was performed at a pediatric ED. Children with acute asthma were enrolled upon ED presentation. SpO2 was measured prior to treatment and after disposition decision. Two experienced physicians determined disposition based on history and physical examination alone, while blinded to SpO2. Relapse of released patients was determined by telephone follow-up.
Results: A pretreatment room-air SpO2 of < or = 91% had a sensitivity of 0.24, a specificity of 0.86, and a likelihood ratio of 1.77 to predict admission/relapse. A posttreatment room-air SpO2 of < or = 91% had a sensitivity of 0.34, a specificity of 0.98, and a likelihood ratio of 16.43 to predict admission/relapse.
Conclusions: As opposed to some previous studies, this study found pretreatment SpO2 to be a relatively poor predictor of admission. A posttreatment SpO2 of < or = 91% occurred in a minority (32%) of patients, but increased the odds of admission 16-fold and may be used as an adjunct to objectively confirm the need for admission.