Predictors of repeat epinephrine administration for emergency department patients with anaphylaxis

BACKGROUND: Risk factors that predict which patients with anaphylaxis might require repeat doses of epinephrine are poorly understood. OBJECTIVE: The objective of this study was to identify risk factors associated with the need for multiple doses of epinephrine during an anaphylactic reaction. METHODS: Patients were included if they met diagnostic criteria for anaphylaxis on presentation to the emergency department (ED) at our academic medical center between April 2008 and February 2014. Data were collected on allergic history, presenting signs and symptoms, anaphylaxis management, and disposition. Univariable and multivariable analyses were performed to estimate associations between possible risk factors and the need for multiple doses. RESULTS: Of 582 ED patients with anaphylaxis, 45 (8%) required multiple doses of epinephrine. By multivariable analysis, factors associated with the need for repeat doses were a history of anaphylaxis (odds ratio [OR], 2.5 [95% CI, 1.3-4.7]; P =.005), the presence of flushing or diaphoresis (OR, 2.4 [95% CI, 1.3-4.5]; P =.007), and the presence of dyspnea (OR, 2.2 [95% CI, 1.0-5.0]; P =.046). Patients who received more than 1 dose were more likely to be admitted to the general medical floor (OR, 2.8 [95% CI, 1.1-7.2]; P =.03) or intensive care unit (OR, 7.6 [95% CI, 3.7-15.6]; P <.001). CONCLUSION: Patients with a history of anaphylaxis, flushing or diaphoresis, or dyspnea may require multiple doses of epinephrine to treat anaphylactic reactions. Patients who require more than 1 dose are more likely to be admitted to the hospital, thus increasing health care resource utilization.