Cardiovascular responses in patients with acute allergic reactions treated with parenteral epinephrine

The present study describes the cardiovascular responses to epinephrine (Epi) given into the arm, in adult patients with acute allergic reactions, and the differential responses to subcutaneous (SC) and intramuscular (IM) administration. Sixty-three adult patients were treated with Epi administered SC or IM after H1 and H2 receptor blockade. Heart rate and blood pressure (BP) were then measured for 20 minutes. Changes in heart rate and BP variables were analyzed. Pulse pressure and systolic BP showed increases with time. Diastolic BP also showed a modestly decreasing values over time. Heart rates did not change. Time-related changes between IM and SC Epi treatment were not observed. Sex influenced timed BP values and a significant sex by time effect was observed. In subset analysis, only male patients showed an overall time effect for BP variables, especially pulse pressure. In conclusion, adults with acute allergic syndromes treated with arm-injected Epi show a modest but definite increase in pulse pressure and systolic BP. This pattern is observed more in males. Heart rate and blood pressure differences between IM and SC arm-injected Epi treatments do not appear to be significant.