Prehospital Epinephrine Reduces Odds of Biphasic Reaction and Reduces Time in Emergency Department

In a recent study published in the Annals of Allergy, Asthma & Immunology, researchers sought to assess the impact of the prehospital administration of epinephrine on the outcomes of adults and children suffering anaphylaxis.

The study looked at the outcomes of 1,107 patients who arrived at an emergency room from April 2008 to December 2022. Their median age was 29; 53.6% were female, and 33.1% were younger than 18.

The researchers compared the incidence of biphasic reactions, length of stay in the emergency department, and admissions to the hospital among those who received epinephrine prior to arrival at the emergency department to those that did not.

A biphasic reaction is defined as the recurrence of anaphylaxis symptoms within 72 hours of the initial anaphylactic event without re-exposure to the trigger.

They found that prehospital administration of epinephrine cut the odds of experiencing a biphasic reaction by 41% (5.4% vs 9.3%) and decreased the median length of stay (LOS) in the emergency department (ED) by 15% from 4.7 to 4.0 hours. They found no difference in hospital admissions between the two cohorts.

Their research led them to draw the following conclusion:

Prehospital epinephrine administration reduced the odds of a biphasic reaction and decreased ED LOS but did not reduce hospitalization in this cohort of ED patients who had anaphylaxis. Our findings suggest that timely administration of prehospital epinephrine is associated with improved patient outcomes.

A reminder that epinephrine is the only drug that can halt and reverse the progression of anaphylaxis, but it can’t help you if you don’t have it on hand when you need it. Take two emergency epinephrine devices with you everywhere, every time, and be sure to administer the first when you first suspect anaphylaxis.