Protocol 6: Anaphylaxis + Epinephrine
Anaphylaxis is an allergic reaction that has life-endangering effects on the circulatory and respiratory systems. Typically an almost immediate, rapidly progressive multi-system allergic reaction occurs when a foreign protein is introduced into the body. These proteins can be introduced via injection (stinging & biting insects, snakes, sea creatures, etc.), ingestion (food, chemicals, medications, etc.), absorption, or even inhalation.
Early recognition and prompt treatment of anaphylaxis, particularly in a wilderness setting, is essential to preserve life. The onset of symptoms usually follows quickly after an exposure (minutes after a sting or bite, within 30-60 minutes following ingestion). Over 20% of all anaphylactic reactions are biphasic reactions, meaning the swelling of the airway can reoccur within one to 72 hours after the original attack.
In addition to shortness of breath, weakness and dizziness, persons suffering from anaphylaxis may also show signs of anxiety, coughing, chest tightness, trouble swallowing (and throat itchiness), abdominal cramps, or generalized itching.
Physical findings may include a rapid heart rate, low blood pressure (faint or absent distal pulses), and other evidence of shock, upper airway obstruction (stridor) and lower airway obstructions (wheezes) with labored breathing, generalized skin redness, hives, and swelling of the mouth, face, and neck.
Epinephrine should only administered to patients having positive symptoms of an acute systemic reaction (i.e. generalized skin rash, difficulty breathing, fainting, or facial swelling). Anaphylaxis is a LIFE-THREATENING EMERGENCY.
Inject 0.01 mg/kilogram (up to 0.5 mg) of 1 mg/ml solution of epinephrine intramuscularly (IM) into the lateral mid-thigh. A dose of 0.3 to0.5 mg is appropriate for the average adult (pre-loaded in an EpiPen for example).
Maintain an open airway and position of comfort (most likely sitting up). Initiate either positive pressure ventilations (PPV or rescue breathing) or full cardiopulmonary resuscitation (CPR) as indicated. If the airway is completely or nearly completely swollen and the airway is occluded, CPR will be unsuccessful.
Repeat epinephrine injections as soon as every 5 minutes if needed.
Administer an antihistamine by mouth. Recommended OTC medications include 25-50 mg of diphenhydramine HCl (Benadryl) every 4-6 hours for the average adult, or 2 tablets each of Pepcid AC and Zyrtec (taken together).
Consider prednisone 60 mg/day for an average adult.
|Evacuate quickly to definitive care if safe to do so. Consider an ALS intercept if airway remains compromised.|
|If evacuation is not possible, monitor carefully for biphasic reaction. Repeat treatment per protocol as necessary..|
* There is 1 mg of epinephrine in 1 ml of epinephrine 1/1000; there are 0.3 mg in 0.3 ml of 1/1000. Pre-loaded commercially available injectors deliver either 0.3 mg (standard adult dose) or 0.15 mg (standard pediatric dose). If the person weighs less than 66 lbs (30 kg), the doses are: epinephrine is 0.01 mg/kg; diphenhydramine is 1mg/kg; and prednisone is 1 - 2mg/kg. When using lbs, multiply the weight times 0.45 to get the weight/mass in kilograms.
NOTE TO CONSULTING PHYSICIAN:
The organization will need a prescription from you to obtain injectable epinephrine. It is available in the following forms: AdrenaClick, EpiPens, AUVI-Q and manual injection methods. Over the counter diphenhydramine should always be carried in addition to injectable epinephrine. An epinephrine auto-injector (such as an Epipen) is preferred. The AUVI-Q epinephrine auto-injector device that was recalled and discontinued in November 2015 due to a failure rate of >30%, has been re-introduced as of 2018 and now has the same failure rates as the EpiPen (.03%).
Last Updated: Nov. 2019
These protocols were written by Jeffrey Isaac, PA-C (of Wilderness Medical Associates International) and have been edited and authorized by the executive medical and curriculum directors Kathryn Vaughn, MD, FAWM & Jennifer Kay, RN, BNS, CCRC, CCRP, WALS, for use by Center for Wilderness Safety, Inc.