"To Those in the Field"

EpiPens Aboard Boats

© 2002 Jeffrey E. Isaac, PA-C

Epinephrine Auto-injectors, a medical necessity

             In the last newsletter, I tried to talk you out of buying an AED (cardiac defibrillator) on the grounds that it’s considerable expense is not justified by the miniscule chance that it would do you any good in a cardiac arrest at sea. I also promised to suggest some items that are worth the money and time. The epinephrine auto-injector (Epi-pen) is one of them. You are far more likely to save a life with one of these.

             The EpiPen is a spring loaded hypodermic syringe designed to inject a therapeutic dose of the drug epinephrine into a patient suffering an acute, severe,  systemic allergic reaction. This life threatening medical emergency is  known as “anaphylaxis”, and develops as a result of the massive release of the chemical mediator histamine into the blood stream as part of the body’s over-zealous response to a foreign substance (known as an allergen). Allergens can be almost anything; peanuts, jellyfish toxins, lobster, bee venom, perfume…you name it, someone can be allergic to it. What’s really interesting is that up to 50% of patients presenting in anaphylaxis have no previous history of allergies. It comes as a complete surprise!

             Histamine, the culprit in anaphylaxis, causes bronchial constriction and vaso-dilation; that is, it constricts your airways and dilates your blood vessels. If the reaction is severe enough, the blood vessel dilation results in hives, swelling, and vascular shock. The swelling in the airways, along with the bronchial constriction, causes respiratory failure or arrest. This all can happen within minutes. No time for helicopters, medical textbooks, or radio medical advice. You must act immediately.

             Epinephrine (also known as adrenalin) is a bronchial dilator and a powerful vaso-constrictor. It can counter the effects of histamine within seconds of administration, saving the patient’s life. The Epi-pen is a nearly idiot-proof device for injecting the correct dose of epinephrine. The needle will penetrate wet suits and foul weather gear with ease. I’ve even fired them through quarter inch plywood in class demonstrations. Press it against the patient’s thigh; you can’t miss.

             Unfortunately, epinephrine is rapidly metabolized by the body, and only works for about 10 minutes. Therefore, an equally important part of the treatment of anaphylaxis is the immediate administration of an antihistamine (eg: Benedryl 50mg), by mouth. It takes about 20 minutes to take effect. You may need to administer a second or third dose of epinephrine if symptoms return before the antihistamine becomes effective.

             The Epi-pen is a single dose, single use item. You should carry three aboard, along with a supply of Benedryl capsules. You will need to learn the signs and symptoms of anaphylactic shock, and get a prescription and instructions from your medical practitioner. The whole process should take a fraction of the time you’ve devoted to learning CPR, and is a lot more likely to be useful.

             You will be annoyed, but not bankrupt by the price of the Epi-pen ($40-$60 each). You will also notice that the drug expires in less than 2 years. Realistically, it will last twice that long if you don’t freeze or cook it. In my opinion, this is a required emergency drug in your marine medical kit.