Wilderness and Rescue Medicine 8th Edition

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Wilderness and Rescue Medicine

For offshore situations or long evacuations, add- ing steroids such as dexamethasone or prednisone may suppress the inflammatory response associ- ated with the reaction. This will make a biphasic reaction less likely.

General Principles

Anaphylaxis Treatment WILDERNESS PROTOCOL

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Smaller People (< 30 kg):

• Epinephrine dose is 0.01 mg/kg. o Note: Autoinjectors are available in 0.1, 0.15, 0.3, and 0.5 mg versions. • Administer antihistamine (choose one) o Cetirizine dose:  2.5 mg for ages 2 to 5  5-10mg for age 6 and above, given once per day. o Diphenhydramine dose is 1 mg/kg • Dexamethasone dose is 0.6mg/kg; prednisone dose is 1 mg/kg. o Not to exceed adult dosage

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General Principles

Anaphylaxis Treatment WILDERNESS PROTOCOL

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Evacuation: • Transport with additional epi nephrine on hand . • Can be non-emergent if treatment was successful and vital signs return to normal . • Continue antihistamine as directed, if evacuation is delayed. o H2 antihistamines are not shown to add value in treatment of anaphylaxis. • Dexamethasone does not need to be repeated. If using prednisone, continue once per day up to 5 days if evacuation is delayed.

The patient in the photograph on the previous page approximately 12 minutes after the administration of epinephrine and diphenhydramine.

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Risk Versus Benefit The field treatment of anaphylaxis is a low-risk solution to a high-risk problem. You have a much better chance of saving a life with an injection of epinephrine than almost any other piece of medi- cal equipment you can carry. Furthermore, the drugs and dosages specified in the protocol are highly unlikely to produce an adverse outcome, even if the problem is misdiagnosed and the treat- ment turns out to be unnecessary.

© 2018 WMA

In the backcountry setting, it is advisable to carry at least three doses of epinephrine to cover biphasic reactions during evaluation and evacu- ation. Practitioners trained and comfortable with syringes and ampoules or vials may choose to carry epinephrine in that more economical and compact form. Epinephrine should be protected from light, freezing, and excessive heat. The epinephrine injection is often followed by an antihistamine, a type of drug that is believed to directly block the attachment of the hista- mine molecule to receptor sites on body tissues. Cetirizine and diphenhydramine are common examples. Either will take effect in about 15–20 minutes. Neither the epinephrine nor the antihistamine will actually remove the antigen or the histamine. It is possible to see a biphasic reaction with the reappearance of symptoms minutes to hours later. Because the effects of epinephrine are temporary, evacuation and medical follow-up should be planned.

General Principles

Anaphylaxis Wilderness Perspective

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High - Risk Problem: • Persistent abnormal mental status • Incomplete response to treatment • The patient is getting worse • Second injection of epi is needed

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© 2018 WMA