Page 106 - 2022 Ranger Medic Handbook

Anaphylaxis Reaction Emergencies
Anaphylactic shock is a life-threatening medical emergency that is caused by a generalized allergic reaction affecting
the cardiovascular, respiratory, cutaneous, and gastrointestinal systems. It is a severe immune-mediated reaction that
occurs when a previously sensitized patient is reexposed to an offending allergen such as: bee/wasp stings, penicillin
or other drug allergies (especially when given IM/SC/IV), seafood (especially shrimp/shellfish), and nuts of various types.
Allergens may produce an allergic reaction by being ingested, inhaled, injected, or absorbed through the skin/mucous
membranes. Shock is produced by the release of histamine that causes “leaky” vessels resulting in hives/edema and
hypotension; it also causes bronchospasm/wheezing. This produces both a volume problem and a vascular resistance
problem. Anaphylactic shock differs from less severe allergic reactions in that it is characterized by hypotension and
obstructed airflow (upper and/or lower) that can be life-threatening.
SECTION 3 Signs/Symptoms
S/Sx: Wheezing (bronchospasm), dyspnea, stridor (laryngeal edema), angioedema, urticaria (hives), hypotension, tachy-
cardia. Clinical observation is the only diagnostic test. Use rapidity of onset and constellation of symptoms to suggest
the diagnosis. A prior history of similar symptoms may be the only other clue. Observe closely with frequent assess-
ment/reassessment of mental status, vital signs, and pulse oximetry. Anaphylaxis is likely if ANY of the following three
criteria are met:
■ Acute onset (minutes to several hours) with involvement of skin and or mucosal tissue (hives, pruritus, swollen lips/
tongue) plus 1 of the following: respiratory compromise (e.g., dyspnea, wheezing, stridor or other signs of broncho-
spasm) or cardiovascular compromise (eg, decreased blood pressure, syncope).
■ Two or more of the following that occur quickly (minutes to several hours) after exposure to a likely allergen: involve-
ment of skin-mucosa, respiratory compromise, reduced blood pressure, persistent GI symptoms (e.g., vomiting,
abdominal pain).
■ Reduced blood pressure (systolic < 90 for adult) after exposure to a known allergen for the patient.
Initial Management & Extended Management
For patients with S/Sx of airway involvement and/or circulatory collapse:
Epinephrine is the mainstay of therapy. Administer Epi-Pen OR epinephrine 0.3–0.5mg (0.5mL of 1:1,000 IM into the
anterolateral thigh. DO NOT USE INTRAVENOUSLY. Repeat epinephrine q5min prn. Administer oxygen with pulse
oximetry monitoring. If severe respiratory distress exists, aggressive airway management with bag-valve-mask and
airway adjuncts (oral and nasopharyngeal airways). Control airway early if no response to epinephrine. IV normal saline
TKO (saline lock). Administer diphenhydramine 50mg IV/IM/PO/SL. Administer 1–2L crystalloid bolus for hypotension
then titrate to establish systolic blood pressure > 90mmHg or palpable radial pulse if BP cuff not available. Administer
dexamethasone 10mg IV/IM/PO. If wheezing is present after epinephrine administration, consider Albuterol, 2–3 puffs
q5min, repeat up to 3 times. The metered dose inhaler works best when used with a spacer (e.g., rolled up piece of
paper, cardboard from toilet paper roll, etc.). Administer famotidine 20mg PO bid.
Considerations
Immediate definitive airway if impending airway obstruction from angioedema is suspected. Delay may lead to complete
obstruction, difficult intubation and cricothyroidotomy. Give 6–8L O 2 /min via face mask if required or up to 100% if
airway controlled. Albuterol metered dose inhaler (2–3 puffs) for bronchospasm. Place patient in recumbent position
and elevate lower extremities.
Crystalloid (saline) fluid bolus IV titrated to restore and maintain blood pressure. Monitor patient: at least 24 hours fol-
lowing treatment: Recurrence of symptoms may occur in up to 20% of patients (generally within 8 hours but recurrences
up to 72 hours following initial resolution of symptoms have been reported).
Apply ice to and consider injecting small dose of epinephrine (0.1–0.2mL 1:1,000) into the injection site unless contra-
indicated. If due to bee/wasp sting(s), carefully remove all stingers. Avoid applying pressure to venom sac while stinger
is inserted in patient.

92 SECTION 3 TACTICAL MEDICAL EMERGENCY PROTOCOLS (TMEPs) & SICK CALL