5. ANAPHYLAXIS Flashcards
Why IM Epinephrine?
The pharmacologic actions of epinephrine address the pathophysiologic changes that occur in anaphylaxis better than any medication. Therapeutic actions of epinephrine affect the different Autonomic receptors: A-1 receptor: vasoconstriction, inc. peripheral vascular resistance, inc. blood pressure, decreased mucosal edema; B-1 receptor: inc. heart rate (chronotropy), inc. force of cardiac contraction (inotropy); B-2 receptor: dec. mediator release from mast cells and basophils, inc. bronchodilation
How to administer IM epinephrine?
Recommended Route of Administration is IM on the VASTUS LATERALIS. Dosing would be an aqueous dilution of 1:1000 at 0.01 mL/kg, maximum of 0.5 mL per dose. IM epinephrine MAY BE REPEATED at 5 to 15 minutes intervals if there is no response or even sooner if clinically indicated.
After Epinephrine what other measures can we do?
Positioning, Airway and O2, Fluids, Monitoring (severe hypotension shock), Adjunctive Agents H1 Blockers, H2 blockers, Glucocorticoids
H1 Blockers are mainly used in anaphylaxis to _________ they dont reverse _________ GIVE DOSAGE
mainly used to relieve pruritus and urticaria; does not relieve airway obstruction, hypotension or shock. Diphenhydramine 50 mg/IV over 5 minutes or 1 mg/kg/IV over 5 minutes in children
H2 receptor antagonists are used to? Dosage?
used to decrease gastric acid output, decrease vasodilation and mucus gland secretion. ADULTS: Ranitidine 50 mg in 20 mL fluid IV over 5 minutes. CHILDREN: Ranitidine 1 mg/kg in 20 mL fluid IV over 5 minutes.
What are glucocorticoids for?
Glucocorticoids may also be given. However, the onset of action of glucocorticoids take several hours. Therefore, these medications do not relieve the initial symptoms and signs of anaphylaxis. Rational for giving them is theoretically to prevent biphasic reactions METHYLPREDNISOLONE 1-2 mg/kg/day
What if patient is on B blockers? And they can be resistant to epinephrine
GLUCAGON 5 mg/IV over 5 minutes - inotropic and chronotropic effects not mediated through B receptors
Who to send home? Who to admit?
Most patients with minor signs and symptoms who show marked resolution with ER treatment can be sent home with regular oral antihistamines and follow-up instructions. Those who present with life-threatening anaphylaxis should be admitted and observed for another 24-48 hours even if their symptoms were easily managed or reverse because of high risk of late phase reactions
How to prevent?
Avoidance of known allergen altogether
Advise patient to keep an ADRENALINE KIT (EPIPEN) and instruct how and when to use it
Venom immunotherapy for insect allergic individuals
Criteria
- Skin + respi ssx or hypotension
- 2 or more sa skin, cardio, lungs, GI after exposure
- > 30% drop in systolic bp or patient’s baseline
