Gail is receiving her first dose of postoperative IV Gentamicin.
On examination, Gail is alert oriented and anxious, she appears flushed and short of breath. HR 96, BP 95/50, Resp rate 28/min SpO2 93%. She has bilateral wheeze on auscultation.
What are you worried about and what needs to be done?
Gail is showing signs of anaphylaxis with exposure to a known allergen. First line management includes removing the allergen (STOP the Gentamycin and remove the infusion line DO NOT remove the IV cannula) and administration of 500 mcg IM adrenaline, this should be administered via deep intramuscular injection into the lateral aspect of the thigh.
The key to managing anaphylaxis is the rapid recognition and early administration of IM adrenaline to stop the inflammatory cascade of mast cells releasing histamine and prostaglandins. The release of histamine and leukotrienes produce a state of vasodilation and increased vascular permeability with fluid shifting from the the intravascular space to the interstitial space leading to oedema and hypovolaemia related hypotension. Bronchoconstriction occurs from the release of prostaglandin and protease so clinically we will start to see an increased work of breathing, wheeze, laryngospasm and hypoxaemia.
In all instances, IM adrenaline is the first line treatment for anaphylaxis, it causes vasoconstriction and bronchodilation and helps to reverse the effects of oedema created by increased vascular permeability seen in response to histamine release from the allergen. Antihistamines are not recommended as first line treatment for anaphylaxis.
Gail should also be positioned flat in the bed or if too short of breath, sitting upright with legs extended not dangling down. Gail should not be allowed to stand or walk. Oxygen therapy should be commenced. Fluid resuscitation may need to be commenced and a second dose of IM adrenaline administered.
Some important take home messages about Adrenaline use in anaphylaxis:

References:
https://www.allergy.org.au/images/ASCIA_HP_Guidelines_Acute_Management_Anaphylaxis_2021.pdf
Susan is the Head of Nursing Education for the Medcast Group.
DipAppScNsg, BN, CritCareCert, CoronaryCareCert, TraumaNsgCareCert, CertIV(TAE), MN(Ed), and GradCert(Ldrshp & Mgt).
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