Allergic Reactions and You Dana Daidone D.O.

Onset of Reaction Usually within minutes after injection 80% occur on induction 15% during maintenance 5% in recovery In the case of delayed rxn, think about latex or volume expanding fluids

Most Common Symptoms Urticaria Difficulty ventilating – difficulty breathing Decreased pulse ox Decreased ET CO2 Hypotension or cardiac arrest ‘sense of doom’ reported by patient

In 27% of pts., features may be isolated Hypotension only Cardiac arrest only Bronchospasm only In the cases without cutaneous signs, practitioners were less likely to think of the possibility of anaphylaxis This delays specific dx. and tx.

Causes of anaphylaxis Data from past 25 years – 5700 cases #1 MUSCLE RELAXANTS cases #2 latex – 900 cases #3 abx. – 350 cases (pcn) #4 hypnotics – 300 cases (propofol, tpl) #5 colloids – 200 cases #6 opoids – 100 cases (mso4, demerol)

#1 offender – MUSCLE RELAXANTS SUCC – 1500 cases VEC – 1000 cases Atracurium – 500 cases Rocuronium – 400 cases Pancuronium – 250 cases

How to treat Fluids – 100% fiO2 – turn off agent IV epi 1ucg/kg – repeat and double dose prn Hydrocortisone – inhibits mediator release Benadryl – H1 receptor blocker Ranitidine – H2 blocker – DON’T FORGET THIS DRUG.

H-2 blockade is good There is no evidence that administration of H-1 blockade without H-2 blockade reverses the course of anaphylaxis once the mediators in the cascade have been liberated. H-1 blockade will ‘ease’ some of the sxs, but ultimately you need EPI and H-2 blockade.

Don’t forget H-2 blockade There have been several cases where high dose epi, benadryl,steroids and fluids had been given to no avail for an anaphylactic reaction. It was only until someone remembered to give zantac did the pt. turn around….

Vasopressin for anaphylactic shock ? Anaphylaxis is a form of vasodilatory shock and we now know that vasopressin can be beneficial in these situations when epi is not. Pt. had a rxn. to infused colloid, still in shock after appropriate tx, given a one time dose of 2 U vasopressin for hemodynamic stability. Epi only partially reverses histamine induced vasodilatation – vasopressin appears to do this better.

Lastly, During the crisis, get an a-line and draw blood. It’s important for diagnosis to draw labs for histamine levels, tryptase levels, and IgE levels.