Anaphylaxis

Question 1

Define perioperative anaphylaxis and the grades of anaphylaxis (2)

Answer 1

Perioperative anaphylaxis is a life-threatening reaction that happens suddenly, without warning and can affect anyone.

-Grading is determined by signs present in the patient and ranges from 1-5

• Grade 1-2 are hypersensitive reactions but not severe enough to be classified as anaphylactic
• Grades 3-5 are included as anaphylactic reactions.

Question 2

2 Describe the pathophysiology of anaphylaxis (2)

Answer 2

Anaphylaxis is an IgE-mediated type 1 hypersensitivity reaction.
It involves the massive release of inflammatory markers from basophils and mast cells.

Question 3

List the most likely perioperative anaphylaxis triggers (3)

Answer 3

1. Antibiotics
2. NMB drugs and reversal agents
3. Chlorhexidine
4. Blue dye (patent blue)

Question 4

4. Describe the key signs of perioperative anaphylaxis grade 3 and above
   in adults (2)

Answer 4

GRADE 3 = is characterised by a more severe hypotension, bronchospasm and may
include airway swelling

GRADE 4 = is characterised by indications for performing CPR.

GRADE 5= is a fatal reaction.

Question 5

What are the commonest presenting features of perioperative anaphylaxis in children? (2)

Answer 5

Bronchospasm/ high airway pressures
Hypotension
Tachycardia

Question 6

Why is the incidence and management of anaphylaxis in the operating theatre likely to differ to that in other locations? (2)

Answer 6

Anaphylaxisis symptoms may not be obvious, as patients are often covered in drapes and unconscious, making them unable to communicate and therefore anaphylaxis is diagnosed later.

Also, perioperatively multiple drugs are given to the patient at once usually through IV so anaphylaxis reactions progress more quickly.

Question 7

Outline the management of perioperative anaphylaxis grade 3 and above giving your rationale for treatment (4)

Answer 7

-Halt surgery and call for help
-Call for cardiac arrest trolley and anaphylaxis treatment pack

-There should be early administration of Adrenaline as soon as anaphylaxis is suspected (usually IV in perioperative settings) to stop it from getting worse.

-Give 100% oxygen and ensure adequate ventilation due to airway compromise

-Rapid IV crystalloid fluid challenge of 20ml/kg large volumes of IV fluids – to restore the circulating blood volume and cardiac filling

-Elevate patients’ legs if hypotension

-ALS protocol should be followed in cardiac arrest or if systolic BP is less than 50

Question 8

8. Why might the incidence of anaphylaxis differ in the obstetric patient population? (2)

Answer 8

The immune changes in pregnancy to prevent the foetus from being rejected as a foreign
Body.

Increased progesterone levels in pregnancy increase the risk of anaphylaxis.

Question 9

What are the key presenting signs of perioperative anaphylaxis in the awake Caesarean section patient with central neuraxial blockade?

Answer 9

Main Symptom: New onset hypotension +/- patient reports feeling unwell prior to onset of hypotension

However cutaneous and respiratory manifestations are also common

Question 10

Does Leanne love you

Answer 10

yes!