Anaphylaxis

Question 1

What signs may indicate a patient is developing an anaphylactic reaction while under anaesthesia?

Answer 1

1. Mucocutaneous - Erythema, Urticaria, Angioedema
2. Respiratory - Bronchospasm, cough, hypoxia, inc airway pressure
3. CVS - Hypotension, tachycardia, arrythmia, CVS collapse, arrest

Question 2

What is the usual timeframe for development of anaphylaxis?

Answer 2

Usually immediate, but can be delayed by 30-60mins

latex allergy is often delayed

Question 3

Outline the immediate management of anaphylaxis

Answer 3

1. Call for help
2. Delegate someone to get - crash trolley and anaphylaxis kit
3. Cease all suspected triggers
4. Check ECG - commence CPR if losing cardiac output
5. Intubate, reduce volatile, give 100% O2
6. Infuse fluids, elevate legs and insert IAL
7. Give adrenaline - 1mcg/kg bolus 1-2mins PRN
8. If signs persist - start adrenaline infusion -> pt requires a CVL
9. Consider adjuncts ONLY when haemodynamics are stable
10. Collect blood for tryptase levels
11. Contact ICU

Question 4

What are the IV and IM adrenaline bolus doses for anaphylaxis?

Answer 4

1. IV 0.25-1mcg/kg
2. IM Adult 500mcg
   
   1. 6-12 300mcg
   2. <6 150mcg

Question 5

How is an IV adrenaline infusion set up?

Answer 5

3mg of Adrenaline in 50mLs of 5% dextrose or 0.9% NaCl - mLs/hr = mcg/min

Commence at 7mLs/hr

Question 6

How would you manage severe bronchospasm?

Answer 6

1. In circuit bronchodilators - Salbutamol, Ipratropium
2. Salbutamol IV bolus (15mcg/kg upto 250mcg)
3. Magnesium 50mg/kg over 20mins - max dose 2gm
4. Hydrocortisone 1-2mg/kg IV

Question 7

What other drug options are available for patients poorly responsive to Adrenaline?

Answer 7

1. Noradrenaline infusion 0.1mcg/kg/min
2. Metaraminol infusion 10mg/50mL saline - start at 5mL/hr
3. Vasopressin 2U/hr
4. Glucagon 1-5mg over 5mins (b-blocker reversal)

Question 8

What further adjuncts can be considered once the patient is stable?

Answer 8

1. Steroids to prevent late response - Hydrocortisone 2-4mg/kg or Dexamethasone 0.2-0.4mg/kg
2. 2nd Generation anti-histamine (Loratadine)

Question 9

What is the ANZCA DRSABCD of anaphylaxis?

Answer 9

1. Danger and diagnosis - hypotensive with bronchospasm - cease all triggers
2. Send for help
3. Airway - establish an airway if airway oedema or compromise
4. Breathing - FiO2 1.0
5. Circulation - CPR if no pulse, give 1mg Adrenaline and follow CPR protocol, IV fluid bolus 20mLs/kg and rpt as required
6. Drugs - Adrenaline - bolus, rpt, infusion