ANAPHYLAXIS

Recognition

Definition

• “Anaphylaxis is a severe, life-threatening, generalised or systemic hypersensitivity reaction.” (RESUS.org).

Risk Factors

• Asthma
• Atopy
• Exposure to common sensitizer
• Previous anaphylaxis

Common Causes

• Insect stings
• Latex
• Food
  • Nuts
  • Milk
  • Egg
  • Fish
  • Shellfish
• Penicillin
• Angiotensin Converting Enzyme inhibitors (ACEi)

History

• If possible, ascertain if patient has:
  • Previous admissions with anaphylaxis
  • Any known allergies
  • Any admissions to Intensive Care Unit (ITU) with anaphylaxis
  • Any allergies

General symptoms

• Shortness of breath (dyspnoea)
• Cyanosis
• Angio-oedema
• Rhinitis
• Clammy
• Abdominal pain
• Dizziness
• Collapse
• Urticaria
• Diarrhoea

General Signs

• Low oxygen saturations
• Tachypnoea
• Wheeze
• Stridor
• Pale
• Cool peripheries
• Delayed capillary refill time
• Reduced skin turgor
• Dry mucous membranes
• Hypotensive
• Tachycardic
• Decreased urine output

Initial Assessment and Investigations

• ABCDE assessment
• Assess patient’s airway – call an anaesthetist if airway compromised
• Assess patients face for swelling
• Monitor oxygen saturations and respiratory rate
• Give 15 L/min via a reservoir mask
• Call for senior help
• Once anaphylaxis recognised give immediate management and remove the antigen if identified
• Arterial blood gas (ABG) but this is not a priority
• Examine patient’s chest
  • Listening for:
    • Wheeze
• Obtain intravenous access by placing 2 large bore cannulae in the antecubital fossa. Take blood to check Full Blood Count (FBC), Urea and Electrolytes (U&Es), Liver Function Tests (LFTs), Mast Cell Tryptase, Calcium and Glucose
• Check Capillary Refill Time (CRT) - hold for five seconds and refilling should occur in 3 seconds
• Assess pulse rate, rhythm and character
  • If no pulse present start advanced life support
• Monitor heart rate and blood pressure
• Raise the legs to help restore circulation
• Listen to patient’s heart sounds
• Intravenous (IV) fluid bolus of 0.9% sodium chloride 250-500 ml over 10-15 mins as described in management.
• See more details in the “Circulation” Chapter in the “Response” Section under “Fluid Challenge.”
•  Repeat as required to maintain blood pressure
• 12 lead Electrocardiogram (ECG)
• Consider cardiac monitoring
• Remove the antigen if identified and not done already
• Check pupils are equal and reactive
• Assess Glasgow Coma Scale or ACVPU using the NEWS2 chart
• Check patient’s temperature and blood sugar
• Examine patient’s abdomen and legs for rash
• Consider venous thromboembolism prophylaxis

Response

Management

 

Immediate management

• Follow RESUS guidelines

Anaphylaxis algorithm

Referrals

• Discuss with senior member of the team
• Contact critical care outreach team
• Consider referral to Intensive Care Unit (ICU) if:
  • Failure to respond to medical management
  • Patient requires ventilator support
  • Patient requires blood pressure support
  • Deterioration of blood gas following medical management

Future management

• A second sample of mast cell tryptase should be taken 1 - 2 hours post event
• Patient should be observed for 6 -12 hours post event in case of biphasic reaction
• Patient should be referred to specialist allergy service