Suspect Anaphylaxis
Unexpected cardiovascular or respiratory compromise during/after drug administration
All Pathways
AnesthesiologyEmergency
Perioperative Anaphylaxis Management (NAP6/RCUK 2021)
Perioperative Anaphylaxis Management (NAP6/RCUK 2021): Suspect Anaphylaxis → Recognition - Think ANAPHYLAXIS → STOP Likely Trigger Agent → Call for Help...
Pathway Overview
14 steps
Algorithm Steps
14 total
01Start 02Action Recognition - Think ANAPHYLAXIS
Consider anaphylaxis with any unexpected compromise
- Cardiovascular: hypotension, tachycardia, cardiac arrest
- Respiratory: bronchospasm, increased airway pressure, hypoxia
- Skin: flushing, urticaria, angioedema (may be hidden by drapes)
- Note: Skin signs may be absent in 10-20% of perioperative cases
- Common triggers: NMBAs, antibiotics, chlorhexidine, latex, colloids
03Action STOP Likely Trigger Agent
Immediately cease administration of suspected cause
- Stop antibiotic infusion
- Stop colloid
- Remove latex from field
- Stop blood transfusion if running
- Document timing of all drugs given
04Action Call for Help
Summon assistance immediately
- Declare anaphylaxis emergency
- Call for extra personnel
- Get anaphylaxis kit/epinephrine
- Note time of reaction
05Decision Severity Assessment
Cardiovascular compromise present?
- Cardiac arrest → CPR
- Severe hypotension (SBP <50 in anesthetized patient)
- Severe bronchospasm
- Mild: urticaria, minor hypotension responsive to fluids
06Action Epinephrine (Adrenaline)
FIRST-LINE TREATMENT - Do not delay
- IV ACCESS PRESENT:
- Adult: 50 mcg IV (0.5 mL of 1:10,000) titrated
- Repeat every 1-2 min as needed
- Infusion: 0.05-0.5 mcg/kg/min if refractory
- NO IV ACCESS:
- Adult: 500 mcg IM (0.5 mL of 1:1,000)
- Anterolateral thigh
- Repeat every 5 min if needed
07Decision Cardiac Arrest?
SBP <50 mmHg in anesthetized = start CPR
08Warning ⚠️ CPR - Anaphylactic Arrest
High-dose epinephrine, prolonged resuscitation
- Standard CPR algorithm
- Epinephrine 1 mg IV every 3-5 min
- Large volume fluid resuscitation
- Prolonged resuscitation may be successful
- Consider ECMO if available
09Action Second-Line Treatments
After epinephrine and fluids
- Hydrocortisone 200 mg IV (prevents late phase)
- Chlorphenamine 10 mg IV (histamine blocker)
- Vasopressin 2 U IV bolus if refractory to epinephrine
- Glucagon 1-2 mg IV if on beta-blockers
- Bronchospasm: salbutamol nebulizer, IV magnesium 2g
10Action Mast Cell Tryptase Samples
CRITICAL for diagnosis confirmation
- Sample 1: As soon as patient stable (don't delay resuscitation)
- Sample 2: 1-2 hours after onset
- Sample 3: >24 hours (baseline)
- Send all 3 samples
- Document all drugs and timings
11Action Post-Event Management
Monitoring and referral
- ICU/HDU admission for severe reactions
- Observe 6-12 hours minimum (biphasic reactions)
- Refer to allergy clinic
- Document fully in notes
- Prescribe epinephrine auto-injector if appropriate
12Outcome Patient Stabilized
Document, refer for allergy testing
- Path rejoins step 09Shared downstream outcome
13Action IV Fluid Resuscitation
Crystalloid bolus for hypotension
- Crystalloid (Hartmann's or 0.9% saline)
- Adult: 500-1000 mL bolus (20 mL/kg)
- Repeat as needed - may require 2-4 L
- Avoid colloids (may be trigger)
- Elevate legs if hypotensive
- Path rejoins step 07Shared downstream outcome
14Action Airway & Breathing
100% oxygen, secure airway if not already
- 100% FiO2
- Intubate if not already (early - angioedema may progress)
- Bronchospasm: inhaled salbutamol, IV salbutamol if severe
- May need high airway pressures
- Path rejoins step 07Shared downstream outcome
Guideline Source
Emergency treatment of anaphylaxis - Resuscitation Council UK/NAP6
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Anesthetized patients may not show typical skin signs
- Bronchospasm may be sole presenting sign under drapes
- Hypotension under anesthesia may be profound
- Does not cover allergy testing/referral details
Applicable Regions
USEUUKglobal
UK: Based on RCUK/NAP6 recommendations
US: Compatible with ACAAI guidelines
Version 1Next review: 2027-01-01
Next steps
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Related Resources
Frequently Asked Questions
What is the Perioperative Anaphylaxis Management (NAP6/RCUK 2021)?
The Perioperative Anaphylaxis Management (NAP6/RCUK 2021) is a emergency clinical algorithm for Anesthesiology. It provides a structured decision tree to guide clinical decision-making, based on Emergency treatment of anaphylaxis - Resuscitation Council UK/NAP6.
What guideline is the Perioperative Anaphylaxis Management (NAP6/RCUK 2021) based on?
This algorithm is based on Emergency treatment of anaphylaxis - Resuscitation Council UK/NAP6 (DOI: 10.1016/j.bja.2018.04.015).
What are the limitations of the Perioperative Anaphylaxis Management (NAP6/RCUK 2021)?
Known limitations include: Anesthetized patients may not show typical skin signs; Bronchospasm may be sole presenting sign under drapes; Hypotension under anesthesia may be profound; Does not cover allergy testing/referral details. Individual patient factors may require deviation from these recommendations.
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