Perioperative Anaphylaxis Management (NAP6/RCUK 2021)

Algorithm Steps

1. ▶

   Start

   Suspect Anaphylaxis

   Unexpected cardiovascular or respiratory compromise during/after drug administration

   1. ●

      Action

      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
      1. ●

         Action

         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
         1. ●

            Action

            Call for Help

            Summon assistance immediately

            • Declare anaphylaxis emergency
            • Call for extra personnel
            • Get anaphylaxis kit/epinephrine
            • Note time of reaction
            1. ◆

               Decision

               Severity Assessment

               Cardiovascular compromise present?

               • Cardiac arrest → CPR
               • Severe hypotension (SBP <50 in anesthetized patient)
               • Severe bronchospasm
               • Mild: urticaria, minor hypotension responsive to fluids
               1. ●

                  Action

                  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
                  1. ◆

                     Decision

                     Cardiac Arrest?

                     SBP <50 mmHg in anesthetized = start CPR

                     1. ⚠

                        Warning

                        ⚠️ 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
                        1. ●

                           Action

                           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
                           1. ●

                              Action

                              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
                              1. ●

                                 Action

                                 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
                                 1. ✓

                                    Outcome

                                    Patient Stabilized

                                    Document, refer for allergy testing

               2. ●

                  Action

                  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
               3. ●

                  Action

                  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