What is the management of acute angioedema post anesthesia?

Management of Acute Angioedema Post-Anesthesia

Immediately secure the airway with 100% oxygen, remove all potential causative agents, administer intravenous adrenaline 50 mcg (0.5 mL of 1:10,000) as first-line treatment, and prepare for emergency intubation or surgical airway if airway compromise develops. 1

Immediate Airway Assessment and Stabilization

The airway is the absolute priority - angioedema can rapidly progress to complete airway obstruction within minutes. 1, 2

• Assess for signs of impending airway closure: change in voice, loss of ability to swallow, stridor, difficulty breathing, or arterial oxygen desaturation 1, 2
• Administer 100% oxygen immediately via facemask or bag-valve-mask while maintaining airway patency 1
• Position the patient head-up to reduce venous congestion and edema progression 1
• Call for help immediately - notify senior anesthesiologist and surgical team; activate peri-arrest protocols if signs of airway compromise are present 1
• Prepare for emergency intubation with videolaryngoscopy available for first attempt, limiting intubation attempts to avoid worsening edema 1
• Have surgical airway equipment immediately available at bedside, as airway anatomy may be severely distorted by angioedema 1, 2

Immediate Pharmacologic Management

First-Line Treatment: Adrenaline (Epinephrine)

Administer adrenaline intravenously as early as possible - this is consensus-based immediate management regardless of angioedema subtype. 1

• Initial dose: 50 mcg IV (0.5 mL of 1:10,000 solution) for adults 1
• Repeat doses every 3-5 minutes if severe hypotension, bronchospasm, or progressive angioedema persists 1
• Consider adrenaline infusion if multiple bolus doses are required, given its short half-life 1
• Alternative routes if no IV access: subcutaneous 0.3 mL (0.1%), intramuscular, intralingual, or intraosseous 2, 3

Remove All Potential Triggers

• Immediately discontinue all IV colloids, antibiotics, and any recently administered medications 1
• Remove latex exposure if present 1
• Maintain anesthesia with inhalational agent only if surgery is ongoing 1

Secondary Pharmacologic Management

Standard Adjunctive Therapy (Histamine-Mediated Component)

Administer these medications while continuing airway management and adrenaline as needed:

• Chlorphenamine (diphenhydramine) 50 mg IV 1, 2
• Hydrocortisone 200 mg IV (or methylprednisolone 125 mg IV) 1, 2
• Add H2-blocker: ranitidine 50 mg IV or famotidine 20 mg IV 2, 3

Bradykinin-Mediated Angioedema Treatment

If angioedema is suspected to be bradykinin-mediated (ACE inhibitor use, hereditary angioedema, or poor response to standard therapy):

• Icatibant 30 mg subcutaneously in the abdominal area - may repeat at 6-hour intervals (maximum 3 doses in 24 hours) 2, 3, 4
• Tranexamic acid 1000 mg IV infused over 10 minutes 2
• Fresh frozen plasma 10-15 mL/kg if specific targeted therapies unavailable 3
• C1 esterase inhibitor 1000-2000 units IV if hereditary angioedema is known or suspected 3

Critical caveat: Standard allergy treatments (antihistamines, corticosteroids, epinephrine) are NOT effective for pure bradykinin-mediated angioedema, but should still be given initially when the etiology is uncertain. 3, 5

Fluid Resuscitation

• Administer normal saline 0.9% or lactated Ringer's solution at high rate via large-bore IV cannula 1
• Large volumes may be required if hypotension is present 1

Management of Associated Cardiovascular Instability

If Hypotension Persists Despite Adrenaline

• Consider alternative vasopressor: metaraminol or noradrenaline infusion according to clinician experience 1
• Elevate patient's legs if hypotensive 1

If Bradycardia Develops (Occurs in ~10% of Anaphylaxis Cases)

• Atropine 0.5-1 mg IV may be required to treat bradycardia 1, 2
• Note: Bradycardia occurs in approximately 10% of allergic anaphylaxis during anesthesia and does not exclude the diagnosis 1

Persistent Bronchospasm Management

• Salbutamol IV infusion for persistent bronchospasm 1
• Metered-dose inhaler via breathing-system connector if appropriate equipment available 1

Monitoring and Observation

• Continuous monitoring of vital signs, oxygen saturation, and airway patency 2
• Observe for delayed progression - symptoms can develop up to 1 hour after exposure, though typically occur within minutes 1
• Extended observation period required - do not discharge until completely stable, as recurrence can occur 3
• Monitor for post-obstructive pulmonary edema if significant airway obstruction occurred 1

Critical Pitfalls to Avoid

• Do not delay adrenaline administration while attempting to determine angioedema subtype - give it immediately 1, 2
• Do not assume absence of cutaneous signs excludes anaphylaxis - hypotension may be the sole feature in 10% of cases 1
• Do not perform unnecessary airway manipulation (e.g., direct laryngoscopy for examination) as trauma can worsen angioedema 2, 3
• Do not discharge patients with oropharyngeal or laryngeal involvement without adequate observation period 3
• Do not rely solely on antihistamines and steroids if bradykinin-mediated angioedema is suspected 3, 5

Special Considerations

• Timing of onset: Anaphylaxis typically occurs within minutes but may be delayed up to 1 hour; latex, antibiotics, and IV colloids can cause delayed reactions 1
• Risk factors for severe reactions: Pre-existing asthma increases risk of bronchospasm 1
• Cardiac arrest: Occurs in approximately 6% of allergic anaphylaxis cases during anesthesia 1
• Post-event workup: Obtain mast cell tryptase levels and arrange follow-up allergy testing once patient stabilized 6