What are the indications and dosing guidelines for adrenaline (epinephrine) infusion?

Adrenaline (Epinephrine) Infusion: Indications and Dosing

Adrenaline infusion is indicated when multiple bolus doses fail to control severe hypotension or bronchospasm in refractory anaphylaxis (typically after 2-3 failed intramuscular or intravenous bolus attempts), or for hypotension associated with septic shock requiring sustained vasopressor support. 1

Primary Indications

Refractory Anaphylaxis

• Start an adrenaline infusion when several bolus doses are required for severe hypotension or bronchospasm, as adrenaline has a short half-life requiring sustained delivery 1
• This typically occurs after 2-3 failed intramuscular or intravenous bolus attempts 1
• The infusion provides sustained alpha-agonist activity (vasoconstriction), beta-agonist effects (bronchodilation, cardiac stimulation), and reduces further mediator release 1

Septic Shock

• Adrenaline is indicated to increase mean arterial blood pressure in adult patients with hypotension associated with septic shock 2
• Consider as a second-line agent when norepinephrine alone does not achieve target MAP 1

Preparation and Concentration

Standard adult concentration: Add 1 mg of 1:1000 adrenaline to 250 mL of D5W to yield a concentration of 4.0 mcg/mL 1

This preparation allows for precise titration using standard infusion equipment 1

Dosing Protocols

Adult Dosing for Anaphylaxis

• Initial rate: 1-4 mcg/min, titrated up to a maximum of 10 mcg/min based on clinical response 1
• Alternative protocol: Start at 5-15 mcg/min using the 1:100,000 solution, titrating up or down depending on response or toxicity 1

Septic Shock Dosing

• FDA-approved range: 0.05 mcg/kg/min to 2 mcg/kg/min, titrated to achieve desired mean arterial pressure 2
• Wean gradually when discontinuing 2

Administration Requirements

Route and Access

• Infuse epinephrine into a large vein 2
• Central venous access is preferred to minimize extravasation risk 1

Volume Resuscitation

• Administer saline 0.9% or lactated Ringer's solution at a high rate via a large-bore IV cannula, with large volumes potentially required 1
• Ensure adequate volume resuscitation before and during adrenaline administration, particularly for septic shock 1

Monitoring

• Monitor vital signs continuously during infusion and for an extended period after discontinuation 1
• Monitor for acute severe hypertension 2
• Observe for cardiac arrhythmias and myocardial ischemia, particularly in patients with underlying heart disease 2

Adjunctive Medications for Anaphylaxis

Secondary management options include:

• Chlorphenamine 10 mg IV and hydrocortisone 200 mg IV 1
• Combined H1 and H2 antagonists: diphenhydramine 25-50 mg IV plus ranitidine 50 mg IV for superior results 1

Critical Safety Considerations

Cardiac Complications

• Potential for serious cardiac arrhythmias, including fatal ventricular fibrillation 2
• May induce myocardial ischemia, particularly in patients with underlying heart disease 2, 3
• Risk of rapid rises in blood pressure producing cerebral hemorrhage 2

Extravasation Management

• Avoid extravasation into tissues, which causes local necrosis 2
• If extravasation occurs: Infiltrate phentolamine 5-10 mg diluted in 10-15 mL saline at the site immediately 1

Pulmonary Complications

• Potential for pulmonary edema, which may be fatal 2

Renal Effects

• Potential for oliguria or renal impairment 2

Common Pitfalls to Avoid

Dosing Confusion

• Critical distinction: Anaphylaxis requires LOW-DOSE intramuscular boluses (0.3-0.5 mg IM) initially, NOT high-dose intravenous push 3, 4, 5
• Confusion between anaphylaxis dosing and cardiac arrest dosing has led to iatrogenic overdoses causing severe systolic dysfunction and potentially lethal cardiac complications 3
• Intravenous bolus doses of adrenaline should be avoided unless cardiac arrest occurs 4

Inadequate Volume Resuscitation

• Never start adrenaline infusion without ensuring adequate fluid resuscitation first, as vasoconstriction in hypovolemic patients causes severe organ hypoperfusion 1

Premature Discontinuation

• Protracted or biphasic reactions can occur; patients should be observed in the emergency department setting for at least 6 hours after an acute event 4

Post-Infusion Management

• Arrange transfer to an appropriate Critical Care area after anaphylaxis 1
• Take Mast Cell Tryptase samples at specified times for diagnostic confirmation 1
• Provide follow-up with accurate identification of likely cause(s), immunotherapy if available, and an action plan with adrenaline auto-injector where further accidental exposures are likely 4