What is the recommended initial dose of adrenaline (epinephrine) infusion for a patient, considering factors such as age, weight, and underlying medical conditions?

Adrenaline Infusion Dosing

For adults requiring adrenaline infusion after failed bolus doses, start at 1-4 mcg/min (0.05-0.1 mcg/kg/min) and titrate up to a maximum of 10 mcg/min based on clinical response, using a 4 mcg/mL concentration prepared by adding 1 mg of 1:1000 epinephrine to 250 mL D5W. 1

Adult Dosing Algorithm

Preparation and Initial Rate

• Standard concentration: Add 1 mg (1 mL) of 1:1000 epinephrine to 250 mL D5W to yield 4 mcg/mL 1
• Alternative concentration (if infusion pump available): 1 mg (1 mL) in 100 mL saline = 10 mcg/mL (1:100,000 solution) 1
• Starting rate: 1-4 mcg/min (15-60 drops/min with microdrop apparatus where 60 drops = 1 mL = 60 mL/h) 1
• With infusion pump: 30-100 mL/h of the 1:100,000 solution (delivers 5-15 mcg/min) 1
• Maximum rate: Titrate up to 10 mcg/min 1

Critical Indications for Infusion

Adrenaline infusion should be considered when: 1

• Several bolus doses of adrenaline (50 mcg IV each) are required for severe hypotension or bronchospasm
• Anaphylaxis is refractory to initial bolus therapy
• Profound hypotension persists despite volume replacement and multiple injected doses

Pediatric Dosing Algorithm

Standard Infusion Dosing

• Starting rate: 0.1 mcg/kg/min for continued shock after volume resuscitation 1, 2
• Therapeutic range: 0.1-1.0 mcg/kg/min for most patients 1, 2
• Maximum dose: Up to 5 mcg/kg/min in exceptional circumstances 1, 2

Preparation Methods

• Standard method: Prepare 1 mL of 1:10,000 adrenaline for each 10 kg body weight (0.1 mL/kg of 1:10,000 = 10 mcg/kg) 1
• "Rule of 6" method: 0.6 × body weight (kg) = mg of adrenaline diluted to 100 mL saline; then 1 mL/h delivers 0.1 mcg/kg/min 1
• Pediatric dosing: 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution; maximum 0.3 mg) 1

Context-Specific Considerations

When Infusion is Mandatory

The guidelines emphasize that adrenaline infusion should be started when multiple bolus doses are needed because adrenaline has a short half-life (< 5 minutes) 1, 3. The pharmacokinetic steady state is achieved within 10-15 minutes of continuous infusion 3.

Monitoring Requirements

Continuous hemodynamic monitoring is essential when administering IV adrenaline infusions 1. However, if monitoring equipment is unavailable but the clinician deems infusion essential after failure of several bolus injections, monitor by available means including every-minute blood pressure, pulse measurements, and ECG monitoring if available 1.

Critical Safety Warnings

Potentially lethal arrhythmias: IV adrenaline should only be used during cardiac arrest or for profoundly hypotensive patients who have failed to respond to IV volume replacement and several injected doses 1

Extravasation injury: IV infiltration can result in severe skin injury 1, 2. If extravasation occurs, inject phentolamine 0.1-0.2 mg/kg (up to 10 mg) diluted in 10 mL of 0.9% sodium chloride intradermally at the site to counteract dermal vasoconstriction 1, 2

Concentration errors: Extreme caution is required to ensure selection of the appropriate concentration (1:1000 vs 1:10,000) for the route of administration 1, 2

Special Populations

Beta-Blocker Therapy

When beta-blocker therapy complicates treatment, consider glucagon 1-5 mg IV over 5 minutes (20-30 mcg/kg in children, maximum 1 mg) followed by infusion at 5-15 mcg/min 1

Elderly Patients

Plasma metabolic clearance of epinephrine is higher in elderly men (144.8 vs 78 mL/kg/min), suggesting potentially faster drug elimination 3

Body Weight Effects

Higher body weight is associated with higher plasma epinephrine clearance and lower concentration plateau, which may require dose adjustment 3

Common Pitfalls to Avoid

• Never use adrenaline infusion as first-line therapy: Always attempt bolus dosing first (50 mcg IV for adults, 1 mcg/kg for children) 1
• Do not delay volume resuscitation: Large volumes of crystalloid (1-2 L for adults at 5-10 mL/kg in first 5 minutes; up to 30 mL/kg in first hour for children) must be given concurrently 1
• Avoid high-dose epinephrine in cardiac arrest: High-dose IV epinephrine (0.1 mg/kg) is no longer recommended for routine resuscitation 1
• Do not use intratracheal route: Intratracheal doses up to 10 mcg/kg (one-third of recommended resuscitation dose) have no effect on arterial pressure or heart rate, whereas 0.1 mcg/kg IV produces significant hemodynamic effects 4