What is the recommended intravenous (IV) adrenaline dilution and administration protocol for an adult patient experiencing anaphylaxis?

IV Adrenaline Dilution in Anaphylaxis

For adult anaphylaxis requiring IV adrenaline, use a dilution of 1:10,000 (0.1 mg/mL) at a dose of 0.05 to 0.1 mg (50-100 mcg) per bolus, or prepare an infusion by adding 1 mg of 1:1000 adrenaline to 250 mL D5W (yielding 4 mcg/mL) and infuse at 0.05-0.1 mcg/kg/min (1-4 mcg/min in adults, titrating up to maximum 10 mcg/min). 1, 2

Critical Context: When to Use IV Adrenaline

Intramuscular (IM) adrenaline remains the first-line route for anaphylaxis treatment. 1 IV adrenaline should only be considered in specific circumstances:

• When an IV line is already in place and the patient has anaphylactic shock unresponsive to IM doses 1
• After failure of multiple IM injections (typically ≥3 doses) 2, 3
• In cardiac arrest from anaphylaxis 1
• In monitored settings such as operating rooms, intensive care units, or emergency departments where continuous hemodynamic monitoring is available 1, 2

IV Bolus Dosing Protocol

Dilution and Preparation

• Use 1:10,000 concentration (0.1 mg/mL) for IV bolus administration 1
• This is 10% of the cardiac arrest dose and critical to avoid overdose 1

Dose by Severity

• Grade II reactions (moderate): 20 mcg IV bolus 2
• Grade III reactions (severe): 50-100 mcg IV bolus 1, 2
• Grade IV reactions (cardiac arrest): 1 mg IV following advanced life support guidelines 2

Administration Technique

• Titrate slowly to response rather than giving rapid bolus 1, 2
• Repeat every 5-15 minutes as needed if symptoms persist 1
• Monitor continuously for cardiac adverse effects including arrhythmias and hypertension 1

IV Infusion Protocol (For Refractory Cases)

Preparation Method

Add 1 mg (1 mL) of 1:1000 adrenaline to 250 mL of D5W to yield a concentration of 4.0 mcg/mL. 2, 3

Infusion Rates

• Starting rate: 0.05-0.1 mcg/kg/min (or 1-4 mcg/min in adults) 2, 3
• Titrate upward based on clinical response and hemodynamic parameters 2, 3
• Maximum rate: 10 mcg/min 2, 3

When to Initiate Infusion

• After ≥3 IM adrenaline boluses without adequate response 2
• As an alternative to repeated IV boluses in patients not in cardiac arrest 1
• For post-arrest shock in patients with anaphylaxis 1

Critical Safety Considerations

Common Pitfalls to Avoid

Never confuse concentrations: The most dangerous error is using 1:1000 (1 mg/mL) concentration IV instead of 1:10,000 (0.1 mg/mL), which results in a 10-fold overdose. 2, 3

Do not delay IM adrenaline while establishing IV access: IM injection in the anterolateral thigh achieves peak plasma concentrations in 8±2 minutes compared to 34±14 minutes with subcutaneous administration, and should never be delayed for IV access. 1, 3

Avoid IV bolus in non-critical settings: IV adrenaline carries significant risk of dilution/dosing errors and serious cardiac adverse effects; the IM route is safer for first-line treatment. 3

Monitoring Requirements

• Continuous cardiac monitoring is mandatory during IV adrenaline administration 1
• Frequent blood pressure monitoring to assess response and detect hypertension 1
• Observe for arrhythmias, particularly in elderly patients or those with cardiac disease 1

Adjunctive Measures During IV Adrenaline Use

Fluid Resuscitation

• Grade II reactions: 0.5 L crystalloid bolus initially 2
• Grade III reactions: 1 L crystalloid bolus initially 2
• Repeat boluses up to 20-30 mL/kg based on clinical response 2
• Aggressive fluid resuscitation is imperative to combat vasodilation and capillary leak 2

Alternative Vasopressors

If hypotension persists despite adrenaline infusion, consider alternative vasopressors such as norepinephrine, vasopressin, phenylephrine, or metaraminol. 2

Special Populations

Patients on beta-blockers may require glucagon IV 1-2 mg due to potential resistance to adrenaline's effects. 2

Post-Treatment Observation

• Minimum 6 hours observation in a monitored area until stable and symptoms have resolved 2
• Grade III-IV reactions typically require ICU admission 2
• Extended observation may be needed for patients requiring >1 dose of adrenaline due to risk of biphasic reactions 1, 2

Evidence Quality Note

The 2020 American Heart Association guidelines provide the most authoritative and recent recommendations, rating IV adrenaline as Class 2a (reasonable to consider) with Level C-LD evidence (limited data from observational studies and case reports). 1 There are no randomized controlled trials evaluating IV versus IM adrenaline in anaphylaxis, and evidence is extrapolated from nonfatal cases and pathophysiology. 1