What is the recommended epinephrine (adrenaline) dose for hypotension given as a bolus according to Canadian guidelines?

Epinephrine Dosing for Hypotension According to Canadian Guidelines

For perioperative hypotension in adults, the recommended epinephrine bolus dose is 20-50 mcg IV for moderate hypotension (Grade II), escalating to 50-100 mcg for severe hypotension (Grade III), and 1 mg for cardiac arrest (Grade IV), based on international consensus guidelines that inform Canadian practice. 1

Severity-Based Dosing Algorithm

The British Journal of Anaesthesia provides a graded approach that is widely adopted in Canadian perioperative settings 1:

Grade II Hypotension (Moderate)

• Initial bolus: 20 mcg IV 1
• If inadequate response at 2 minutes, escalate to 50 mcg 1
• Repeat every 2 minutes as needed 1
• Concurrent crystalloid: 500 mL rapid bolus 1

Grade III Hypotension (Severe)

• Initial bolus: 50 mcg IV 1
• Alternative: 100 mcg bolus if inadequate response to other vasopressors or bronchodilators 1
• If inadequate response at 2 minutes, escalate to 200 mcg 1
• Concurrent crystalloid: 1 L rapid bolus, repeat as needed up to 30 mL/kg 1

Grade IV (Cardiac Arrest)

• 1 mg bolus 1
• Repeat as per Advanced Life Support guidelines 1

Refractory Hypotension Management

When hypotension persists >10 minutes after symptom onset 1:

• Double the epinephrine bolus dose 1
• After more than three boluses, add epinephrine infusion 0.05-0.1 mcg/kg/min 1
• Consider adding vasopressin 1-2 IU bolus with or without infusion (2 IU/h) 1
• Consider norepinephrine infusion 0.05-0.5 mcg/kg/min 1

Alternative Infusion Protocol

For sustained hypotension requiring continuous support 2:

• Prepare 1:100,000 epinephrine solution 2
• Initial infusion rate: 30-100 mL/h (5-15 mcg/min) 2
• This approach is safer than repeated boluses for refractory cases 3

Critical Safety Considerations

Fluid Resuscitation Priority

• Always administer crystalloid boluses concurrently with epinephrine 1, 2
• Minimum 30 mL/kg crystalloid should be given before or with epinephrine 2

Monitoring Requirements

• Continuous hemodynamic monitoring is mandatory during epinephrine administration 3, 2
• Fatal overdose and cardiac complications have been reported with IV epinephrine 3

Administration Precautions

• Never mix epinephrine with sodium bicarbonate or alkaline solutions in the IV line, as epinephrine is inactivated 2
• Use small incremental doses (20-100 mcg) rather than cardiac arrest doses to minimize vasospasm risk 3

Context-Specific Dosing

Anaphylaxis-Related Hypotension

The graded approach above is specifically designed for perioperative anaphylaxis 1, which is a common cause of acute hypotension requiring epinephrine boluses.

Cardiogenic Shock

In heart failure with persistent hypotension, epinephrine should be restricted to patients failing other vasoactive agents 1, with infusion dosing of 0.05-0.5 mcg/kg/min 1.

Important Caveats

Epinephrine remains the drug of choice for anaphylaxis with critical compromise and should never be withheld due to concern for cardiac complications 3. However, the risk of coronary vasospasm exists, particularly with larger boluses. For severe vasospasm, intracoronary nitroglycerin 200 mcg can reverse diffuse coronary spasm immediately 3.

Research data suggest that while bolus epinephrine effectively increases blood pressure in hypotensive patients 4, observational studies have raised concerns about mortality associations in certain populations 5, though this may reflect confounding by indication rather than causation.