What is the appropriate dose of adrenaline (epinephrine) for a 60kg male patient with septic shock, given a 100ml Normal Saline (NS) solution containing 4 micrograms per milliliter (mcg/mL) of adrenaline?

Adrenaline Infusion Calculation for 60kg Patient with Septic Shock

For a 60kg patient with 4 ampoules of adrenaline (4mg total) in 100ml NS, the concentration is 40 mcg/ml, and the infusion rate should start at 0.1-1.0 mcg/kg/min (6-60 mcg/min or 0.15-1.5 ml/hr), titrated to achieve MAP ≥65 mmHg.

Critical Context: Adrenaline is NOT First-Line for Septic Shock

Norepinephrine must be used as the first-line vasopressor in septic shock, not adrenaline. 1, 2 Adrenaline appears equally efficacious to norepinephrine but is not routinely used due to its metabolic side effects, including transient lactic acidosis through β2-adrenergic stimulation of skeletal muscle. 1

When Adrenaline Should Be Used

Add adrenaline only as a second or third-line agent when norepinephrine plus vasopressin fail to achieve target MAP ≥65 mmHg. 2 The recommended escalation sequence is:

1. First-line: Norepinephrine targeting MAP ≥65 mmHg 1, 2
2. Second-line: Add vasopressin 0.03 units/min to norepinephrine 1, 2
3. Third-line: Add adrenaline 0.05-2 mcg/kg/min if refractory hypotension persists 2

Adrenaline Dosing Calculation for Your Preparation

Concentration Calculation

• 4 ampoules of adrenaline = 4mg total (assuming standard 1mg/ml ampoules) 1
• Diluted in 100ml NS = 4000 mcg ÷ 100ml = 40 mcg/ml concentration

Dosing for 60kg Patient

Starting dose: 0.1 mcg/kg/min 1

• 0.1 mcg/kg/min × 60kg = 6 mcg/min
• 6 mcg/min ÷ 40 mcg/ml = 0.15 ml/hr (starting rate)

Typical therapeutic range: 0.1-1.0 mcg/kg/min 1, 2

• Low dose: 6 mcg/min = 0.15 ml/hr
• High dose: 60 mcg/min = 1.5 ml/hr

Maximum dose: Up to 5 mcg/kg/min may be necessary in refractory shock 1

• 5 mcg/kg/min × 60kg = 300 mcg/min
• 300 mcg/min ÷ 40 mcg/ml = 7.5 ml/hr (maximum rate)

Practical Titration Protocol

Start at the lowest dose (0.1 mcg/kg/min = 0.15 ml/hr) and titrate upward in increments of 0.03 mcg/kg/min every 10-15 minutes until MAP ≥65 mmHg is achieved. 2 For this 60kg patient:

• Initial: 0.15 ml/hr (6 mcg/min)
• Titration increments: Add 0.045 ml/hr (1.8 mcg/min) every 10-15 minutes
• Target: MAP ≥65 mmHg with adequate tissue perfusion 2

Critical Monitoring Requirements

Continuous arterial blood pressure monitoring via arterial catheter is mandatory for all patients requiring vasopressors. 2, 3 Monitor beyond MAP alone:

• Tissue perfusion markers: Lactate clearance, urine output ≥0.5 ml/kg/hr, mental status, capillary refill 2, 3
• Cardiac monitoring: Heart rate and rhythm (adrenaline increases risk of tachyarrhythmias) 1, 2
• Metabolic effects: Serial lactate levels (adrenaline causes transient lactic acidosis) 2

Critical Safety Warnings

Adrenaline increases myocardial oxygen consumption more than norepinephrine and carries significantly higher risk of ventricular arrhythmias (RR 0.35; 95% CI 0.19-0.66 when comparing norepinephrine to dopamine). 2

Extravasation can cause severe skin injury and tissue necrosis. 1 Administer through central venous access whenever possible. 2 If extravasation occurs, inject phentolamine 0.1-0.2 mg/kg (up to 10mg) diluted in 10ml of 0.9% sodium chloride intradermally at the site. 1

Common Pitfalls to Avoid

• Never use adrenaline as first-line monotherapy in septic shock - this violates all major guidelines 1, 2
• Do not rely on lactate clearance as the sole resuscitation endpoint when using adrenaline, as it interferes with lactate metabolism 2
• Avoid combining with other sympathomimetic agents without careful monitoring, as additive effects increase arrhythmia risk 2
• Do not exceed 0.3 mcg/kg/min (18 mcg/min for 60kg patient) without considering alternative therapies like dobutamine for cardiac dysfunction 2