How do I start the infusion pump for a 60kg person with norepinephrine (4mg in 50ml Normal Saline (NS)) at a rate of 0.05mcg/kg/min?

Norepinephrine Infusion Pump Setup

For a 60kg patient requiring 0.05mcg/kg/min with your concentration of 4mg norepinephrine in 50mL NS (80mcg/mL), set your infusion pump to 2.25 mL/hour.

Calculation Breakdown

Your specific setup requires the following calculation:

• Desired dose: 0.05 mcg/kg/min × 60 kg = 3 mcg/min 1
• Your concentration: 4mg in 50mL = 4000mcg in 50mL = 80 mcg/mL 2
• Required rate: (3 mcg/min ÷ 80 mcg/mL) × 60 min/hour = 2.25 mL/hour 2

Critical Safety Considerations Before Starting

Address hypovolemia FIRST with crystalloid boluses (minimum 30 mL/kg) before or concurrent with norepinephrine administration, as vasoconstriction in hypovolemic patients causes severe organ hypoperfusion despite "normal" blood pressure 1, 3.

Administration Route

• Central venous access is strongly preferred to minimize extravasation risk and tissue necrosis 1, 3, 2
• If central access is unavailable, peripheral IV can be used temporarily with strict monitoring, but transition to central access as soon as practical 1

Concentration Concerns

• Your concentration (80 mcg/mL) is significantly more concentrated than standard recommendations 1, 2
• The FDA recommends 4mg in 1000mL (4 mcg/mL) as the standard dilution 2
• Guidelines suggest 4mg in 250mL (16 mcg/mL) as an alternative adult concentration 1
• Your 5-fold higher concentration increases the risk of inadvertent overdose if pump programming errors occur 4

Monitoring Protocol

Initial Titration Phase

• Monitor blood pressure and heart rate every 5-15 minutes during initial titration 1, 3
• Place an arterial catheter as soon as practical for continuous monitoring 3
• Target mean arterial pressure (MAP) of 65 mmHg for septic shock 1, 3
• For previously hypertensive patients, raise blood pressure no higher than 40 mmHg below pre-existing systolic pressure 2

Ongoing Assessment

• Assess peripheral perfusion regularly (skin temperature, capillary refill) 3
• Monitor for signs of excessive vasoconstriction: cold extremities, decreased urine output 1
• Watch for arrhythmias, particularly at higher doses 3

Dosing Context and Titration

Your starting dose of 0.05 mcg/kg/min is:

• At the lower end of typical starting ranges (0.1-0.5 mcg/kg/min recommended by American Heart Association) 1
• Below the standard pediatric starting dose (0.1-1.0 mcg/kg/min) 1
• May be appropriate for initial cautious titration, but be prepared to increase rapidly if inadequate response 1, 3

Expected Titration

• Typical maintenance dosing ranges from 0.1-2 mcg/kg/min in septic shock 1
• Non-weight-based dosing typically ranges from 2-4 mcg/min (0.5-1 mL/min of standard 4 mcg/mL concentration) 1, 2
• For your concentration, this translates to approximately 1.5-3 mL/hour for maintenance 2

Critical Safety Warnings

Extravasation Management

• If extravasation occurs, immediately infiltrate phentolamine 5-10mg diluted in 10-15mL saline into the affected site to prevent tissue necrosis 1, 3, 2
• Pediatric phentolamine dose: 0.1-0.2 mg/kg up to 10mg 1

Pump Programming Errors

• Never use the loading dose function on infusion pumps for norepinephrine - a documented case resulted in cardiac arrest when 1.8mg was inadvertently delivered in 2 minutes 4
• Double-check all pump settings before initiating infusion 4
• Ensure historical values are cleared from pump memory 4

Drug Compatibility

• Do not mix norepinephrine with sodium bicarbonate or alkaline solutions - it becomes inactivated 1
• Avoid contact with iron salts, alkalis, or oxidizing agents 2

Weight-Based Dosing Consideration

• Research shows obese patients require lower weight-based doses (0.09 mcg/kg/min) compared to non-obese patients (0.13 mcg/kg/min), but similar absolute doses (8-9 mcg/min) 5
• If your patient is obese (BMI ≥30), consider using actual body weight for initial calculation but be prepared that lower weight-based dosing may be adequate 5