How to set an infusion pump for norepinephrine?

How to Set an Infusion Pump for Norepinephrine

Add 4 mg of norepinephrine to 250 mL of D5W to create a concentration of 16 μg/mL, then start the infusion at 0.5 mg/h (approximately 8 μg/min or 0.1 μg/kg/min in a 70 kg adult) and titrate upward based on blood pressure response. 1, 2

Standard Preparation and Concentration

• The FDA-approved standard dilution is 4 mg of norepinephrine in 1000 mL of 5% dextrose, yielding 4 μg/mL 2
• However, the more concentrated preparation of 4 mg in 250 mL D5W (16 μg/mL) is recommended by multiple guideline societies as it reduces fluid volume administration while maintaining accurate dosing 1
• Always use dextrose-containing solutions (D5W or D5NS)—never saline alone—as dextrose protects against oxidation and loss of potency 2

Initial Infusion Rate Settings

• Start at 0.5 mg/h (8 μg/min or approximately 0.1 μg/kg/min in a 70 kg adult) 1
• The FDA label recommends starting at 2-3 mL/min of the 4 μg/mL solution (8-12 μg/min), which aligns with the 0.5 mg/h starting dose 2
• For obese patients, use actual body weight for initial dosing, as they require similar absolute doses but lower weight-based doses compared to non-obese patients 3

Titration Protocol

• Increase by 0.5 mg/h increments every 4 hours as needed, up to a maximum of 3 mg/h 1
• Monitor blood pressure and heart rate every 5-15 minutes during initial titration 1
• Target mean arterial pressure (MAP) of 65 mmHg for septic shock, or maintain systolic BP 80-100 mmHg in other shock states 1, 2
• In previously hypertensive patients, raise BP no higher than 40 mmHg below their baseline systolic pressure 2

Critical Safety Considerations for Pump Programming

• Never use the "loading dose" function on infusion pumps for norepinephrine—a documented case resulted in cardiac arrest when 1.8 mg was inadvertently bolused in 2 minutes due to improper pump settings 4
• Always verify that historical pump values (VTBI and rate) are cleared before programming a new infusion 4
• Use only the primary infusion mode, not loading dose mode, to prevent catastrophic bolus administration 4

Access and Administration Route

• Central venous access is strongly preferred to minimize extravasation risk 1, 2
• If central access is unavailable, peripheral IV can be used temporarily with a large-bore catheter advanced well into the vein 1, 2
• Use an IV drip chamber or metering device to accurately measure flow rate 2

Monitoring Requirements

• Place an arterial line as soon as practical for continuous blood pressure monitoring 1
• Monitor for signs of excessive vasoconstriction: cold extremities, decreased urine output, tissue ischemia 1
• Watch for arrhythmias and hypertension as potential adverse effects 1

Fluid Resuscitation Timing

• Administer crystalloid boluses (minimum 30 mL/kg) before or concurrent with norepinephrine initiation—never delay vasopressors waiting for complete fluid resuscitation in profound hypotension 1, 5
• Consider early norepinephrine (within first hour) in patients with profound hypotension (diastolic BP ≤40 mmHg or diastolic shock index ≥3) 5
• Correct hypovolemia aggressively, as occult volume depletion is the most common cause of refractory hypotension requiring high norepinephrine doses 2

Extravasation Management

• If extravasation occurs, immediately infiltrate phentolamine 5-10 mg diluted in 10-15 mL saline intradermally at the site 1, 2
• Pediatric phentolamine dose: 0.1-0.2 mg/kg up to 10 mg 1

Special Populations

Pediatric Dosing

• Use the "rule of 6": 0.6 × body weight (kg) = mg of norepinephrine diluted to 100 mL saline; then 1 mL/h delivers 0.1 μg/kg/min 1
• Typical pediatric range: 0.1-1.0 μg/kg/min, starting at lowest dose and titrating to effect 1

Anaphylaxis (Alternative Protocol)

• For refractory anaphylaxis not responding to epinephrine, use 1 mg norepinephrine in 100 mL saline (1:100,000 solution) at 30-100 mL/h (5-15 μg/min) 1
• This is only indicated after failure of epinephrine injections and volume resuscitation 1