How is noradrenaline (norepinephrine) initiated in a patient with hypotension?

Noradrenaline Administration in Hypotensive Patients

Noradrenaline should be initiated as a continuous intravenous infusion at a starting dose of 0.2-1.0 μg/kg/min without a bolus dose, titrated to achieve a target blood pressure sufficient to maintain vital organ perfusion (typically 80-100 mmHg systolic). 1, 2

Initial Assessment and Preparation

Before starting noradrenaline:

• Ensure adequate volume resuscitation has been attempted first, as administering noradrenaline to hypovolemic patients can worsen tissue ischemia 2
• Insert a central venous catheter, as noradrenaline should be infused into a large vein to prevent extravasation 2
• Establish continuous arterial blood pressure monitoring via an arterial line 1
• Determine the underlying cause of hypotension to guide overall management

Preparation and Administration Protocol

1. Preparation of infusion:

   • Standard concentration: 4 mg noradrenaline in 250 mL compatible solution (16 μg/mL)
   • Use D5W or 0.9% sodium chloride as diluent

2. Initial dosing:

   • Start at 0.2 μg/kg/min without a bolus dose 1
   • For a 70 kg adult, this equates to approximately 7-14 μg/min

3. Titration strategy:

   • Titrate every 3-5 minutes based on blood pressure response
   • Increase dose gradually until target blood pressure is achieved
   • Average maintenance dose ranges from 2-4 μg/kg/min 1
   • Maximum dose typically up to 1.0 μg/kg/min 1

4. Target parameters:

   • Systolic BP 80-100 mmHg or
   • Mean arterial pressure (MAP) ≥65 mmHg 1
   • Adjust target based on patient's baseline BP and clinical condition

Monitoring During Administration

• Continuous arterial blood pressure monitoring
• Heart rate and ECG monitoring (watch for arrhythmias) 2
• Urine output (indicator of adequate renal perfusion)
• Frequent assessment of peripheral circulation and skin temperature
• Monitor for signs of extravasation at infusion site
• Assess tissue perfusion markers (lactate, capillary refill time) 3

Special Considerations

• Cardiac dysfunction: Noradrenaline can increase cardiac output in hypotensive patients through increased preload and contractility, even in those with reduced ejection fraction 4
• Weaning: Never stop noradrenaline abruptly as this may cause rebound hypotension; gradually reduce the dose while monitoring hemodynamic response 2
• Extravasation management: If extravasation occurs, infiltrate the area with 5-10 mg phentolamine in 10-15 mL of normal saline within 12 hours to prevent tissue necrosis 2

Common Pitfalls to Avoid

• Inadequate fluid resuscitation: Always ensure adequate volume status before or concurrent with starting noradrenaline 2
• Peripheral administration: Avoid peripheral administration when possible due to risk of extravasation and tissue necrosis
• Fixed dose approach: Failure to titrate based on individual response
• Abrupt discontinuation: Always taper gradually to avoid rebound hypotension 2
• Excessive doses: Using doses higher than needed may cause excessive vasoconstriction and compromise tissue perfusion

Noradrenaline is a powerful vasopressor that requires careful administration and monitoring, but when used appropriately, it can effectively restore blood pressure and improve tissue perfusion in hypotensive patients 4, 3.