How to administer noradrenaline (norepinephrine) in 5% dextrose via microdrip in a 40 kg patient with septic shock without a central line (central venous catheter)?

Administration of Noradrenaline in Septic Shock via Peripheral Microdrip

When central venous access is unavailable, noradrenaline can be safely administered through a large peripheral vein using a microdrip system with careful monitoring for extravasation.

Preparation of Noradrenaline Solution

1. Standard Dilution:

   • Add 4 mg (4 mL) of noradrenaline to 1,000 mL of 5% Dextrose solution to produce a 4 mcg/mL concentration 1
   • For a 40 kg patient, this is the recommended dilution for peripheral administration

2. Microdrip Setup:

   • Use a microdrip infusion set (60 drops = 1 mL)
   • Ensure the peripheral IV is placed in a large vein, preferably in the forearm or antecubital fossa 2
   • Use at least a 20G catheter or larger to minimize extravasation risk 3

Dosing and Rate Calculation

1. Initial Dosing:

   • Starting dose: 0.05-0.1 μg/kg/min 4
   • For a 40 kg patient: 2-4 μg/min

2. Drop Rate Calculation:

   • Formula: (Dose in μg/min ÷ Concentration in μg/mL) × 60 drops/mL
   • Example for 2 μg/min: (2 μg/min ÷ 4 μg/mL) × 60 drops/mL = 30 drops/min
   • Example for 4 μg/min: (4 μg/min ÷ 4 μg/mL) × 60 drops/min = 60 drops/min

3. Titration:

   • Titrate by 0.05-0.1 μg/kg/min (2-4 μg/min for a 40 kg patient) every 5-15 minutes 4
   • Target MAP ≥ 65 mmHg 5, 4
   • Typical maintenance dose: 2-4 μg/min (0.05-0.1 μg/kg/min) 1

Monitoring and Safety Considerations

1. Frequent Monitoring:

   • Check blood pressure every 2-5 minutes until target MAP is achieved, then every 5 minutes 1
   • Monitor for signs of extravasation: pain, swelling, blanching at infusion site 3
   • Assess tissue perfusion markers: lactate levels, urine output, mental status 4

2. Extravasation Prevention:

   • Avoid using veins in the leg, especially in elderly or patients with vascular disease 1
   • Regularly assess IV site integrity at least hourly 3
   • If extravasation occurs, infiltrate the area with 10-15 mL saline containing 5-10 mg of phentolamine 5, 1

3. Risk Factors for Extravasation:

   • Peripheral edema
   • Infusion duration >24 hours
   • Concentration >60 mg/L
   • Infusion rate >0.3 μg/kg/min
   • Needle size <20G 3

Special Considerations for Peripheral Administration

1. Duration Limitations:

   • Plan for central line placement if vasopressor therapy is expected to continue >24 hours 3
   • The incidence of extravasation with peripheral noradrenaline is approximately 4% 2

2. Alternative Options:

   • If noradrenaline is unavailable, epinephrine can be used as an alternative 5
   • Consider adding vasopressin if high doses of noradrenaline are required 4

3. Fluid Resuscitation:

   • Ensure adequate fluid resuscitation before or concurrent with noradrenaline initiation (minimum 30 mL/kg crystalloids) 4
   • Address hypovolemia before starting noradrenaline therapy 1

Practical Tips

• Use the largest peripheral vein available, preferably in the forearm
• Consider ultrasound guidance for peripheral IV placement if available
• Prepare for transition to central access if prolonged vasopressor therapy is anticipated
• Have phentolamine readily available for immediate treatment of extravasation
• Monitor the IV site continuously and change to a new site at first sign of problems
• Document vital signs, infusion rate, and site assessment regularly

Remember that while peripheral administration of noradrenaline is acceptable when central access is unavailable, efforts should be made to establish central venous access if prolonged vasopressor therapy is anticipated.