What is the protocol for preparing and administering an insulin infusion?

Insulin Infusion Preparation and Administration Protocol

To prepare an insulin infusion, dilute regular insulin to a concentration of 1 unit/mL in normal saline, prime the infusion line with 20 mL of the solution before connecting to the patient, and administer according to validated protocols with appropriate glucose monitoring. 1

Preparation of Insulin Infusion

Materials Needed:

• Regular insulin (Humulin R or equivalent)
• 0.9% Normal Saline solution
• Infusion bag (typically 100 mL)
• Infusion tubing
• Alcohol swabs

Step-by-Step Preparation:

1. Verify insulin type: Ensure you are using regular insulin (Humulin R), which should appear clear and colorless 2

2. Prepare the solution:

   • Add 100 units (1 mL) of regular insulin to 99 mL of 0.9% normal saline to create a 1 unit/mL concentration 1
   • For higher concentration needs (e.g., calcium channel blocker overdose), a 16 units/mL concentration can be prepared by adding 800 units (8 mL) of regular insulin to 42 mL of 0.9% saline 3

3. Mix the solution:

   • Gently invert the bag several times to ensure proper mixing
   • Avoid vigorous shaking which can create bubbles and affect accurate dosing 4

4. Prime the infusion line:

   • Run 20 mL of the insulin solution through the infusion line before connecting to the patient 1, 5
   • This is critical as insulin adsorbs to plastics in IV tubing, and a 20 mL prime is sufficient to saturate binding sites and ensure accurate dosing 5

Administration Protocol

Infusion Setup:

• Label the infusion bag clearly with concentration, date, time of preparation, and expiration
• Use a dedicated infusion line for insulin administration
• Connect to an infusion pump for precise control of administration rate

Dosing Guidelines:

• For diabetic ketoacidosis (DKA): Initial bolus of 0.15 units/kg followed by continuous infusion at 0.1 units/kg/hour 1
• For hyperglycemia in critically ill patients: Start infusion when glucose >180 mg/dL, targeting 140-180 mg/dL 1
• Adjust rates according to validated protocols, aiming to reduce glucose by 50-75 mg/dL per hour 1

Monitoring Requirements:

• Check blood glucose initially every hour until stable, then every 2-4 hours
• Monitor potassium levels closely, as hypokalemia is a contraindication to insulin therapy 1
• Assess for signs of hypoglycemia, especially when glucose levels begin to normalize

Special Considerations

Storage:

• Unopened insulin should be refrigerated (36-46°F, 2-8°C) 4
• Insulin in use may be kept at room temperature (59-86°F, 15-30°C) for up to 30 days 4
• If room temperature exceeds 86°F (30°C), store insulin in current use in a refrigerator 4

Stability:

• Prepared insulin infusions at 1 unit/mL concentration remain stable for 24 hours at room temperature
• Higher concentrations (16 units/mL) remain stable for up to 14 days when refrigerated or at room temperature 3

Common Pitfalls to Avoid:

1. Inadequate priming: Failure to prime with sufficient volume (20 mL) can lead to inaccurate dosing due to insulin adsorption to tubing 5
2. Incorrect concentration: Using wrong insulin concentration can lead to serious dosing errors
3. Improper mixing: Inadequate mixing can lead to inconsistent insulin delivery
4. Failure to monitor: Not monitoring glucose frequently can lead to hypoglycemia or inadequate treatment

By following this protocol, you can ensure safe and effective administration of insulin infusions while minimizing risks of dosing errors and complications.