When is it appropriate to stop intravenous (IV) insulin therapy?

When to Stop IV Insulin Therapy

IV insulin therapy should be stopped when blood glucose levels are stable for at least 24 hours, the patient has resumed oral feeding, and the IV insulin infusion rate is <3 U/h, followed by immediate transition to subcutaneous insulin. 1, 2

Criteria for Discontinuing IV Insulin

The decision to stop IV insulin therapy should follow these specific parameters:

• Glycemic stability: Blood glucose levels should be stable for at least 24 hours 1, 2
• Nutritional status: Patient has resumed oral feeding 1
• Insulin requirements: IV insulin infusion rate is <3 U/h (higher rates indicate insulin resistance and increased risk of postoperative complications) 1
• Blood glucose target: Stable blood glucose levels <10 mmol/L (180 mg/dL) 1

Transition Protocol from IV to Subcutaneous Insulin

Step 1: Preparation

• Calculate the total daily insulin requirement based on the previous 6-8 hours of stable IV insulin administration 2
• Administer subcutaneous basal insulin 2 hours before stopping the IV infusion to prevent rebound hyperglycemia 2

Step 2: Dosing Calculation

• Convert 50-60% of the total 24-hour IV insulin dose to subcutaneous insulin 1, 2, 3
  • Research shows the 50-59% conversion group achieved the highest rate of blood glucose concentrations in target range (68%) compared to other conversion percentages 3
• Divide the calculated dose:
  • 50% as basal (long-acting) insulin
  • 50% as bolus (rapid-acting) insulin divided between meals 1, 2

Step 3: Administration Timing

• Administer the first dose of long-acting insulin immediately after stopping the IV infusion 1
• Best time for administration is 20:00 hours; if earlier, adapt the dose and give the second injection at 20:00 hours 1
• Administer the first dose of rapid-acting insulin at the first meal, adjusting for carbohydrate content 1

Special Considerations

For Patients with Insulin Pumps

• For patients on insulin pump therapy:
  • Reconnect the personal pump as soon as the patient can manage autonomously 1
  • If the patient cannot manage the pump, initiate a basal-bolus subcutaneous insulin regimen 1
  • When transitioning back to pump therapy, connect the pump and infuse basal rate for at least 2 hours before stopping IV insulin 1

For Short-Term IV Insulin Use (<24 hours)

• For patients not previously treated with insulin who received IV insulin for <24 hours:
  • Start subcutaneous insulin at 0.5-1 IU/kg (half as basal, half as bolus) 1
  • Give only half of the calculated rapid-acting dose if the meal is light 1

For Patients with High Insulin Requirements

• If IV insulin output is ≥5 IU/h, leave the IV insulin in place as this indicates major insulin resistance 1
• If IV insulin output is ≤0.5 IU/h, consider stopping insulin therapy 1

Monitoring After Transition

• Monitor blood glucose before meals and at bedtime 2
• Continue monitoring for at least 48 hours after transition, as glycemic control may deteriorate rapidly 4
• Check for hypoglycemia (<70 mg/dL or <3.9 mmol/L) 2
• If hypoglycemia occurs, review and adjust the insulin regimen 2

Common Pitfalls to Avoid

1. Abrupt discontinuation: Never stop IV insulin without overlapping with subcutaneous insulin, as this can lead to rebound hyperglycemia 2, 4

2. Inadequate dose conversion: Underdosing (0-49% of IV requirements) results in the lowest rate of target glucose achievement (46%) 3

3. Delayed transition: Prolonged IV insulin therapy increases the risk of complications and extends hospital stay 5

4. Ignoring patient-specific factors: Age, glycemic variability, and pre-admission glycemic control affect hypoglycemia risk during transition 6

5. Insufficient monitoring: Failure to monitor closely during the first 48 hours after transition can miss deteriorating glycemic control 4