Glucose-Insulin Infusion Protocol for NPO Type 1 Diabetes
For Type 1 diabetic patients who are NPO, intravenous insulin infusion is the preferred treatment method, combined with dextrose-containing fluids and potassium supplementation to prevent diabetic ketoacidosis and metabolic decompensation. 1
Critical Principle: Never Withhold All Insulin
- Type 1 diabetic patients require continuous insulin even when NPO to prevent ketoacidosis 1
- Withholding all insulin is a critical error that can lead to diabetic ketoacidosis 1
- Intravenous insulin infusion is specifically preferred for patients with type 1 diabetes mellitus 2
IV Insulin Infusion Protocol
Initiation
- Start continuous intravenous insulin infusion using regular insulin (Humulin R U-100 or equivalent) 3
- Initial infusion rate typically begins at 0.5 units/hour, adjusted to maintain blood glucose near normoglycemia (100-160 mg/dL) 3
- Use validated written or computerized protocols that allow predefined adjustments in infusion rate based on glycemic fluctuations 2
Monitoring Requirements
- Blood glucose monitoring every 1-2 hours during IV insulin infusion 2
- More frequent testing (every 30 minutes to 2 hours) may be required depending on glucose stability 2
- Monitor serum potassium levels closely due to intracellular shift with insulin administration 1
Dextrose and Fluid Management
Fluid Selection
- Administer half-normal saline with dextrose (1/2 DNS) to prevent hypoglycemia 1
- Provide 200-300 grams of dextrose per day as part of fluid management 2
- Dextrose-containing fluids are essential—administering dextrose without concurrent insulin will cause hyperglycemia 1
Potassium Supplementation
- Add 20-30 mEq/L of potassium chloride to IV fluids 1
- Consider using 1/3 potassium phosphate and 2/3 potassium chloride or acetate for balanced replacement 2
- Insulin drives potassium intracellularly, creating risk for dangerous hypokalemia and cardiac arrhythmias without adequate replacement 1
Blood Glucose Targets
- Premeal glucose <140 mg/dL with random glucose <180 mg/dL for noncritically ill patients 1
- Target range of 100-160 mg/dL during IV insulin infusion is appropriate 3
- Avoid glucose <70 mg/dL, which requires immediate treatment and regimen review 2
Alternative: Subcutaneous Insulin Approach (If IV Not Feasible)
If IV insulin infusion cannot be implemented:
- Continue basal insulin at 60-80% of usual dose 1
- For NPH users: give half the usual NPH dose 1
- Add correction insulin every 4-6 hours based on blood glucose monitoring 1
- Never use sliding scale insulin alone—this approach is strongly discouraged and leads to dangerous glucose fluctuations 1, 2
Transition Off IV Insulin
When the patient resumes oral intake:
- Administer subcutaneous basal insulin 2-4 hours before discontinuing IV infusion 2
- Convert to basal insulin at 60-80% of the 24-hour IV insulin dose 2
- Use protocol-driven transition to avoid significant loss of glycemic control 2
- Delay transition to subcutaneous insulin until peripheral edema has resolved, as edema impairs subcutaneous absorption 2, 4
Common Pitfalls to Avoid
- Never stop insulin completely in Type 1 diabetes, even when NPO—this is the most common cause of diabetic ketoacidosis 5, 1
- Do not use sliding scale insulin as sole therapy—it causes rapid glucose fluctuations and increases both hyper- and hypoglycemia risk 1, 2
- Do not provide dextrose without concurrent insulin administration 1
- Do not neglect potassium supplementation—inadequate replacement creates cardiac arrhythmia risk 1
- Do not transition to subcutaneous insulin while patient has significant peripheral edema 2, 4
Monitoring for Complications
- Check for signs of developing ketoacidosis: Kussmaul respirations, blood glucose >200 mg/dL 5
- Monitor urine or blood ketones if glucose exceeds 200 mg/dL 5
- Assess venous pH and anion gap every 2-4 hours if ketoacidosis is suspected 2
- Implement hypoglycemia treatment protocol for any glucose <70 mg/dL 2