Why is 5% dextrose with 6 units of insulin given to diabetic patients who are Nothing Per Oral (NPO)?

From the Guidelines

5% dextrose with 6 units of insulin is given to diabetic patients who are NPO to maintain glucose homeostasis and prevent hyperglycemia, as this combination provides necessary calories and prevents ketosis while the insulin helps facilitate glucose uptake by cells. The typical regimen involves adding 6 units of regular insulin to 500mL of 5% dextrose solution, infused at a rate of approximately 100mL/hour, though this may be adjusted based on blood glucose monitoring 1. This approach is particularly important for insulin-dependent diabetics who risk hypoglycemia if insulin is given without glucose, or hyperglycemia if glucose is given without insulin.

Key Considerations

• The solution provides approximately 100 calories per hour, helping maintain energy requirements during the NPO period.
• Blood glucose should be monitored every 4-6 hours while on this infusion, with adjustments made as needed.
• A basal plus correction insulin regimen is the preferred treatment for patients with poor oral intake or who are taking nothing by mouth (NPO) 1.
• The dose of insulin for the total daily nutritional component may be calculated as 1 unit of insulin for every 10–15 g carbohydrate in the formula 1.

Administration and Monitoring

• The infusion rate and insulin dose may need to be adjusted based on the patient's blood glucose levels and clinical condition.
• It is essential to monitor the patient's blood glucose levels regularly to prevent hypoglycemia or hyperglycemia.
• The patient's electrolyte levels and fluid status should also be monitored during the infusion.
• If enteral nutrition is interrupted, a 10% dextrose infusion must be started immediately to prevent hypoglycemia and to allow time to select more appropriate insulin doses 1.

From the FDA Drug Label

For intravenous use, Humulin R U-100 should be used at concentrations from 0.1 unit/mL to 1 unit/mL in infusion systems with the infusion fluids 0.9% sodium chloride using polyvinyl chloride infusion bags.

The FDA drug label does not answer the question.

From the Research

Administration of 5% Dextrose with Insulin

• The administration of 5% dextrose with insulin to diabetic patients who are Nothing Per Oral (NPO) is a common practice to avoid hypoglycemia 2.
• Studies have shown that dextrose is effective in treating hypoglycemia, and its administration with insulin can help prevent hypoglycemia 3, 4, 5.
• The use of 5% dextrose with insulin may be preferred over other concentrations of dextrose, such as 50% dextrose, as it can provide a more gradual increase in blood glucose levels and reduce the risk of hyperglycemia 4, 5.

Blood Glucose Response

• The blood glucose response to dextrose administration can vary depending on several factors, including the dose and concentration of dextrose, the patient's baseline blood glucose level, and the presence of diabetes 6, 4.
• Studies have shown that the administration of 5% dextrose with insulin can result in a significant increase in blood glucose levels, with a median increase of 24 mg/dL over 6 hours 2.
• However, the use of 5% dextrose with insulin can also increase the risk of hypoglycemia, particularly in patients with diabetes, and frequent blood glucose monitoring is recommended to prevent this complication 2, 6.

Comparison of Dextrose Concentrations

• Studies have compared the effectiveness of different concentrations of dextrose, including 10% and 50% dextrose, in the treatment of hypoglycemia 4, 5.
• The results of these studies suggest that 10% dextrose may be as effective as 50% dextrose in resolving symptoms and correcting hypoglycemia, with fewer adverse events and a lower risk of hyperglycemia 4, 5.
• However, the use of 10% dextrose may require larger volumes and longer administration times compared to 50% dextrose, which can be a disadvantage in certain situations 5.