What should the NPH (Neutral Protamine Hagedorn) insulin dose be for a patient with a 1:10 insulin-to-carbohydrate ratio and a daily carbohydrate intake of 291 grams?

NPH Insulin Dosing for Tube Feeding with 291g Carbohydrates Daily

For a patient receiving 291 grams of carbohydrates via tube feeding over 24 hours with a 1:10 insulin-to-carbohydrate ratio, the NPH insulin dose should be approximately 14 units administered in the morning, which represents roughly half of the calculated total daily insulin requirement of 29 units from the carbohydrate load alone. 1

Calculating the Base NPH Requirement

Step 1: Determine Total Prandial Insulin Need

• With 291g carbohydrates and a 1:10 ratio, the patient requires approximately 29 units of insulin to cover the carbohydrate intake 2
• In physiologic insulin secretion, approximately half of daily insulin constitutes basal coverage 3

Step 2: Calculate NPH Dose

• The NPH dose should be approximately 14-15 units (roughly 50% of the 29-unit total requirement) 3
• This aligns with the guideline recommendation that basal insulin should constitute approximately 47% of total daily dose 4
• Morning administration is preferred to match the typical peak action of NPH at 4-6 hours 1, 2

Special Considerations for Continuous Enteral Nutrition

NPH Dosing Strategy for 24-Hour Tube Feeding

• For patients receiving continuous enteral nutrition over 24 hours, NPH can be administered two or three times daily rather than once daily 1
• Consider splitting the dose: 2/3 in the morning (approximately 10 units) and 1/3 in the evening (approximately 5 units) to provide more consistent coverage 1, 5
• This split-dose approach prevents gaps in insulin coverage during continuous carbohydrate delivery 1

Monitoring Requirements

• Blood glucose should be monitored every 2-4 hours while receiving tube feeding to guide insulin adjustments 1, 2
• Target blood glucose range should be 80-180 mg/dL 2
• Pay particular attention to patterns of hyperglycemia or hypoglycemia at specific times to adjust the timing and distribution of NPH doses 2

Dose Adjustment Protocol

For Persistent Hyperglycemia

• Increase the NPH dose by 2 units every 3 days until target blood glucose is achieved 1, 5
• More aggressive increases may be needed if blood glucose consistently exceeds 200 mg/dL 2

For Hypoglycemia

• If hypoglycemia occurs, lower the NPH dose by 10-20% 1, 2
• This is particularly important in patients receiving continuous tube feeding, as they are at higher risk for unrecognized hypoglycemia 1

Common Pitfalls to Avoid

• Do not rely solely on a single daily NPH dose for 24-hour continuous tube feeding - this often results in inadequate coverage during portions of the day 1
• Avoid using only correction insulin without basal coverage - this reactive approach leads to poor glycemic control 2
• Do not abruptly discontinue or significantly reduce NPH if tube feeding is temporarily interrupted - instead, reduce by 50% and monitor closely, as complete cessation may cause rebound hyperglycemia 6
• Monitor closely for hypoglycemia if tube feeding is stopped unexpectedly, as NPH will continue to act for 12-16 hours after administration 1