Should I reduce the evening NPH (Neutral Protamine Hagedorn) insulin dose in a patient on continuous tube feeding and receiving twice daily (bid) NPH insulin?

Managing NPH Insulin in Patients on Continuous Tube Feeding

Yes, you should reduce the evening NPH insulin dose in a patient on continuous tube feeding to prevent nocturnal hypoglycemia.

Rationale for NPH Dose Reduction

NPH insulin has a peak action 4-10 hours after administration, which creates a significant risk of hypoglycemia during the night when given in the evening. For patients on continuous tube feeding, this risk is particularly important to manage since:

• Continuous enteral nutrition provides a steady carbohydrate load that requires consistent insulin coverage 1
• The peak action of evening NPH may not align well with the steady glucose influx from continuous tube feeding
• Nocturnal hypoglycemia is a significant risk factor for subsequent hypoglycemic events 1

Recommended Approach

1. Adjust NPH dosing schedule:

   • Reduce the evening NPH dose by approximately 20% initially 1
   • Consider splitting NPH to every 8 or 12 hours for more consistent coverage 1

2. Distribution of NPH doses:

   • When converting to twice-daily NPH for continuous tube feeding:
     • Use approximately 80% of the current total NPH dose
     • Administer 2/3 in the morning and 1/3 in the evening 1
     • This distribution helps reduce the risk of nocturnal hypoglycemia while maintaining glycemic control

3. Monitor and adjust:

   • Check blood glucose every 6 hours initially after making changes
   • Target blood glucose range of 80-180 mg/dL for hospitalized patients 1
   • Make further adjustments based on glucose patterns

Special Considerations

• If hypoglycemia persists despite NPH dose reduction, consider:

  • Further reducing the evening dose
  • Switching to a basal analog insulin which provides more consistent coverage with less peak effect 1
  • Adding a 10% dextrose infusion if enteral nutrition is interrupted to prevent hypoglycemia 1

• For patients with recurrent hypoglycemia:

  • Evaluate for overbasalization (basal dose >0.5 units/kg/day) 1
  • Consider that 78% of patients with hypoglycemia are using basal insulin, with hypoglycemia peaking between midnight and 6:00 A.M. 1

Pitfalls to Avoid

• Don't maintain the same NPH dosing schedule used for patients on regular meals when managing patients on continuous tube feeding
• Avoid delaying dose adjustments after hypoglycemic events - studies show 75% of patients did not have basal insulin doses changed after hypoglycemia 1
• Don't forget to restart insulin if tube feeding is interrupted - patients with type 1 diabetes must continue to receive basal insulin even if feedings are discontinued 1
• Avoid using only once-daily NPH for continuous tube feeding, as this creates uneven coverage that doesn't match the steady carbohydrate delivery

By reducing the evening NPH dose and potentially transitioning to a twice-daily NPH regimen with appropriate distribution (2/3 morning, 1/3 evening), you can better match insulin action to the continuous carbohydrate delivery from tube feeding and significantly reduce the risk of dangerous nocturnal hypoglycemia.