Insulin Infusion Management

Protocol Development and Implementation

• The American Association for Critical Care Medicine recommends using a standardized insulin infusion protocol or algorithm to guide therapy, evaluating the amount and timing of carbohydrate intake when calculating insulin requirements, and consistent intake of nutrition simplifies glycemic management during insulin infusion, while avoiding overfeeding, which may worsen hyperglycemia 1
• Insulin is a high-risk medication requiring a systems-based approach to reduce errors, and common errors include failing to adjust insulin rates promptly in response to changing glucose levels, not accounting for changes in nutritional intake or steroid administration, inadequate monitoring frequency, especially during periods of instability, transitioning to subcutaneous insulin too early or without proper overlap, and relying solely on sliding scale insulin without basal coverage when transitioning to subcutaneous insulin 2

Transitioning to Subcutaneous Insulin

• Transition from IV insulin to subcutaneous insulin when blood glucose levels are stable, IV insulin infusion rate is low, patient is hemodynamically stable, patient has a stable nutrition plan, and normal anion gap (in cases of diabetic ketoacidosis), as recommended by the American Diabetes Association and other guideline societies 2, 3, 4, 5
• The American College of Critical Care Medicine recommends maintaining blood glucose between 140-180 mg/dL for most critically ill patients, with more stringent goals (110-140 mg/dL) for select patients such as cardiac surgery patients, patients with acute ischemic cardiac events, and patients with acute neurological events 3, 4, 5
• For critically ill patients with persistent hyperglycemia, the American College of Critical Care Medicine recommends initiating insulin therapy when blood glucose levels reach ≥180 mg/dL on two consecutive readings, and continuous intravenous insulin infusion at a concentration of 1 unit/mL as the initial approach 6, 1
• The American Diabetes Association recommends monitoring blood glucose every hour or more frequently during periods of glycemic instability, and extending monitoring intervals once stable, but maintaining frequent monitoring during the first 24-48 hours 6, 2
• Calculate the total daily subcutaneous insulin dose by using 50-60% of the 24-hour IV insulin requirement, with half given as basal insulin and half divided into prandial doses, or alternatively, calculate total daily insulin (TDI) based on the IV insulin rate during the previous 6-8 hours when glucose was stable, using a validated approach 7, 5

Insulin Regimens and Dosing

• The most physiologic approach to insulin therapy is a basal-bolus regimen, which consists of basal insulin (long-acting insulin) once or twice daily, bolus insulin (rapid-acting insulin) before meals, and correction doses (additional rapid-acting insulin) for hyperglycemia, as recommended by The Lancet Diabetes and Endocrinology 2
• Sliding scale insulin alone (without basal insulin) is associated with poor glycemic control and is not recommended, except for patients without diabetes who have mild stress hyperglycemia, as stated by The Lancet Diabetes and Endocrinology 2
• For patients receiving high-dose dexamethasone, multiple-dose insulin therapy starting at 1-1.2 U/kg per day is recommended, with 25% basal and 75% prandial insulin 2
• Blood glucose should be checked before meals and at bedtime, and more frequently (every 4-6 hours) during the first 24 hours after transition, with a target glucose range of 140-180 mg/dL for most hospitalized patients, as recommended by The Lancet Diabetes and Endocrinology 2

Special Considerations

• A hypoglycemia management protocol should be implemented, with treatment of hypoglycemia using 15-20g of fast-acting carbohydrate for blood glucose <70 mg/dL, and administration of glucose immediately for blood glucose <60 mg/dL, as suggested by the guidelines 2
• For insulin pump users undergoing minor procedures, the pump may continue with hourly monitoring, as recommended by the British Journal of Anaesthesia 8
• For major or emergency surgery: discontinue pump and transition to IV insulin, as recommended by the British Journal of Anaesthesia 8
• Reduce basal insulin by 25% the night before surgery to help achieve perioperative glucose targets with less risk of hypoglycemia 5

Diabetic Ketoacidosis (DKA) and Hyperosmolar Hyperglycemic State (HHS)

9, 10, 11

• In critically ill patients with DKA, an initial insulin bolus of 0.15 U/kg followed by continuous infusion at 0.1 U/kg/hour is recommended, as stated by the Diabetes Care society 10