Management of Hyperglycemia in Critically Ill Patients on Basal-Bolus Regimens
For critically ill patients with hyperglycemia in the ICU, you should transition from basal-bolus subcutaneous insulin to continuous intravenous insulin infusion, as IV insulin is the preferred and guideline-recommended approach for this population. 1, 2
When to Use IV Insulin vs. Subcutaneous Insulin
Continuous IV insulin infusion is mandatory for:
- Patients with type 1 diabetes mellitus 1
- Hemodynamically unstable patients with hyperglycemia 1
- Patients on vasopressors 1
- Patients with changing clinical status (hypothermia, edema, frequent interruption of dextrose intake) 1
- Severe DKA or hyperosmolar hyperglycemic state 1, 2
- Perioperative management during major surgery 2
Subcutaneous basal-bolus insulin may be considered only for:
- Stable ICU patients who have achieved glycemic control on IV insulin and are ready for transition 1
- Selected ICU patients who are hemodynamically stable, not on vasopressors, without peripheral edema, and with consistent nutritional intake 1
Glycemic Targets in the ICU
Target glucose range of 140-180 mg/dL for critically ill patients 1, 3, 4
- Targeting euglycemia (80-110 mg/dL) substantially increases the risk of iatrogenic hypoglycemia and is discouraged 1
- Blood glucose levels >180 mg/dL increase the risk of hospital complications 3
- Glucose targets <140 mg/dL should not be aggressively pursued as this increases hypoglycemia risk without improving outcomes 2
IV Insulin Preparation and Administration
Prepare continuous insulin infusion at 1 unit/mL concentration 1
- Prime new tubing with a 20-mL waste volume before initiating therapy 1
- Use standardized concentration across your institution 1
Monitoring Requirements
Point-of-care glucose testing every 1-2 hours initially when on IV insulin 2
- Increase frequency to every 1-2 hours if glucose >250 mg/dL or <70 mg/dL 2
- Basic metabolic panel (sodium, potassium, glucose, creatinine) every 2-4 hours initially 2
- Monitor for hypokalemia and replace potassium if <4.0 mEq/L before starting insulin 2
Transitioning from IV to Subcutaneous Insulin
When transitioning stable ICU patients to subcutaneous therapy, use a protocol-driven basal-bolus regimen and administer the first dose of basal insulin 2-4 hours before stopping the IV infusion 1
Calculate the total daily dose based on the average hourly IV insulin rate over the previous 24 hours:
- Multiply the average hourly IV insulin rate by 20-24 to get the total daily subcutaneous dose 5
- Split this dose: 50% as basal insulin (given once or twice daily) and 50% as rapid-acting prandial insulin (divided before meals) 5, 6
Do not transition to subcutaneous insulin until:
- Patient is hemodynamically stable 1
- Off vasopressors 1
- Peripheral edema has resolved 1
- No planned interruptions of nutrition for procedures 1
- Able to maintain blood glucose <180 mg/dL 1
Critical Pitfalls to Avoid
Never use sliding-scale insulin alone as the sole regimen in critically ill patients - it is associated with poor glycemic control and increased complications 2, 7
Never use premixed insulin (70/30) in the hospital setting - it has an unacceptably high rate of hypoglycemia 1, 2
Never stop IV insulin before administering subcutaneous basal insulin - this prevents rebound hyperglycemia and recurrence of ketoacidosis 1
Never continue subcutaneous insulin in unstable critically ill patients - absorption is unpredictable in the presence of hypoperfusion, edema, or vasopressor use 1
Hypoglycemia Risk Management
The risk of hypoglycemia with basal-bolus insulin is 4-6 times higher than with sliding scale insulin alone 1