How is hyperglycemia managed in the Intensive Care Unit (ICU)?

Management of Hyperglycemia in the ICU

Hyperglycemia in the ICU should be managed with intravenous insulin infusion targeting blood glucose levels between 140-180 mg/dL (7.8-10.0 mmol/L) to optimize patient outcomes while minimizing hypoglycemia risk. 1

Target Glucose Levels

• Initiate insulin therapy when blood glucose levels exceed 180 mg/dL (10 mmol/L) in critically ill patients 1
• Maintain glucose values between 140-180 mg/dL (7.8-10.0 mmol/L) for most ICU patients 1
• More stringent targets (110-140 mg/dL or 6.1-7.8 mmol/L) may be appropriate only for select patients, such as cardiac surgery patients or those with acute ischemic cardiac/neurological events, but only when these targets can be achieved without significant hypoglycemia 1
• Avoid glucose targets below 110 mg/dL (6.1 mmol/L) due to increased risk of hypoglycemia without additional clinical benefit 1

Insulin Administration Method

• Continuous intravenous insulin infusion (CII) is the preferred method for glycemic control in the ICU 1
• IV insulin's short half-life (<15 min) allows for rapid dose adjustments in response to changes in clinical status or nutrition 1
• CII typically achieves target glucose levels within 4-8 hours 1
• Subcutaneous insulin should be avoided in critically ill patients, particularly during hypotension or shock 1

Implementation Strategies

• Computer-based algorithms for insulin infusion management have shown benefits including:
  • Lower rates of hypoglycemia 1, 2
  • Reduced glycemic variability 1, 2
  • Higher percentage of glucose readings within target range 1, 2
• However, these algorithms have not demonstrated reductions in hospital complications or mortality compared to standard regimens 1, 2

Monitoring and Safety Considerations

• Frequent blood glucose monitoring is essential to prevent hypoglycemia 1, 3
• Hypoglycemia (blood glucose <70 mg/dL or 3.9 mmol/L) is a significant adverse event that must be avoided 1, 3
• Severe hypoglycemia (<40 mg/dL or 2.2 mmol/L) is associated with cognitive impairment and increased mortality 1, 3
• Signs of hypoglycemia may include sweating, anxiety, tremor, hunger, confusion, and in severe cases, seizures or unconsciousness 3
• Potassium levels should be carefully monitored, as hypokalaemia is common during treatment of hyperglycemic crises 1

Special Considerations

• For patients with ischemic events (myocardial infarction or stroke), rapid control of glucose values is warranted, but intensive lowering has not shown additional benefit 1
• Patients with hyperglycemic crises (diabetic ketoacidosis or hyperosmolar hyperglycemic state) should receive continuous insulin infusion according to specific protocols 1
• When transitioning from IV to subcutaneous insulin (once patients are stable), consider factors such as:
  • Stable glucose measurements for at least 4-6 hours 1
  • Resolution of acidosis in diabetic ketoacidosis 1
  • Hemodynamic stability (not on vasopressors) 1
  • Stable nutrition plan 1

Common Pitfalls to Avoid

• Using sliding scale insulin as the sole regimen, which results in undesirable glycemic fluctuations 1, 4
• Setting overly stringent glucose targets (<110 mg/dL), which increases hypoglycemia risk without improving outcomes 1
• Failing to adjust insulin doses in response to changes in clinical status, nutrition, or medication regimens 3, 4
• Inadequate monitoring of glucose levels, particularly during insulin infusion 1, 2
• Not recognizing that certain medications (corticosteroids, vasopressors) can significantly increase insulin requirements 3, 4

By following these evidence-based guidelines for managing hyperglycemia in the ICU, clinicians can help reduce complications and improve outcomes for critically ill patients while minimizing the risks associated with both hyperglycemia and hypoglycemia.