Glycemic Control in the ICU

Steven Podnos MD

Hyperglycemia

• Occurs in up to 50% of ICU patients due to underlying DM , steroids, and/or stress of illness

• Is a MARKER of worse outcomes in many different ICU illnesses

Control of Glucose in ICU

• One early study (van den Berghe) found a decreased mortality with intensive control of glucose (IIT), but was limited to Cardiac Surgery patients , often on TPN

• Two large recent trials of IIT were stopped due to 1) lack of benefit with IIT and 2) increased hypoglycemia

Stress Hormones and Hyperglycemia

• Glucagon,Glucocorticoids,Norepinephrine• Epinephrine• Tumor Necrosis factor• All these hormones are secreted with stress

of illness and produce elevated glucose through various methods

Ill Effects of Hyperglycemia

• Direct Immune suppression• Excess insulin causes cellular damage• Direct cellular toxicity and release of

inflammatory mediators in presence of hyperglycemia

Hypoglycemia

• Brain requires adequate glucose levels or coma/death results in minutes

Why is Consensus Changing?

• Early studies suggested benefit to Intensive Insulin Therapy (IIT)

• Later studies do not-some show harm from hypoglycemia and no mortality benefit

• Studies differ in many variables: SICU vs MICU, parenteral vs enteral nutrition, degree of illness (APACHE 2 scores), intensity of control

• More studies pending

Recommendations

• Current consensus seems to be liberalizing glucose control to 140-180.

• Evidence weak of benefit• Some suggest it is swings in glucose levels that

may be harmful rather than absolute levels.• May be more appropriate to use constant

insulin drip to keep levels higher than sliding scale which has more glucose fluctuations (unproven)