Perioperative Glycemic

Surgery is a metabolic stressor. Anesthesia, tissue injury, pain, infection, and critical illness stimulate cortisol, catecholamines, glucagon, growth hormone, and inflammatory cytokines. These signals tell the liver to release glucose while making muscle and fat cells less responsive to insulin. The result is hyperglycemia, even in a person with no history of diabetes. A patient whose usual glucose is normal may develop marked stress hyperglycemia after a major procedure, and that finding is not benign. Elevated glucose impairs leukocyte function, promotes infection, slows wound healing, and is associated with longer hospitalization and higher mortality. The nurse should not assume that postoperative hyperglycemia is expected and therefore harmless. It may reflect the expected stress response, but it can also reveal untreated diabetes, inadequate insulin replacement, infection, steroid effect, or evolving diabetic ketoacidosis (DKA).