Glycemic control in cardiac surgery: implementing an evidence-based insulin infusion protocol.

BACKGROUND: Acute hyperglycemia following cardiac surgery increases the risk of deep sternal wound infection, significant early morbidity, and mortality. Insulin infusion protocols that target tight glycemic control to treat hyperglycemia have been linked to hypoglycemia and increased mortality. Recently published studies examining glycemic control in critical illness and clinical practice guidelines from professional organizations support moderate glycemic control.

OBJECTIVES: To measure critical care nurses' knowledge of glycemic control in cardiac surgery before and after education. To evaluate the safety and effectiveness of an evidence-based insulin infusion protocol targeting moderate glycemic control in cardiac surgery patients.

METHODS: This evidence-based practice change was implemented in the cardiovascular unit in a community teaching hospital. Nurses completed a self-developed questionnaire to measure knowledge of glycemic control. Blood glucose data, collected (retrospectively) from anesthesia end time through 11:59 PM on postoperative day 2, were compared from 2 months before to 2 months after the practice change.

RESULTS: Nurses' knowledge (test scores) increased significantly after education (pretest mean = 53.10, SD = 11.75; posttest mean = 79.10, SD = 12.02; t54 = -8.18, P < .001). Mean blood glucose level after implementation was 148 mg/dL. The incidence of hypoglycemia, 2.09% before and 0.22% after the intervention, was significantly reduced ( $${\hbox{ \chi }}_{1}^{2}$$ [n = 29] = 13.9, P < .001). The percentage of blood glucose levels less than 180 mg/dL was 88.30%.

CONCLUSIONS: Increasing nurses' knowledge of glycemic control and implementing an insulin infusion protocol targeting moderate glycemic control were effective for treating acute hyperglycemia following cardiac surgery with decreased incidence of hypoglycemia.