This protocol provides adequate BG control within the clinically acceptable range of 80-199 mg/dL but not within the narrower range of 140-180 mg/dL, with a low incidence of hypoglycemia. Risk factors for hypoglycemia and barriers to protocol adherence in the cardiac surgery population should be elucidated.

Learning Objectives: SCCM recommends maintaining blood glucose (BG) less than 150 mg/dL and absolutely less than 180 mg/dL in most critically ill patients, and less than 150 mg/dL in cardiac surgery patients. The Joint Commission Surgical Care Improvement Project (SCIP) has core measures to ensure BG control in cardiac surgery patients. The purpose of this study was to compare adherence to a nurse-driven insulin infusion protocol (IIP) designed to maintain BG 140-180 mg/ dL in patients with hypoglycemia vs controls and to compare the proportion of hypoglycemic events across all units. Methods: This was a case-control study using a database with orders for the IIP from Jan 2012 -May 2013. BG values were collected for the first 72 hours after protocol initiation. Forty controls were identified by random sampling and patients with at least one episode of hypoglycemia (BG < 70 mg/dL) were included as cases. Cases and controls were assessed for excursions from the protocol, defined as an action not indicated by the IIP. An aggressive excursion was defined as a higher insulin dose than indicated or > 2 hours between BG checks. Results: Twenty-one cases and 40 controls were included. The mean (SD) excursions per 100 hours was 39.8 (20) in cases vs 23.5 (17.5) in controls (p=0.002). Sixty-one percent of hypoglycemic events followed an aggressive excursion. The CVSICU accounted for 13 (33%) of the random control patients and 15 (71%) of the hypoglycemic patients. The mean IIP excursions in the CVSICU was 42.8 (15) per 100 hours vs 18.0 (16.3) in other units (OR 5.2, p<0.001). The proportion of aggressive excursions was higher in the CVSICU (0.77 vs 0.53, p=0.004). Conclusions: There are more excursions from the IIP in patients with hypoglycemia compared to controls. The majority of the hypoglycemic events occurred in the CVSICU. There is a higher excursion rate and a higher proportion of aggressive excursions in the CVSICU compared to other units. Further studies are needed to determine if this is due to perceived need to meet SCIP measures or if there are risk factors for hypoglycemia in cardiac surgery patients.

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