Evaluation of a Nurse-Managed Insulin Infusion Protocol

Abstract

BACKGROUND: The purpose of this study was to evaluate the performance of an insulin infusion protocol targeting a blood glucose (BG) level of 140-180 mg/dL and to characterize protocol adherence. MATERIALS AND METHODS: This was a retrospective observational cohort study including patients for whom the protocol was ordered from January 2012 to May 2013. Performance metrics were assessed in all patients and in patients with an initial BG level of ≥200 mg/dL. Protocol adherence was assessed in a random subset of 50 patients without hypoglycemia and in all hypoglycemic patients. RESULTS: In patients with an initial BG level of ≥200 mg/dL, the mean time to goal was 7.1 h. The rate of decline of BG level in the first 6 h was 16.4 mg/dL/h. Mean BG level was 167 mg/dL, with 43.9% of BG values within goal and 80.3% between 80 and 199 mg/dL. The rate of hypoglycemic events was 0.14 per 100 h. The mean protocol violation rate was higher in patients with hypoglycemia compared with those without (39.8 vs. 23.5 per 100 h, P = 0.002), and 60.7% of hypoglycemic events were attributable to protocol violations. The protocol violation rate (42.8 vs. 17.6 per 100 h; P < 0.001) and the odds of hypoglycemia (odds ratio = 5.2; 95% confidence interval, 1.6, 16.5) were higher in the cardiac surgery patients compared with other patients. CONCLUSIONS: 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.