Comparison of Insulin Infusion Protocols Targeting 110–140 mg/dL in Patients After Cardiac Surgery

Abstract

Background:

Continuous intravenous insulin infusion (CII) following coronary artery bypass graft (CABG) surgery reduces postoperative complications and hospitalization duration. Because of limited data evaluating outcomes of CII with revised glycemic targets (110–140 mg/dL) in cardiac surgery, this study compared efficacy and safety of two different CII protocols having revised targets.

Subjects and Methods:

This is a retrospective study comparing two different protocols between August 2009 and March 2010. Protocol 1 consists of four algorithms, and Protocol 2 is a table to adjust CII. Blood glucose (BG) and CII rates were recorded for 48 h postoperatively or CII discontinuation. Efficacy was defined by the percentage of BG values in the target range, and safety was defined by the percentage of BG values<40 and 40–69 mg/dL.

Results:

Protocol 1 (n=117) patients were older (65 vs. 61 years; P=0.006) and had more CABG and fewer valve procedures compared with Protocol 2 (n=130). There were no differences in baseline BG level (149±40.6 vs. 151±38.1 mg/dL), body mass index (30±6.3 vs. 30±6.4 kg/m²), hematocrit (28% vs. 28%), percentage of diabetes patients (32% vs. 31%), percentage of patients with glomerular filtration rate of <30 mL/min (5% vs. 6%), CII duration (42 [9–48] vs. 40 [14–48] h), total insulin units received (99 [15–376] vs. 114 [12–457]), hourly insulin rate (median of average rate [range], 2.59 [0–21) vs. 2.96 [0–25] units/h), percentage of BG values 110–140 mg/dL, <40 mg/dL, 40–69 mg/dL, and >180 mg/dL, and BG coefficient of variation (21±6.5 vs. 21±6.1). Shorter time to goal (3.32 [0.22–19.35] vs. 5.03 [0.92–19.80] h; P=0.018) and lower mean BG level (127±12.2 vs. 133±12.1 mg/dL; P<0.001) were noted with Protocol 1.

Discussion:

CII protocols targeting 110–140 mg/dL were effective in achieving revised targets with low hypoglycemia. Despite differences in mean BG level and time to target, each hospital continued using its existing protocols and identified areas for improvement.