Intensive insulin therapy in the intensive care unit - Assessment by continuous glucose monitoring

OBJECTIVE - Hyperglycemia occurs in most critically ill patients. Using continuous glucose monitoring (CGM), we investigated whether intensive insulin therapy based on discontinuous glucose monitoring can achieve normoglycemia (80-110 mg/dl) in a medical intensive care unit (MICU). RESEARCH DESIGN AND METHODS - Fifty adults (men/women 31/19, age 62 +/- 16 years, nondiabetic/diabetic 30/20, intravenous/subcutaneous insulin 22/28, and Acute Physiology and Chronic Health Evaluation 11 score 22 - 7) were prospectively recruited. Forty-eight-hour CGM was performed using a subcutaneous glucose sensor (GlucoDay) and compared with arterial glycemia. Main outcome measures were percent of time in normoglycemia and accuracy/applicability of CGM. RESULTS - During 48-h CGM, glycemia reached target (80-110 mg/dl) in only 22 +/- 18%, was > 140 mg/dl in 39 +/- 27%, and was < 60 mg/dl in 5 +/- 10% of the time. Patients on subcutaneous versus intravenous insulin had more glycemia readings > 110mg/dl(P = 0.016). Glycemia was higher in diabetic patients (170 - 77 vs. 129 35 mg/dl, P = 0.013). BMI was an independent determinant for bad glycemic control (P = 0.73, P < 0.0001). Diabetic state (P = 0.47, P < 0.0001), septic shock (P = 0.22, P = 0.045), sequential organ failure assessment score (P = 0.40, P = 0.001), and use of corticoids (P = 0.28, P = 0.014) and inotropics (P = -0.24, P = 0.035) were independent determinants of insulin dose. GlucoDay values and arterial glycemia correlated well (r = 0.85, P - 0.0001, n = 555 after six-point calibration), with 97% of data falling in regions A and B of error grid analysis. There were no adverse events using GlucoDay. CONCLUSIONS - GlucoDay, a well-tolerated 48-h CGM system, revealed that normoglycemia was only achieved 22% of the time in MICU patients. Further studies should investigate whether application of CGM to titrate insulin therapy can improve patient outcome.