Intensive insulin therapy in the intensive care unit: assessment by continuous glucose monitoring.

Abstract

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). 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 II 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. 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 >110 mg/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 (beta = 0.73, P < 0.0001). Diabetic state (beta = 0.47, P < 0.0001), septic shock (beta = 0.22, P = 0.045), sequential organ failure assessment score (beta = 0.40, P = 0.001), and use of corticoids (beta = 0.28, P = 0.014) and inotropics (beta = -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. 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.