The importance of intensive insulin therapy in critical illness has been widey accepted since Van den Berghe (2001) demonstrated that maintaining blood glucose ≤ 110 mg/dl reduced morbidity and mortality in SICU patients. We assessed glycemic control achieved with a simplified insulin infusion protocol using a Continuous Glucose Monitoring System (CGMS, Medtronic MiniMed) in an MICU.
Therapy was initiated with regular insulin bolus followed by continuous insulin infusion titrated according to a standard protocol with a target glucose of 80 - 110 mg/dl. Traditional monitoring included morning laboratory blood glucose measurements plus glucometer measurements every 2 - 4 hours. The CGMS sampled interstitial fluid, recording glucose values every 5 minutes for 72 hours. Data analysis focused on the number of excursions and percentage of time above or below the target range. Factors contributing to periods of hypo- and hyper-glycemia were identified.
Fifty patients were studied, yielding ∼35,000 CGMS glucose readings. Overall, only 50% of values were in the target range. Patients could be stratified retrospectively into those with predominantly tight control and those with poor control. Factors contributing to poor glycemic control included elevated blood glucose on admission, corticosteroids and antibiotic therapy, gastroparesis, prior history of diabetes, interruption of enteral tube feeding, bacteremia, and multiple organ involvement as reflected by elevated serum creatinine and liver enzyme studies.
Tight glycemic control in MICU patients is desirable but difficult to achieve in clinical practice. We evaluated the implementation of a simplified insulin infusion protocol feasible for general use. Retrospective analysis of CGMS data identified patient characteristics associated with poor control. These data may permit the prospective identification of patients requiring more intensive monitoring, and will contribute to the development of more effective infusion strategies specifically targeted to this population.
Continuous glucose monitoring data is helpful in achieving tight glycemic control in MICU patients.
M.S. Farmer, None.