A New Vital Sign?
Realizing the Benefits of Glycemic Control
The work of Dr. Anthony Furnary (1997) and the work of Dr. Greet Van den Berghe (2001) established glycemic control as a key concern for the management of critically ill patients. Dr. Van den Berghe’s seminal study demonstrated that tight glycemic control, using intensive IV insulin therapy, improved patient outcomes in the surgical intensive care unit (ICU) as follows:
- a 46% reduction in the incidence of sepsis
- a 41% reduction in acute renal failure
- a 50% reduction in the need for transfusions
- an overall 34% reduction in mortality1
Over the past seven years, over 400 studies have expanded the interest and clinical utility of glycemic control to include trauma, burn, high risk pregnancy, medical ICU and general floor populations. Blood glucose is now often referred to as an evolving “vital sign” for critical care.
Despite the remarkable outcomes demonstrated by Van den Berghe and now others, many institutions have experienced difficulty in implementing an effective glycemic control program. Most recently, this was demonstrated in the NICE-SUGAR study, a large randomized control trial of over 6,000 patients.2 While this study confirmed the benefits of glucose control in the 140-180 mg/dL range, it concluded that it is not safe to target the 80-110 mg/dL range in the medical ICU using current technologies and clinical protocols.
The challenges that prevent the safe, effective implementation of glycemic control include:
- 1)Measuring glucose with sufficient frequency to effectively administer IV insulin. Insulin is a fast acting agent and poses a significant risk to the patient if over titrated (i.e. hypoglycemia). Current glycemic management protocols call for measurement as often as every 20 minutes,3 but practical considerations often limit measurements to once every 1 hour at best and more frequently every 2-4 hours.
- 2)Inaccurate glucose results when measured with point-of-care glucometers. All leading glucometers are sensitive to hematocrit, leading to significantly aberrant results in anemic or hypovolemic patients.4 These systems may also be sensitive to interference from medications such as maltose or ascorbic acid.
- 3)Significant incremental workload for an already stretched nursing staff. It has been estimated that an incremental 10% is added to the workload of an ICU nurse to effectively implement the required hourly finger sticks.5
1. Van den Berghe G, et al. Intensive Insulin Therapy in Critically Ill Patients. N Engl J Med. 2001;345(19):1359―67.
2. Finfer S, et al. Intensive versus conventional glucose control in critically ill patients. N Engl J Med. 2009;360(13):1283-973. Wilson M, et al. Intensive Insulin Therapy in Critical Care: A review of 12 protocols. Diabetes Care. 2007;30(4):1005-1011.4. Karon BS, et al. Evaluation of the Impact of Hematocrit and Other Interference on the Accuracy of Hospital-Based Glucose Meters. Diabetes Technol Ther. 2008;10(2):111―120.
5. Aragon D. Evaluation of nursing work effort and perceptions about blood glucose testing in tight glycemic control. Am J Crit Care. 2006;15(4):370―7.