What is IV insulin therapy?

Updated: Nov 06, 2018
  • Author: Guy W Soo Hoo, MD, MPH; Chief Editor: George T Griffing, MD  more...
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Patients with hyperglycemia in the ICU have increased morbidity and mortality. Hyperglycemia is associated with immune dysfunction, increased systemic inflammation, and vascular insufficiency. Elevated blood glucose levels have been shown to worsen outcomes in medical patients who are in the ICU for more than 3 days. Hyperglycemia may result from stress, infection, steroid therapy, decreased physical activity, discontinuation of outpatient regimens, and nutrition. [1]

Improved control of hyperglycemia improves patient outcomes, but clinical confirmation of this thesis has proven elusive. Significant interest was generated by initial single-center results that have not been replicated in multisite studies. In 2001, a randomized controlled study in a surgical ICU demonstrated a decrease in mortality from 8% to 4.6% in patients with intensive continuous intravenous insulin therapy. [2] The author repeated the protocol in a study of 1200 patients in a medical ICU. [3] The conventional treatment group was treated to maintain a blood glucose level between 180-200 mg/dL, whereas the intensive treatment group was treated to maintain a blood glucose level between 80-110 mg/dL. Mortality was not significantly reduced by intensive insulin therapy and was actually higher in patients in the intensive treatment group who were in the ICU for less than 3 days. In patients who were in the ICU for longer than 3 days, the intensive treatment group did demonstrate reduced morbidityfrom decreased kidney injury, earlier weaning from mechanical ventilation, and earlier discharge from the medical ICU and hospital. Hypoglycemia occurred more often in the intensive treatment group than the conventional treatment group. In addition, an experienced physician was actively involved in administration of the protocol, a luxury not uniformly available to many hospitals and a variable that limited the ability to generalize their results to other centers.

However, the results were encouraging and represented a marked improvement in several areas, stimulating great interest in tight glucose control with intravenous insulin, which, in turn, stimulated the development of a multitude of intravenous insulin protocols. However, the protocols widely varied and little uniformity was observed among medical centers. Questions persisted as to the optimal protocol and targets and the need for a unified, uniform approach to control of hyperglycemia.

The NICE SUGAR study published in 2009 was a large, international, randomized trial intended to address the shortcomings of previous studies. [4] The study enrolled 6104 patients who were either assigned to tight glucose control with a target of 81-108 mg/dL or conventional glucose control with a target of 180 mg/dL or less. At the end of the 90-day study period, mortality was 27.5% of patients in the tight glucose control group and 24.9% of patients in the conventional control group, with an odds ratio of 1.14 for death with tight glucose control. No significant difference in the median length of stay in the ICU or hospital was noted. Severe hypoglycemia was significantly more common with tight glucose control. This experience dampened the routine use of intravenous insulin therapy in critically ill patients; however, continuous intravenous insulin therapy still has a role in the management of critically ill patients.

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