Blood Glucose Control in the ICU Setting



Intensive insulin therapy is extensively used to lower blood glucose concentrations in critically ill patients hospitalized within the intensive care unit. The discovery by the NICE-SUGAR study investigators that tight glucose control in this setting might actually increase mortality has generated considerable discussion about the wisdom of this approach.

Compelling evidence from a 2001 publication showed that intensive insulin therapy to maintain blood glucose concentrations at 4.4–6.1 mmol/l reduced the morbidity and mortality of critically ill patients hospitalized in surgical intensive care units (ICUs).

Hyperglycemia commonly ensues, even in patients who do not have pre-existing diabetes mellitus. A study was carried out and analysis of data revealed that strict maintenance of blood glucose concentrations ≤6.1 mmol/l (blood glucose target 4.4-6.1 mmol/l) reduced mortality in the ICU by 42%.

These dramatic findings prompted numerous hospitals to institute tight glucose control protocols, which quickly became the 'standard of care', even in medical and surgical patients outside the ICU. The latter approach is based, in part, on observational studies that demonstrated poor clinical outcomes in non-ICU inpatients with hyperglycemia.

The multinational NICE-SUGAR trial (2008) was designed to test the hypothesis that intensive glucose control reduces mortality at 90 days. The target glucose ranges were 4.5–6.0 mmol/l and ≤ 10.0 mmol/l in the intensive and conventional treatment groups, respectively.

Unexpectedly, mortality in the intensive-control group was significantly higher than that in the conventional-control group (27.5% versus 24.9%). Severe hypoglycemia (defined as a blood glucose concentration ≤ 2.2 mmol/l) was also higher in the intensive group than in the conventional group (6.8% versus 0.5%). Of note, the excess deaths in the intensive-treatment group were predominantly cardiovascular, which is consistent with evidence from other studies that severe hypoglycemia might be associated with adverse cardiovascular events.

Thus, on the basis of the recent available evidences, insulin infusion should be used to control hyperglycemia in the majority of critically ill patients in the ICU setting, with a starting threshold of no higher than 10.0 mmol/l. Once IV insulin therapy has been initiated, glucose level should be maintained between 6.0 and 10.0 mmol/l and greater benefit may be realized at the lower end of this range. Glucose control needs to be implemented safely to avoid insulin-induced hypoglycemia.


3. Management Protocols in ICU, Kementerian Kesihatan Malaysia (August 2012)

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