Investigation of hypoglycemia in an intensive care setting

In 2001 a landmark study demonstrated that normalization of blood glucose significantly reduces mortality and morbidity among intensive care patients. Now 5 years on, strict control of blood glucose concentration with insulin therapy is accepted as an imperative of optimal intensive care in many hospitals around the world. 

One of the potential problems of insulin therapy is that blood glucose may fall too low. Since reduced blood glucose (hypoglycemia) is associated with risk of significant morbidity (convulsion, coma) and ultimately death, the issue of hypoglycemia among intensive care patients is of great interest. 

A recent study sought to examine the extent and consequences of hypoglycemia among patients being cared for in a 28-bed intensive care unit where a policy of strict glucose control has been adopted. The authors identified all cases of hypoglycemia (defined as blood glucose <45 mg/dL, <2.5 mmol/L) that had occurred over a 2-year period in this unit. 

A total of 156 patients had suffered 245 episodes of hypoglycemia. These patients represent 6.9 % of all those who had been cared for in the unit during the 2-year study period. In most cases, prompt treatment (withdrawal of insulin and/or administration of IV glucose) ensured that the hypoglycemia was of brief duration (<3 hours between identification of hypoglycemia and return to normal blood glucose concentration).

By comparing the outcome of those who suffered a hypoglycemic episode (cases) with the outcome of matched (control) intensive care patients whose blood glucose remained normal, the authors were able to conclude that hypoglycemia among their intensive care patients was not associated with increased risk of death. 

No cases of hypoglycemia-associated death were reported. Just two cases of possible hypoglycemia-related coma and one case of possible hypoglycemia-related seizure were identified. The results of this study indicate that the brief periods of hypoglycemia that intensive care patients might suffer as a result of an intensive insulin therapeutic regime are not likely to cause them harm.