A sweet debate: glycemic control in the intensive care unit

The optimal blood glucose level for critically ill adult patients

BACKGROUND

Glycaemic control is recognized as one of the important aspects in managing critically ill patients. Both hyperglycaemia and hypoglycaemia independently increase the risk of patient mortality. Hence, the identification of optimal glycaemic control is of paramount importance in the management of critically ill patients.

AIMS AND OBJECTIVES

The aim of this literature review is to examine the current status of glycaemic control in critically ill adult patients. This literature review will focus on randomized controlled trials comparing intensive insulin therapy to conventional insulin therapy, with an objective to identify optimal blood glucose level targets for critically ill adult patients.

DESIGN AND METHODS

A literature review was conducted to identify large randomized controlled trials for the optimal targeted blood glucose level for critically ill adult patients published since 2000. A total of eight studies fulfilled the selection criteria of this review.

RESULTS

With current human and technology resources, the results of the studies support commencing glycaemic control once the blood glucose level of critically ill patients reaches 10 mmol/L and maintaining this level between 8 mmol/L and 10 mmol/L.

CONCLUSION

This literature review provides a recommendation for targeting the optimal blood glucose level for critically ill patients within moderate blood glucose level target range (8-10 mmol/L). The need for uniformed glucometrics for unbiased reporting and further research for optimal blood glucose target is required, especially in light of new technological advancements in closed-loop insulin delivery and monitoring devices.

RELEVANCE TO CLINICAL PRACTICE

This literature review has revealed a need to call for consensus in the measurement and reporting of glycaemic control using standardized glucometrics.

Hyperglycemia-related mortality in critically ill patients varies with admission diagnosis

OBJECTIVES

Hyperglycemia during critical illness is common and is associated with increased mortality. Intensive insulin therapy has improved outcomes in some, but not all, intervention trials. It is unclear whether the benefits of treatment differ among specific patient populations. The purpose of the study was to determine the association between hyperglycemia and risk- adjusted mortality in critically ill patients and in separate groups stratified by admission diagnosis. A secondary purpose was to determine whether mortality risk from hyperglycemia varies with intensive care unit type, length of stay, or diagnosed diabetes.

DESIGN

Retrospective cohort study.

SETTING

One hundred seventy-three U.S. medical, surgical, and cardiac intensive care units.

PATIENTS

Two hundred fifty-nine thousand and forty admissions from October 2002 to September 2005; unadjusted mortality rate, 11.2%.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A two-level logistic regression model determined the relationship between glycemia and mortality. Age, diagnosis, comorbidities, and laboratory variables were used to calculate a predicted mortality rate, which was then analyzed with mean glucose to determine the association of hyperglycemia with hospital mortality. Hyperglycemia was associated with increased mortality independent of illness severity. Compared with normoglycemic individuals (70-110 mg/dL), adjusted odds of mortality (odds ratio, [95% confidence interval]) for mean glucose 111-145, 146-199, 200-300, and >300 mg/dL was 1.31 (1.26-1.36), 1.82 (1.74-1.90), 2.13 (2.03-2.25), and 2.85 (2.58-3.14), respectively. Furthermore, the adjusted odds of mortality related to hyperglycemia varied with admission diagnosis, demonstrating a clear association in some patients (acute myocardial infarction, arrhythmia, unstable angina, pulmonary embolism) and little or no association in others. Hyperglycemia was associated with increased mortality independent of intensive care unit type, length of stay, and diabetes.

CONCLUSIONS

The association between hyperglycemia and mortality implicates hyperglycemia as a potentially harmful and correctable abnormality in critically ill patients. The finding that hyperglycemia-related risk varied with admission diagnosis suggests differences in the interaction between specific medical conditions and injury from hyperglycemia. The design and interpretation of future trials should consider the primary disease states of patients and the balance of medical conditions in the intensive care unit studied.