Critically evaluate the role of glucose control in the critically ill.

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College Answer

Routine ICU management includes the control of glucose to avoid the potential complications of hypoglycemia (arrhythmias, cardiac events, neurological deficits) and hyperglycemia (especially infections, eg.   documented using restrospective controls). Traditional goals have varied, but have in general been fairly broad (eg. glucose < 10-15 mmol/L).  Prospective randomised trails to guide therapy have been lacking until the last decade.

The potential role for tight glucose control in critically ill patients has been suggested in two main patient groups: acute myocardial infarction in diabetics, and the surgical ICU.

The DIGAMI study demonstrated that an insulin-glucose infusion followed by a multidose insulin regimen improved one year mortality in diabetic patients with acute myocardial infarction (Malmberg JACC 1995).

Much more interest, and significant debate, was generated by the study by Van den Berghe (NEJM 2001).   It demonstrated in a surgical intensive care population (enrolling 1548 patients) that tight glucose control using intensive insulin therapy reduced mortality during intensive care from 8.0 percent with conventional treatment (10 – 11.1 mmol/L) to 4.6 percent(4.5 - 6.5mmol/L)  (NNT = 29; P<0.04, with adjustment for sequential analyses) and “also reduced overall in-hospital mortality by 34 percent, bloodstream infections by 46 percent, acute renal failure requiring dialysis or hemofiltration by 41 percent, the median number of red-cell transfusions by 50 percent, and critical-illness polyneuropathy by 44 percent, and patients receiving intensive therapy were less likely to require prolonged mechanical ventilation and intensive care”.  This was apparently due to glucose control and not insulin dose, but the study could not properly blind the treating physicians, and there are problems in extrapolating this to the general Intensive care population, and further studies are underway.

Discussion

This question closely resembles Question 24 from the second paper of 2006. Essentially, it asks one to discuss the various studies which had (recently for 2006) been published to guide the management of sugars in the ICU. During this dark age, there was the belief that strict control over BSL had some sort of positive influence on the survival of ICU patients. The current strategies for BSL control in critical illness are discussed elsewhere.