Glycemic Control, Cardiac Surgery, and Infection

William R. Jarvis, MD


November 19, 2012

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Hi. This is Dr. William Jarvis, Medscape Infectious Disease expert advisor and President of Jason and Jarvis Associates.

Glycemic control after cardiac surgery has been somewhat controversial. Congenital heart defects are the most common birth defect. Approximately 20,000 pediatric cardiothoracic surgery procedures are performed annually in the United States. Postoperative morbidity and mortality are relatively high. Tight glucose control has been hypothesized as a potential mode for preventing or reducing morbidity and mortality. The incidence of hyperglycemia (≥ 126 mg/dL) has been reported to be as high as 90% in some studies.

In 2009, Vlasselaers and colleagues[1] performed a study in a pediatric intensive care unit in which most patients were post-cardiac surgery. They showed that normalizing glucose postoperatively can reduce mortality from 6% to 3%, shorten length of stay, and reduce overall morbidity. Now we have a study published by Agus and colleagues[2] involving all cardiac surgery patients undergoing cardiopulmonary bypass between September 2006 and May 2012 at 2 centers in the United States.

Their aim was to achieve a blood glucose of 80-110 mg/dL. They used a subcutaneous glucose monitor and an explicit insulin dosing algorithm. They enrolled 989 patients, 9 of whom were excluded, for a total of 980 children up to 3 years of age. These were all patients admitted in the pediatric intensive care unit following cardiac surgery involving cardiopulmonary bypass. A total of 24 healthcare-associated infections occurred in both groups, with no difference between groups (8.6 vs 9.9 infections per 1000 patient days).

So, although they normalized glucose more rapidly (6 hours vs 16 hours) postoperatively, and normoglycemia was maintained for a greater proportion of critical illness phase (50% vs 33%), they still were unable to achieve a significant reduction in healthcare-associated infections. This study shows that a normalization of blood glucose postoperatively in pediatric cardiac surgery patients in the intensive care unit has no impact on postoperative morbidity or mortality. Tight glucose control can raise the risk for hypoglycemia (which was actually rare in this study at 3%) and doesn't produce any benefit for these post-cardiac surgery patients.

Thank you. Until next time, I'm Dr. William Jarvis of Jason and Jarvis Associates.