Tight blood glucose control decreases surgical wound infection in the cardiac surgical patient population in the ICU

Introduction

Tight blood glucose control (TBGC) results in a decrease in the infection rate in critically ill patients. In 2002 a retrospective analysis of 38 postoperative patients in our cardiac surgical ICU revealed that most of the patients had a high serum glucose level upon arrival and remained so throughout their stay irrespective of their diabetes status. Additionally it was noted that the number of infections exceeded the international accepted rate.

Methods

Based on those findings, we initiated a prospective observational study implementing a continuous insulin intravenous infusion protocol as recommended internationally in our patients, both diabetic and nondiabetic, to achieve a blood glucose level (BGL) between 4 and 8 mmol/l. Our sample study population included 116 patients, mean age 54 (± 17.9) years, 65 (56%) were males, 62 (53%) received coronary artery bypass grafting and 46 (40%) were diabetic. Initially there was resistance to implement this protocol and compliance was poor. We therefore embarked on a nursing and physician education program for more than 1 year. We initiated a new prospective study in 2006–2007. The study included 270 patients, mean age 52 years (± 15.8), 155 (57%) were males, 136 (50%) received coronary artery bypass grafting and 97 (36%) were diabetic.

Results

The demographics of the study patients were similar. The mean admission BGL, highest BGL, lowest BGL and discharge BGL for 2003 and 2006–2007 were 8.1/13/7.9/11 mmol/l and 7.8/12.8/4.6/8.3 mmol/l, respectively. A comparison of wound infection rates before and after full implementation of TBGC showed a decrease in the rate from 7.25% in 2002 to 3.3% in 2007 (P = 0.02). The blood stream infection rate, however, did not showed any statistical significant change, 2% in 2003 versus 1.9% in 2007 (P = 0.4).

Conclusion

Our study showed that implementing TBGC in cardiac surgical patients decreases surgical wound infection but does not change significantly the bloodstream infection.