Effect of Tight Glycaemic Control on Post Operative Infection in Diabetics with raised Glycosylated Haemoglobin

Kamal Kumar, - (2008) Effect of Tight Glycaemic Control on Post Operative Infection in Diabetics with raised Glycosylated Haemoglobin. Masters thesis, Christian Medical College, Vellore.


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INTRODUCTION: Patients with diabetes mellitus have been shown to have a higher incidence of perioperative morbidity and mortality compared to those without diabetes, which is attributed to hyperglycaemia. There is substantial evidence to suggest that mean blood glucose levels >200-230 mg.dL-1 is associated with increased risk of infection. The widely followed practice is to maintain the plasma glucose below 200mg.dL-1, in the post-operative period. However, has been shown that ‘tight’ control of blood sugar at 80-110 mg.dL-1 reduces the morbidity and mortality further, but this was achieved in an intensive care unit setting, and required frequent monitoring of blood sugar level to avoid hypoglycemia. Some authors have suggested that the effect of chronic hyperglycaemia may also contribute to post-operative morbidity. The level of glycosylated haemoglobin (HbA1c) reflects the control of blood glucose in the previous 8-12 weeks. A clinical audit of 490 diabetics undergoing elective surgery demonstrated that those with HbA1c greater than 7% had a higher incidence of surgical site infection. This study is an effort to answer the question, whether maintaining a tighter control of blood sugar in the immediate post-operative period, in patients with HbA1c > 7%, reduces post-operative infection. AIM AND OBJECTIVES: To study the effect of tight glycaemic control on posy-operative infection in diabetics with raised glycosylated haemoglobin. 1. To measure the incidence of post-operative infection in diabetics and to analyze its correlation with the level of glycosylated haemoglobin. (clinical audit). 2. To compare the effect of restricting the post-operative blood glucose < 140 mg.dL-1 to the existing practice of maintaining it < 200 mg.dL-1 on post-operative infection, in diabetics with glycosylated haemoglobin more than 7%. (interventional clinical trial) Patients and Methodology: Approval was obtained from the institutional research and ethical committee before starting the clinical trial. All diabetic patients, with glycosylated haemoglobin (HbA1c) of more than 7%, scheduled for elective surgery, were eligible to be enrolled in this study. Patients with preoperative infection were excluded. These patients were explained about the study by the anaesthesiologist the evening before the surgery and a written consent was obtained from the volunteers. All medications, including oral hypoglycemic drugs (except for metformin) were administered the evening before the surgery. The patients were fasted for six hours prior to surgery and allowed clear fluids up to two hours before surgery. On the day of the surgery, oral hypoglycaemic drugs and insulin were omitted. Blood glucose was measured just before induction of anaesthesia. All the patients received a standard general anaesthetic technique using midazolam, fentanyl, thiopentone, and vecuronium for induction, and maintained with morphine, oxygen, air and isoflurane. SAMPLE SIZE: The Clinical Audit demonstrated that the incidence of post-operative wound infection in diabetic patients with HbA1c level > 7% was 30% (P1). The hypothesis of the clinical trial was to show if maintaining the post-operative glucose level below 140 mg.dL-1 would reduce wound infection to less than 5%. Statistical Analysis: The basic structure of the analysis was a comparison of two groups of patients undergoing major elective surgery with high glycosylated haemoglobin. The major outcome event was the blood glucose control during the post-operative period and the development of surgical wound infection. Using the summary statistic approach, the average value of the blood glucose was calculated for each patient. Independent test was performed over the summary statistic to find the difference in mean. Base line and postoperative outcome variables were compared with the use of Pearson’s chi-square test. The analysis was done using ‘SPSS for Windows’ version11 software. RESULTS: Fifty diabetic patients with glycosylated haemoglobin greater than 7%, scheduled for elective surgery, were consented for the study. The preoperative and intra-operative management of all the patients were similar. At the end of the surgery, they were randomly allocated into one of the two groups to decide the glycaemic control during the post-operative period. The plasma glucose level of those in the Study Group was aimed below 140 mg.dL-1, while for those in the Control Group was aimed below 200 mg.dL-1, as is the standard practice in this institution. All the patients were managed in the general ward. CONCLUSION: Diabetics with glycosylated haemoglobin more than 7 % have a high incidence of surgical site infection and other complications in the post-operative period which can be reduced by maintaining a mean glucose level below 140 mg.dL-1 during the initial 3 – 5 post-operative days.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Tight Glycaemic Control ; Post Operative Infection ; Diabetics ; Glycosylated Haemoglobin.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 30 Apr 2018 02:53
Last Modified: 30 Apr 2018 02:53
URI: http://repository-tnmgrmu.ac.in/id/eprint/7314

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