The effect of glucose control in liver surgery on glucose kinetics and insulin resistance.

BACKGROUND & AIMS: Clinical outcome is negatively correlated to postoperative insulin resistance and hyperglycemia. The magnitude of insulin resistance can be modulated by glucose control, preoperative nutrition, adequate pain management and minimal invasive surgery. Effects of glucose control on perioperative glucose kinetics in liver surgery is less studied. METHODS: 18 patients scheduled for open hepatectomy were studied per protocol in this prospective, randomized study. In the treatment group (n = 9), insulin was administered intravenously to keep arterial blood glucose between 6 and 8 mmol/l during surgery. The control group (n = 9) received insulin if blood glucose >11.5 mmol/l. Insulin sensitivity was measured by an insulin clamp on the day before surgery and immediately postoperatively. Glucose kinetics were assessed during the clamp and surgery. RESULTS: Mean intraoperative glucose was 7.0 mM (SD 0.7) vs 9.1 mM (SD 1.9) in the insulin and control group respectively (p < 0.001; ANOVA). Insulin sensitivity decreased in both groups but significantly (p = 0.03, ANOVA) more in the control group (M value: 4.6 (4.4-6.8) to 2.1 (1.2-2.6) and 4.6 (4.1-5.0) to 0.6 (0.1-1.8) mg/kg/min in the treatment and control group respectively). Endogenous glucose production (EGP) increased and glucose disposal (WGD) decreased significantly between the pre- and post-operative clamps in both groups, with no significant difference between the groups. Intraoperative kinetics demonstrated that glucose control decreased EGP (p = 0.02) while WGD remained unchanged (p = 0.67). CONCLUSION: Glucose control reduces postoperative insulin resistance in liver surgery. EGP increases and WGD is diminished immediately postoperatively. Insulin seems to modulate both reactions, but mostly the WGD is affected. Intraoperative EGP decreased while WGD remained unaltered. REGISTRATION NUMBER OF CLINICAL TRIAL: ANZCTR 12614000278639.

Continuous on-line glucose measurement by microdialysis in a central vein. A pilot study.

INTRODUCTION: Tight glucose control in the ICU has been proven difficult with an increased risk for hypoglycaemic episodes. Also the variability of glucose may have an impact on morbidity. An accurate and feasible on-line/continuous measurement is therefore desired. In this study a central vein catheter with a microdialysis membrane in combination with an on-line analyzer for continuous monitoring of circulating glucose and lactate by the central route was tested. METHODS: A total of 10 patients scheduled for major upper abdominal surgery were included in this observational prospective study at a university hospital. The patients received an extra central venous catheter with a microdialysis membrane placed in the right jugular vein. Continuous microdialysis measurement proceeded for 20 hours and on-line values were recorded every minute. Reference arterial plasma glucose and blood lactate samples were collected every hour. RESULTS: Mean microdialysis-glucose during measurements was 9.8 ± 2.4 mmol/l.No statistical difference in the readings was seen using a single calibration compared to eighth hour calibration (P =0.09; t-test). There was a close agreement between the continuous reading and the reference plasma glucose values with an absolute difference of 0.6+0.8 mmol, or 6.8+9.3% and measurements showed high correlation to plasma readings (r = 0.92). The limit of agreement was 23.0%(1.94 mmol/l) compared to arterial plasma values with a line of equality close to zero.However, in a Clarke-Error Grid 93.3% of the values are in the A-area,and the remaining part in the B-area.Mean microdialysis-lactate was 1.3 ± 1.1 mmol/l. The measurements showed high correlation to the blood readings (r = 0.93). CONCLUSION: Continuous on-line microdialysis glucose measurement in a central vein is a potential useful technique for continuous glucose monitoring in critically ill patients, but more improvements and testing are needed.

The effect of perioperative glucose control on postoperative insulin resistance.

BACKGROUND & AIMS: Postoperative insulin resistance and the consequent hyperglycemia affects clinical outcome. Insulin sensitivity may be modulated by preoperative nutrition, adequate pain management and minimal invasive surgery. This study aims to disclose the impact of perioperative glucose control on postoperative insulin resistance. METHODS: Twenty patients scheduled for elective open hepatectomy were enrolled in this prospective, randomized study. In the treatment group (n = 9) insulin was administered intravenously to keep blood glucose between 6 and 8 mmol/l during surgery. The control group (n = 8) received insulin if blood glucose >14 mmol/l. Insulin sensitivity was measured by a hyperinsulinemic normoglycemic clamp (0.8 mU/kg/min), performed on all patients both on the day before surgery and immediately postoperatively. Plasma cortisol, insulin and C-peptide were measured. RESULTS: There was a significant difference in mean glucose value during surgery. In the control group 8.8 mmol/l (SD 1.5) vs. 6.9 mmol/l (SD 0.4) in the treated group, p = 0.003. In the control group insulin sensitivity decreased to 21.9% ± 16.2% of the preoperative value and in the insulin treated group to 46.8 ± 15.5%, p < 0.005. Insulin levels were significantly higher in the treatment group as well as consequently lower C-peptide levels. CONCLUSIONS: This trial revealed a significant difference in postoperative insulin resistance in the group treated with insulin during surgery.