To Örebro University

Objective: Studies have shown a higher risk of postoperative complications in diabetic and obese patients. An increased intraperitoneal lactate/pyruvate ratio as measured by microdialysis has been reported before postoperative complications have been discovered. It is not known whether diabetes or obesity have any influence on the intraperitoneal metabolism (lactate/pyruvate ratio, glucose, glycerol) in relation to major abdominal surgery. The aim of this study was to investigate the postoperative intraperitoneal and subcutaneous carbohydrate and fat metabolism as measured by microdialysis in obese and diabetic patients after major abdominal surgery without postoperative complications.

Material and methods: Seven obese patients (body mass index > 30 kg/m(2)) and six diabetic but non-obese patients were studied up to 48 h after major abdominal surgery and were compared with 31 non-diabetic, non-obese patients, all without complications. Microdialysis was performed to measure glucose, lactate, pyruvate and glycerol intraperitoneally and subcutaneously. The lactate/pyruvate ratio was calculated.

Results: The lactate/pyruvate ratio did not differ between the groups. In the diabetic patients, glucose levels were higher intraperitoneally at both Days 1 and 2 compared to controls. Higher glycerol levels were found subcutaneously in obese patients at Day 2. CONCLUSIONS: The lactate/pyruvate ratio does not increase intraperitoneally after non-complicated major abdominal surgery in diabetic and obese patients. Obese patients have increased release of free fatty acids and glycerol subcutaneously, while diabetic patients show higher glucose levels intraperitoneally than controls.

Objective: We have previously presented microdialysis findings of early intraperitoneal (ip) metabolic disturbances, mainly an increased lactate/pyruvate (l/p) ratio, in surgical patients developing postoperative complications. The aim of the present study was to investigate ip glycerol and l/p ratio after major surgery with and without complications.

Material and methods :Sixty patients were followed with microdialysis for 48 h after major abdominal surgery, 44 patients without postoperative complications and 16 patients with major surgical complications. Intraperitoneal and subcutaneous (sc) measurements of glycerol, lactate, pyruvate and glucose were performed, and the l/p ratio was calculated.

Results: Intraperitoneal glycerol was significantly lower in the complication group compared with the control group (64 vs. 94.6 μM; p = 0.0015), while the ip l/p ratio was significantly higher in the complication group compared with the control group (13.7 vs. 11.1; p = 0.0073).

Conclusions: In this study, ip glycerol levels were lower and ip l/p ratio was higher in the immediate postoperative period in a group of patients with complications. These results might indicate early ip disturbances in fat and carbohydrate metabolism in patients who later developed symptoms of postoperative major complications.

Objectives: This study aims to evaluate intra-peritoneal (ip) microdialysis after endovascular aortic repair (EVAR) of ruptured abdominal aortic aneurysm (rAAA) in patients developing intra-abdominal hypertension (IAH), requiring abdominal decompression.

Design: Prospective study.

Material and methods: A total of 16 patients with rAAA treated with an emergency EVAR were followed up hourly for intra-abdominal pressure (IAP), urine production and ip lactate, pyruvate, glycerol and glucose by microdialysis, analysed only at the end of the study. Abdominal decompression was performed on clinical criteria, and decompressed (D) and non-decompressed (ND) patients were compared.

Results: The ip lactate/pyruvate (l/p) ratio was higher in the D group than in the ND group during the first five postoperative hours (mean 20 vs. 12), p = 0.005 and at 1 h prior to decompression compared to the fifth hour in the ND group (24 vs. 13), p = 0.016. Glycerol levels were higher in the D group during the first postoperative hours (mean 274.6 vs. 121.7 mu M), p = 0.022. The IAP was higher only at 1 h prior to decompression in the D group compared to the ND group at the fifth hour (mean 19 vs. 14 mmHg).

Conclusions: lp l/p ratio and glycerol levels are elevated immediately postoperatively in patients developing IAH leading to organ failure and subsequent abdominal decompression.

Objective: To investigate the effect of aortic supra-celiac balloon occlusion (ABO) and superior mesenteric artery (SMA) occlusion on abdominal visceral metabolism in an animal model by using intraperitoneal microdialysis (IPM) and laser Doppler flowmetry. Design: Prospective study in pigs

Material and methods: Nine pigs were subjected to ABO and seven animals were subjected to SMA occlusion for one hour followed by three hours of reperfusion. Seven animals served as controls. Hemodynamic data, arterial blood samples, urinary output and intestinal mucosal blood flow (IBF) were followed hourly. Intraperitoneal (i.p) glucose, glycerol, lactate and pyruvate concentrations and lactate-pyruvate (l/p) ratio were measured by IPM.

Results: Compared to baseline, ABO reduced IBF by 76% and decreased urinary output. SMA occlusion reduced IBF by 75% without affecting urinary output. ABO increased the i.p l/p ratio from 18 at baseline, peaking at 46 in early reperfusion. SMA occlusion and reperfusion tended to increase the i.p l/p ratio, peaking at 36 in early reperfusion. ABO increased the i.p glycerol concentration from 87 μM at baseline to 579 μM after three hours of reperfusion. SMA occlusion and reperfusion increased the i.p glycerol concentration but to a lesser degree.

Conclusions: Supra-celiac ABO caused severe hemodynamic, renal and systemic metabolic disturbances compared to SMA occlusion, most likely due to the more extensive ischemiareperfusion injury. The intra-abdominal metabolism, measured by microdialysis, was affected both by ABO and SMA occlusion but the most severe disturbances were caused by ABO. The i.p l/p ratios and the glycerol concentrations increased during ischemia and reperfusion and may serve as markers of these events and indicate anaerobic metabolism and cell damage respectively.