Surface microdialysis on small bowel serosa in monitoring of ischemia.

BACKGROUND: Ischemic injury of an organ causes metabolic change from aerobic to anaerobic metabolism. It has been shown in experimental studies on the heart and liver that such conversion may be detected by conventional microdialysis probes placed intra-parenchymatously, as well as on organ surfaces, by assaying lactate, pyruvate, glucose, and glycerol in dialysate. We developed a microdialysis probe (S-µD) intended for use solely on organ surfaces. The aim of this study was to assess whether the newly developed S-µD probe could be used for detection and monitoring of small bowel ischemia. METHODS: In anesthetized normoventilated pigs, a control S-µD probe was applied on the jejunal serosa 50 cm downstream from the duodenojejunal junction (DJJ). Starting 100 cm from DJJ, a 100-cm long ischemic segment was created by division of all mesenteric vessels. S-µDs were applied at 2.5, 5, 20, and 50 cm from the starting point of ischemia by serosal sutures. A standard µD probe was placed in the abdominal cavity as a further control. Dialysate was harvested before inducing ischemia and subsequently every 20 min for 4 h. Central venous blood was drawn every hour to monitor systemic lactate, C-reactive protein, and white blood cell count. RESULTS: Microdialysis lactate levels were significantly higher than baseline from 20 min on into protocol time in the ischemic segment and in the control S-µD probe. The peritoneal cavity probe showed no significant elevation. Lactate levels from the ischemic segment reached a plateau at 60 min. Courses of pyruvate, glucose, and glycerol levels were in accordance with transition from an aerobic to anaerobic metabolism in the bowel wall. No statistically significant changes in hemoglobin, white blood cell count, or lactate values in central venous blood were recorded. CONCLUSIONS: Assaying the aforementioned compounds in dialysate, harvested by the newly developed S-µD probe, allowed detection and monitoring of small bowel ischemia from 20 min on following its onset.

Outcome of microdialysis sampling on liver surface and parenchyma.

BACKGROUND: To investigate whether surface microdialysis (µD) sampling in probes covered by a plastic film, as compared to noncovered and to intraparenchymatous probes, would increase the technique's sensitivity for pathophysiologic events occurring in a liver ischemia-reperfusion model. Placement of µD probes in the parenchyma of an organ, as is conventionally done, may cause adverse effects, e.g., bleeding, possibly influencing outcome. METHODS: A transient ischemia-reperfusion model of the liver was used in six anesthetized normoventilated pigs. µD probes were placed in the parenchyma and on the liver surface. Surface probes were either left uncovered or were covered by plastic film. RESULTS: Lactate and glucose levels were significantly higher in plastic film covered probes than in uncovered surface probes throughout the ischemic period. Glycerol levels were significantly higher in plastic film covered probes than in uncovered surface probes at 30 and 45 min into ischemia. CONCLUSIONS: Covering the µD probe increases the sensibility of the µD-technique in monitoring an ischemic insult and reperfusion in the liver. These findings confirm that the principle of surface µD works, possibly replacing need of intraparenchymatous placement of µD probes. Surface µD seemingly allows, noninvasively from an organ's surface, via the extracellular compartment, assessment of intracellular metabolic events. The finding that covered surface µD probes allows detection of local metabolic changes earlier than do intraparenchymatous probes, merit further investigation focusing on µD probe design.

Microcirculation changes during liver resection--a clinical study.

BACKGROUND: In this study we aimed to evaluate effects of liver resection on hepatic microcirculation. In addition we wanted to study if histological liver damage could be detected intra-operatively. PATIENTS AND METHODS: 40 patients undergoing hepatic resection were included and grouped according to if they were operated with a major or minor resection. Hepatic microcirculation measurements were made intra-operatively before and after liver resection with sidestream dark-field (SDF) imaging. Red blood cell velocity (RBCV), sinusoidal diameter and functional sinusoidal density were determined. RESULTS: After hepatic resection RBCV increased in both the minor and major groups (44 µm/s, P=0.016 and 121 µm/s, P=0.002). RBCV in patients with histological damages was 225 (148-464) µm/s vs. 161 (118-329) µm/s in patients with no damage (P=0.016). CONCLUSION: A hepatic resection leads to an increase of sinusoidal RBCV. SDF imaging could potentially be used to intraoperatively identify histological damages.

Fast-track program for liver resection--factors prolonging length of stay.

BACKGROUND/AIMS: Fast-track programs involving multi-modal measures to enhance recovery after surgery, reduce morbidity and decrease hospital length of stay (LOS) are used for different major surgical procedures. For liver resections, factors influencing LOS within a fast-track program have been studied only to a limited extent, which was the aim of the present study. METHODOLOGY: The present study comprises the first 64 patients included in a fast-track program for liver resections introduced in March 2012. Patient outcomes were compared to a historical cohort of patients (n=62) operated in 2009. Factors prolonging LOS was analyzed by uni- and multivariate analysis. RESULTS: Median LOS was 6 days (range 3-42 days) within the fast-track program as compared with 8 days (range 5-47 days) in the historical cohort (P=0.004). On multivariate analysis, factors increasing LOS in the fast-track group were found to be the presence of complication (P=0.018), extent of resection (major as compared to minor) (P=0.001) and inability to drink > 1250 ml on the day after surgery (P=0.002). CONCLUSION: Patients who can only drink limited amounts of fluid the day after liver resection represent a subset of patients that should be given special attention within a fast-track program.

Thoracic epidural anaesthesia reduces insulin resistance and inflammatory response in experimental acute pancreatitis.

AIMS: The activity of the sympathetic nervous system (SNS) is crucial at an early stage in the development of an inflammatory reaction. A study of metabolic events globally and locally in the early phase of acute pancreatitis (AP), implying hampered SNS activity, is lacking. We hypothesized that thoracic epidural anaesthesia (TEA) modulates the inflammatory response and alleviates the severity of AP in pigs. MATERIAL AND METHODS: The taurocholate (TC) group (n = 8) had only TC AP. The TC + TEA group (n = 8) had AP and TEA. A control group (n = 8) underwent all the preparations, without having AP or TEA. Metabolic changes in the pancreas were evaluated by microdialysis and by histopathological examination. RESULTS: The relative increase in serum lipase concentrations was more pronounced in the TC group than in TC + TEA and control groups. A decrease in relative tissue oxygen tension (PtiO2) levels occurred one hour later in the TC + TEA group than in the TC group. The maintenance of normoglycaemia in the TC group required a higher glucose infusion rate than in the TC + TEA group. The relative decrease in serum insulin concentrations was most pronounced in the TC + TEA group. CONCLUSION: TEA attenuates the development of AP, as indicated by changes observed in haemodynamic parameters and by the easier maintenance of glucose homeostasis. Further, TEA was associated with attenuated insulin resistance and fewer local pathophysiological events.

Unique antitumour effects of L-2,4 diaminobutyric acid on cultured hepatoma cells.

A single hepatoma cell line was grown in vitro and incubated with L-2,4 diaminobutyric acid (DAB), a non-metabolizable amino acid, under various conditions. The tumour cells were irreversibly damaged by incubation for 8 hours with 8 mmol/L of DAB. The tumour cell-destroying effect of DAB was dose- and time-dependent with no effect at a DAB concentration of 1.6 mmol/L. The presence of N-methyl alpha-aminoisobutyric acid (a specific substrate of amino acid transport system A) in the incubation medium abrogated the tumour cell destructive effect of DAB in a dose-dependent fashion. The presence of non-physiological amino acids in the incubation medium per se was not the cause of tumour cell destruction, since inclusion of alpha-amino-isobutyric acid and N-methyl alpha-aminoisobutyric acid in the incubation medium did not influence the viability of hepatoma cells. We conclude that the tumour cell destructive effect of DAB was the result of a huge and unlimited uptake of DAB energized by the Na(+)-gradient and that this uptake was not subjected to the law of saturation kinetics. This was combined with a tumour cell energy crisis in attempts to restore the Na(+)-gradient.

Surface microdialysis sampling: a new approach described in a liver ischaemia model.

We recently have shown that samples from microdialysis (MD) probes placed on the surface of the heart reflect metabolic events in the myocardium. This new interesting observation challenges us to consider whether surface application of MD applies to other parenchymatous organs and their surfaces. In 13 anesthetized pigs, transient liver ischaemia was achieved by occlusion of arterial and venous inflow to the liver. Two probes on liver surface and two in parenchyma were perfused with a flow rate of 1 µl per min (n = 13). An identical set-up was used for probes with a flow rate of 2 µl per min (n = 9). Samples were collected for every 15-min period during 60 min of baseline, 45 min of ischaemia and 60 min of reperfusion. Lactate, glucose, pyruvate and glycerol were analysed in MD samples. We focused on relative changes in the present study. There was a strong agreement in relative lactate and glucose levels between probes placed on liver surface and those on parenchyma. No significant differences in relative changes in lactate and glucose levels were seen between samples from surface probes and probes in liver parenchyma during equilibration, baseline, ischaemia or reperfusion with a flow rate of 1 µl per min. MD sampling applied on the liver surface is a new application area for the MD technique and may be used to monitor liver metabolism during both physiological and pathophysiological conditions.

Pancreaticojejunostomy: a valid operation in chronic pancreatitis?

OBJECTIVE: Patients with chronic pancreatitis and intractable pain may be candidates for surgical intervention and various types of surgery have been described over time. The objective of this study was to describe long-term outcome following pancreaticojejunostomy in patients with chronic pancreatitis. MATERIAL AND METHODS: Thirty-two patients with chronic pancreatitis underwent lateral pancreatiocojejunostomy and were then followed-up for 5 years. RESULTS: The short-term results on relief of abdominal pain were good, but seemed to deteriorate at long-term follow-up (5 years), as did pancreatic exocrine and endocrine function. A substantial number of patients admitted to continued alcohol abuse at 5-year follow-up (31%). CONCLUSIONS: Pancreaticojejunostomy in patients with chronic pancreatitis renders good pain relief. In effect, the deterioration in abdominal pain at long-term follow-up was in parallel with a tendency towards a decline in both exocrine and endocrine function and a continued alcohol abuse.

Iatrogenic bile duct injury--a cost analysis.

INTRODUCTION: Iatrogenic bile duct lesions following cholecystectomy represent a feared complication occurring in up to 0.9%. The aim of the present study was to estimate the total cost associated with both minor and major bile duct injuries. MATERIAL AND METHODS: Detailed information on 24 consecutive patients, out of which 14 were considered to have minor and 10 patients considered as having major bile duct injury, provided the underlying information that rendered calculations on average individual costs for both groups of injuries. RESULTS AND DISCUSSION: Calculating individual costs for minor and major bile duct injuries with actual incidences of cholecystectomies performed and the incidence of iatrogenic bile duct injury demonstrated that the total costs, including in-hospital cost, sick leave and loss of production, were substantial. For the management of minor bile duct injuries costs were within the range of 136,787-159,585 EUR and for the management of major bile duct injuries from 336,903-449,204 EUR per million inhabitants and year. The total costs for the management of all types of bile duct injuries were thus within the range of 473,690-608,789 EUR per million inhabitants annually for the society.