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Biomedical subjects

A Mehrabi

Publications and source records attributed to A Mehrabi.

At least 19 recordsLinked to original sources

Development and evaluation of a training module for the clinical introduction of the da Vinci robotic system in visceral and vascular surgery.

BACKGROUND: With the increasing use of the surgical robotic system in the clinical arena, appropriate training programs and assessment systems need to be established for mastery of this new technology. The authors aimed to design and evaluate a clinic-like training program for the clinical introduction of the da Vinci robotic system in visceral and vascular surgery. METHODS: Four trainees with different surgical levels of experience participated in this study using the da Vinci telemanipulator. Each participant started with an initial evaluation stage composed of standardized visceral and vascular operations (cholecystectomy, gastrotomy, anastomosis of the small intestine, and anastomosis of the aorta) in a porcine model. Then the participants went on to the training stage with the rat model, performing standardized visceral and vascular operations (gastrotomy, anastomosis of the large and small intestines, and anastomosis of the aorta) four times in four rats. The final evaluation stage was again identical to the initial stage. The operative times, the number of complications, and the performance quality of the participants were compared between the two evaluation stages to assess the impact of the training stage on the results. RESULTS: The operative times in the final evaluation stage were considerably shorter than in the initial evaluation stage and, except for cholecystectomies, all the differences reached statistical significance. Also, significantly fewer complications and improved quality for each operation in the final evaluation stage were documented, as compared with their counterparts in the initial evaluation stage. These improvements were recorded at each level of experience. CONCLUSIONS: The presented experimental small and large animal model is a standardized and reproducible training method for robotic surgery that allows evaluation of the surgical performance while shortening and optimizing the learning-curve.

Animals↗

[Evaluation of traditional German undergraduate surgical training. An analysis at Heidelberg University].

BACKGROUND: The medical faculty of Heidelberg University implemented a new problem-based clinical curriculum (Heidelberg Curriculum Medicinale, or Heicumed) in 2001. The present study analyses the evaluation data of two student cohorts prior to the introduction of Heicumed. Its aim was to specify problems of the traditional training and to draw conclusions for implementation of a new curriculum. METHODS: The evaluation instrument was the Heidelberg Inventory for the Evaluation of Teaching (HILVE-I). The data were analysed calculating differences in the means between defined groups, with the 13 primary scales of the HILVE I-instrument as dependent variables. RESULTS: Teaching method and subject had no systematic influence on evaluation results. Thus, didactic lecture in orthopedic surgery achieved better results than small group tutorials, while the data on vascular and general surgery showed opposite results. Major factors for success were continuity and didactic training of lecturers and tutors. This is convincingly reflected by the results of the lecture course "Differential diagnosis in general surgery". The good evaluation data on small group tutorials resulted largely from the "participation" and "discussion" scales, which represent interactivity in learning. CONCLUSION: The results of the present study suggest the importance of two major pedagogic ideas: continuity and didactic training of lecturers and tutors. These principles were widely implemented in Heicumed and have contributed to the success of the new curriculum.

Attitude of Health Personnel↗

Evaluation of microperfusion disturbances in the transplanted liver after Kupffer cell destruction using GdCl3: an experimental porcine study.

BACKGROUND: Organ function after liver transplantation is determined by ischemia-reperfusion injury. Destruction of Kupffer cells with gadolinium chloride (GdCl3) has been shown to have a possible preventive effect on the extent of this injury, which can be extrapolated by analyzing the distribution of hepatic microperfusion. The aim of this study was to evaluate the protective effect of GdCl3 on disturbances of microperfusion in the transplanted liver. METHODS: Landrace pigs were randomly divided into three groups. In the control group (CG; n=6) a mapping of the native liver was conducted. For mapping, the four hepatic liver lobes were named from right to left with A to D and every lobe was divided into three vertical segments (cranial, medial, and caudal). In each of these 12 areas, microperfusion was quantified using a thermodiffusion probe (TD [mL/100 g/min]). The other two groups were considered as transplanted treated group (TTG; n=10) and transplanted nontreated group (TnTG; n=10). The TTG received an infusion of 20 mg/kg GdCl3 intravenously 24 hours before organ harvesting. Then standardized orthotopic liver transplantation was performed. In TnTG, standardized orthotopic liver transplantation was carried out without prior GdCl3 injection. In the recipients, the microperfusion of transplanted livers were mapped in both TnTG and TTG, in two different time points (1 hour [n=5] and 24 hours (n=5]) after reperfusion. RESULTS: A significant reduction of macrophages in the TTG livers in comparison to the CG and TnTG livers was observed (P<.05). However, the number of macrophages in CG and TnTG livers showed no significant difference (P>.05). Regarding liver microperfusion, in TnTG, a marked heterogeneity was detected in the livers after reperfusion. Significant differences between liver lobes (horizontal planes; P=.032) and vertical layers of intralobar liver parenchyma (P=.029) were observed. The same pattern was seen in TTG livers after reperfusion and a significant difference between horizontal (P=.024) and vertical layers (P=.018) of liver tissue were observed. Comparing intralobar regional flow data between vertical planes 24 hours after reperfusion still showed a prominent variation of hepatic tissue perfusion in TnTG livers (P=.028). Within the same horizontal layers, no significant differences between lobes were measured anymore (P=.16). Contrary to TnTG, in TTG, a homogenous pattern of regional liver tissue perfusion was recorded 24 hours after reperfusion. Comparison of TD data on the liver regions showed no significant microperfusion differences in either horizontal (P=.888) or vertical (P=.841) layers. CONCLUSIONS: Application of GdCl3 resulted in a significant reduction of Kupffer cells. Twenty four hours after transplantation microperfusion showed a homogeneous pattern, which constituted an earlier and better recovery of the transplanted liver. Therefore, destruction of Kupffer cells reduced ischemia-reperfusion injury and seemed to be responsible for the early recovery of microperfusion disturbances and thus for an improvement of graft function.

Animals↗

The role and value of sirolimus administration in kidney and liver transplantation.

Enormous advancements in visceral transplantation have led to significant improvements in the quality of life of patients. However, despite these developments, the average graft half-life after transplantation has remained almost unchanged and chronic rejection is still considered a major problem. In this regard, more concerns have shifted to factors influencing long-term graft survival, patient survival, and quality of life. To achieve this goal, detrimental effects of immunosuppressive (IS) agents, which have deleterious influence on the quality of life and/or patient survival, should be reduced. In the course of recent years, the transplant community has worked on reducing these side effects by developing new ISs, employing new combination regimens, or finding and adjusting optimal dosages and blood level concentrations. Among the IS agents, the antifungal, antitumoral and IS activity of mammalian target of rapamycin (mTOR) inhibitors without nephrotoxicity, have received special attention regarding this new class of IS. Sirolimus (SRL), as the first member of mTOR inhibitors, has been utilized in many clinical trials with respect to its benefit-risk assessment. In our review, the clinical evolution of SRL, as well as the evidence-based clinical benefits of SRL in kidney and liver transplantation (KTx, LTx), are summarized. Various studies of SRL in KTx and LTx have shown that combination therapy with SRL will enrich the variety of IS modalities. It also can be regarded as a safe base therapy to which other necessary drugs can be added. In addition to the enhanced acute rejection prophylaxis, and in contrast to the calcineurin inhibitors (CNI) and steroids, this drug solely does not have common side effects such as nephrotoxicity, neurotoxicity, diabetes mellitus and hypertension. Moreover, this agent might diminish vasculopathic processes that mediate chronic allograft nephropathy (CAN). Therefore, by reducing the likelihood of CAN it can decrease the rate of long-term organ failure. One possibly desirable characteristic of SRL is its antiproliferative effect, which could provoke antitumoral or antiatherogenic activity following transplantation. Despite all promising impacts of SRL in organ transplantation, there are some concerns regarding the adverse effects of this drug, for instance dyslipidemia, pneumonitis and wound healing problems. However, the majority of these side effects can be reduced or ceased by careful dose adjustments and correct timing of use. In conclusion, after a decade of both in vivo and in vitro studies on SRL, it can be advocated that SRL is a promising, potent and effective IS agent as it reduces the rate of acute rejection episodes in de novo transplants. It could improve the quality of life, graft and patient survival rate, and achieve excellent outcomes with few adverse effects when wisely used in combination with other immunosuppressants.

Graft Rejection↗

Immunosuppressive standards in simultaneous kidney-pancreas transplantation.

Simultaneous pancreas-kidney transplantation is an established procedure for patients with type I diabetes and end-stage renal disease. Continuous advances in the operation techniques with consequent reduction of perioperative morbidity and mortality and the introduction of modern immunosuppressive agents improved not only patients but also graft survival and significantly decreased rejection episodes of both kidney and pancreas grafts. Availability of a variety of new immunosuppressants in the clinical routine and increasing experience of the transplant specialists allowed further developments of therapeutic schemes with application of induction and maintenance immunosuppressive protocols. In this article, we summarize the current status of immunosuppressive regimens in simultaneous pancreas and kidney transplantation.

Graft Rejection↗

How to increase inflow in liver transplantation.

Liver transplantation (LTx) has become the treatment of choice for selected cases of benign and malignant liver disease. Despite becoming increasingly safer in recent years this procedure still incurs several serious postoperative complications. The most significant surgical complications are related to surgical technique, particularly the reconstruction and/or anastomosis of the hepatic artery. Arterial hypoperfusion may lead to graft failure, sepsis, or ischemic biliary lesions. In this review we focus on the Achilles' heel of LTx: the hepatic artery. We provide transplant surgeons with an overview of the technical options that are available to increase arterial inflow and subsequently improve patient outcome. We exemplify some of the discussed techniques using a liver transplant case with an eventful postoperative course because of arterial complications.

Adult↗

Biliary complications after liver transplantation.

Biliary complications remain a substantial cause of morbidity following liver transplantation. They have been reported to occur in a rate of 10-15% of full-size transplantations and may be higher in living donor, split or reduced size liver transplantations. The most common biliary complications following liver transplantations are leaks and strictures. In both, the incidence varies with respect to type of graft and donor as well as the type of biliary anastomosis. The management of the biliary complications requires a multidisciplinary approach and has changed over the past decade, favoring endoscopic and radiological techniques. Surgical revision including retransplantation is reserved for patients in whom endoscopic and interventional modalities are unsuccessful.

Biliary Tract Diseases↗

Wound complications following kidney and liver transplantation.

Advances in surgical techniques and immunosuppression (IS) have led to an appreciable reduction in postoperative complications following transplantation. However, wound complications as probably the most common type of post-transplantation surgical complication can still limit these improved outcomes and result in prolonged hospitalization, hospital readmission, and reoperation, consequently increasing overall transplant cost. Our aim was to review the literature to delineate the evidence-based risk factors for wound complications following kidney and liver transplantation (KTx, LTx), and to present the preventive and therapeutic modalities for this bothersome morbidity. Generally, wound complications are categorized as superficial and deep wound dehiscences, perigraft fluid collections and seroma, superficial and deep wound infections, cellulitis, lymphocele and wound drainage. The results of several studies showed that the most important risk factors for wound complications are IS and obesity. Additionally, there are surgical and/or technical factors, including type of incision, reoperation, and surgeon's expertise, as well as comorbidities such as advanced age, diabetes mellitus, malnutrition, and uremia. Preventive management of wound complications necessitates defining their etiological factors so that their detrimental effects on healing processes can be addressed and reduced. IS modalities and agents, especially sirolimus (SRL), and steroids (ST) should be adjusted according to the patient's co-existing risk factors. SRL should be administered three months after transplantation and ST should be tapered as soon as possible. A body mass index (BMI) lower than 30 kg/m2 is advisable for inclusion in a transplantation program, but higher BMIs do not exclude recipients. Surgical risk factors can be prevented by applying precise surgical techniques. Therapeutic modalities must focus on the most efficient and cost-effective medications and/or interventions to facilitate and improve wound healing.

Humans↗

[Relevance of surgical outpatient clinics in academic university centers to health care in Germany].

During the observation period between 2001 and 2003, all outpatient surgical therapy, including degrees of urgency, surgical care volume, regional provenance of patients, diagnoses, and referral channels were prospectively analysed at the Surgical Department of the University of Heidelberg, Germany. The data gathered do not merely describe the volume and characteristics of care encountered at this academic surgical institution but also provide further insight into the variability of resource utilisation and associated patient flow. Additionally, a retrospective evaluation using structured interviews and questionnaires was performed to differentiate and quantify patient care, teaching, and research activities. This study illustrates the high relevance of academic outpatient institutions to regional provision of general surgical care in Germany. There is a clear dominance of medical support functions, while research and teaching activities are of only minor relevance and realised particularly in subspecialty clinics. These data should give important stimuli for the future planning of health care in Germany. Outpatient clinics for general surgery appear to be an excellent basis for regional models of integrated health care delivery in the future.

Academic Medical Centers↗

Laparoscopic organ retrieval for living donor liver transplantation does not prevent graft injury.

The cause of transplant failure may be difficult to define. However, organ retrieval before preservation and transplantation is an important factor. Organ manipulation during harvesting, which is inevitable with most techniques, leads to injury upon reperfusion including microcirculatory disturbances. Recently, laparoscopic organ retrieval has been successfully performed for human living donor liver transplantation (LDLT). Pneumoperitoneum for laparoscopy changes the pattern of hepatic blood flow. To study the effects of pneumoperitoneum on the graft prior to cold storage, livers from Sprague-Dawley rats underwent pneumoperitoneum with an intra-abdominal pressure of 8 mm Hg for 90 minutes. Subsequently, intravital microscopy was performed to assess intrahepatic microcirculation and transaminases were measured. Serum transaminases increased 1.5-fold compared with sham controls (P < .05). Intrahepatic microcirculation was significantly disturbed immediately after pneumoperitoneum. If this is confirmed in humans, laparoscopic organ retrieval for LDLT would be expected to decrease graft quality and not be beneficial in liver transplantation.

Animals↗

Guidelines for prevention and management of complications following kidney transplantation in rats.

Kidney transplantation in rats is a useful model for microsurgery, transplantation, and immunology studies. Our aim was to analyze various techniques of kidney transplantation in rats with emphasis on guidelines for the prevention and management of complications. Complications were categorized into general, vascular, and urological types and respectively attributed to long transplantation time, core body temperature drop, nonreplaced intraoperative blood loss, anastomosis failure, and ureteral anastomoses with stents or cannulas, which increase the risk of calculus formation. In conclusion, to decrease the complication rates the animal should be placed on a heating pad. For hemodynamic stability NaCl should be administered subcutaneously. To reduce the risk of thrombosis, ice-cold saline containing heparin should be administered. Vascular complications, which mainly depend on the microsurgeon's expertise, can be prevented by meticulous surgical technique (preferably an end-in-end anastomosis). The main urinary complications can be minimized by avoiding stents and cannulas and focusing on using techniques like the bladder-patch technique.

Animal Husbandry↗

Gadolinium chloride-induced improvement of postischemic hepatic perfusion after warm ischemia is associated with reduced hepatic endothelin secretion.

Selective Kupffer cell blockade by gadolinium chloride (GdCl(3)) pretreatment of liver donors previously proved to be effective in reducing ischemia/reperfusion injury in rat liver transplants. Physiological mechanisms of this effect have not been specified so far. Vasoactive peptides are involved in liver blood flow regulation. We tested the hypothesis, that hepatic hemodynamic effects of GdCl(3) pretreatment are mediated by intrahepatic endothelin-1 (ET) secretion in a standardized porcine model of warm liver ischemia and reperfusion. Standardized warm hepatic ischemia (45 min) was induced after laparotomy in intubation narcoses (ITN) by Pringle-maneuver in pigs (n = 12). Animals were either pretreated with GdCl(3) (20 mg/kg i.v.) or sodium chloride 0.9% (control group) in a randomized manner 24 h before investigation. Relaparotomy was performed at day 7. Before, during ischemia and until 6 h after liver reperfusion, transhepatic blood flow (portal venous + hepatic artery flow) was defined by ultrasonic flow probes and hepatic parenchymous microcirculation evaluated by implanted thermodiffusion electrodes. ET plasma concentrations were analyzed (commercial RIA) at all time points in the hepatic veins after selective canulation. GdCl(3) pretreatment of animals markedly improved hepatic macro- and microperfusion before and particularly after warm ischemia. Mean ET plasma concentrations in the hepatic vein were significantly lower before, 6 h and 7 days after ischemia, compared with controls. Kupffer cell destruction by GdCl(3) pretreatment improves hepatic micro- and macroperfusion after warm ischemia, thus indicating reduced ischemia/reperfusion injury. Documented reduction of postischemic liver blood flow impairment after GdCl(3) pretreatment could be mediated by a decreased hepatic ET secretion, as hemodynamic effects were associated with significantly reduced ET plasma levels in hepatic veins.

Animals↗

Fewer adhesions induced by laparoscopic surgery?

BACKGROUND: Laparoscopic surgery has potential theoretical advantages over open surgery in reducing the rate of adhesion formation, but very few comparative studies are available to prove this. METHODS: A literature search was performed within Medline and Cochrane databases using the key words: adhesion*, adhesiolysis, laparoscop*, laparotomy, open surgery. Further articles were identified from the reference lists of retrieved literature. Both clinical and experimental studies comparing laparoscopy and laparotomy with regard to adhesion formation were retained. In each article, the rates of adhesion formation were identified or deduced for the operative site, access wound site, and distant sites. RESULTS: Fifteen studies from 1987 to 2001 were identified. Most studies assessed the operative site. Thus, three clinical studies and six experimental ones found fewer adhesions following laparoscopy than laparotomy, while other five experimental studies found similar adhesion rates for the two surgical methods. There were fewer adhesions to trocar wounds than to the laparotomy wounds in seven studies and equal rates of adhesion in one study. The problem of distant adhesions is poorly represented in literature; three studies favored laparoscopy as being followed by fewer adhesions. Because of the important differences between studies with regard to the design, end points, and statistical calculations, a metaanalysis could not be achieved. The conclusion is based on the prevalence of evidence. CONCLUSIONS: All clinical studies and most of the experimental studies found a reduction of adhesion formation after laparoscopic surgery compared to open surgery.

Animals↗

Circulatory and respiratory complications of carbon dioxide insufflation.

BACKGROUND: Although providing excellent outcome results, laparoscopy also induces particular pathophysiological changes in response to pneumoperitoneum. Knowledge of the pathophysiology of a CO(2) pneumoperitoneum can help minimize complications while profiting from the benefits of laparoscopic surgery without concerns about its safety. METHODS: A review of articles on the pathophysiological changes and complications of carbon dioxide pneumoperitoneum as well as prevention and treatment of these complications was performed using the Medline database. RESULTS: The main pathophysiological changes during CO(2) pneumoperitoneum refer to the cardiovascular system and are mainly correlated with the amount of intra-abdominal pressure in combination with the patient's position on the operating table. These changes are well tolerated even in older and more debilitated patients, and except for a slight increase in the incidence of cardiac arrhythmias, no other significant cardiovascular complications occur. Although there are important pulmonary pathophysiological changes, hypercarbia, hypoxemia and barotraumas, they would develop rarely since effective ventilation monitoring and techniques are applied. The alteration in splanchnic perfusion is proportional with the increase in intra-abdominal pressure and duration of pneumoperitoneum. CONCLUSION: A moderate-to-low intra-abdominal pressure (<12 mm Hg) can help limit the extent of the pathophysiological changes since consecutive organ dysfunctions are minimal, transient and do not influence the outcome.

Animals↗

Robot-assisted abdominal surgery.

BACKGROUND: Robotic assistance or telemanipulation is the latest technological advance in minimally invasive surgery. Its future implementation will depend on the advantages that it can provide over standard laparoscopy or open surgery. METHODS: All Medline-cited papers (from case reports to reviews) about telemanipulators used in visceral surgery were assessed. The data in each paper were analysed to enable an up-to-date review of robot-assisted abdominal surgery by the most advanced telemanipulator (da Vinci). RESULTS: Most papers presented case series demonstrating the feasibility of robotic technology in performing a specific procedure. Comparative studies of robot-assisted surgery versus standard laparoscopic or open surgery were usually matched cohort studies. They generally showed an increased operating time for robot-assisted procedures but with similar rates of conversion, intraoperative and postoperative complications, and mortality in comparison to those of laparoscopic surgery. Consistent long-term follow-up data were missing and only one randomized clinical trial was conducted. CONCLUSION: Robot-assisted surgery appears safe and feasible for certain standard surgical procedures. However, at its current level of development, it offers no clear, significant advantage over standard laparoscopic techniques.

Abdomen↗

The impact of carbon dioxide and helium insufflation on experimental liver metastases, macrophages, and cell adhesion molecules.

BACKGROUND: Laparoscopic insufflation, proposed to reduce hepatic perfusion, may enhance hepatic tumor spread. It is unknown whether intraabdominal pressure or the gas itself influences hepatic tumor growth. In contrast to carbon dioxide, the alternative gas helium is believed to reduce malignant cell growth. METHODS: For this study, 36 WAG/Rij rats were randomized in two experimental groups. The animals were laparoscopically insufflated with carbon dioxide ( n = 19) or helium gas ( n = 17). Liver metastases were induced by laparoscopic injection of 50,000 CC531 cells into the portal vein. Macroscopic and microscopic analyses of CC531 tumor cell growth, macrophages, and CD44v5, v6 were performed. Data were analyzed by Kruskal-Wallis, Dunn, and Holm tests. RESULTS: No significant differences in macroscopic and microscopic analyses were found between carbon dioxide and helium gas insufflations ( p > 0.05). CONCLUSIONS: Recent studies have shown that insufflation with carbon dioxide may result in increased hepatic tumor growth. The current study comparing carbon dioxide and helium insufflations could show for the first time either oncologic nor immunologic differences in relation to the liver between two different gases. In conclusion, elevated intraabdominal pressure during gas insufflation is responsible for hepatic disadvantages during pneumoperitoneum, not carbon dioxide gas itself.

Animals↗

Characterization of hepatic parenchymous perfusion heterogeneity and regional flow kinetics after porcine liver transplantation.

BACKGROUND: In clinical practice, a heterogeneous hepatic tissue microperfusion (MC) is often observed after liver resection or transplantation (LTx). Nevertheless this hepatic perfusion phenomenon has never been really quantified with respect to its anatomic distribution and time course in detail. The aim of the study was to characterize liver perfusion heterogeneity and local flow kinetics both in the physiological situation and after standardized ischemia and reperfusion using an established model of porcine LTx. METHODS: Regional distribution of hepatic MC in healthy native porcine livers (control group; n = 8) was analyzed in comparison with data derived 60 min, 24 h, and 72 h after porcine LTx (transplantation group; n = 8 each subgroup; cold ischemia time: 5.7 +/- 1.2 h). MC was measured with implanted thermal diffusion electrodes (TD). Flow in hepatic artery and portal vein was continuously detected by ultrasonic probes. For standardization of measurement localizations, porcine liver lobes were divided anatomically into three horizontal layers (cranial, medial, caudal), defining 12 distinct hepatic measurement regions. RESULTS: In the control group, a homogenous liver MC with a mean flow of 81.6 +/- 13.9 ml/100 g/min was detected in all regions. After LTx, a marked MC heterogeneity was noted 60 min after reperfusion. MC rehomogenization was first documented within horizontal liver planes 24 h later. Comparison of MC between planes showed persisting heterogeneity with a significant intralober drop of mean MC in the cranio-caudal direction. Complete MC rehomogenization (both between horizontal and vertical liver planes) was detected 72 h after reperfusion. Still, an overall reduction of mean liver perfusion by about 15% was existent. CONCLUSIONS: A homogenous tissue perfusion was observed in healthy porcine livers. In contrast, marked heterogeneity of hepatic MC was detected after LTx. Heterogeneity presents as a very dynamic and temporary phenomenon. Early horizontal flow rehomogenization and reconstitution of normal blood flow, particularly primarily in the cranial liver layers, appear to be characteristic features during early flow reconstitution after postischemic reperfusion. Due to heterogeneity and time-dependent flow dynamics, measurement of MC volumes at single hepatic regions may not always allow a valid characterization of liver perfusion quality during the first 24 h after postischemic reperfusion.

Animals↗

Experimental monitoring of hepatic glucose, lactate, and glutamate metabolism by microdialysis during surgical preparation of the liver hilus.

Mechanical liver manipulation can lead to hepatic microcirculation (MC) impairment. The pathobiochemical relevance of this phenomenon is not fully understood. Microdialysis (MD) allows a quantification of metabolic products in interstitial fluid, thus enabling analysis of the hepatic metabolic state during changes of liver perfusion. The aim of the study was to quantify the functional effects of standardized surgical liver preparation both on liver metabolism and microperfusion. Two groups of animals (pigs, n = 25) were formed: In the trial group (TG; n = 13) the liver was mobilized, followed by hilar preparation. In the control group (CG; n = 12) mobilization of the liver without hilar dissection was performed. Surgical manipulation was followed by an observation in both groups. Hepatic interstitial glucose, lactate, and glutamate concentrations were detected by MD and liver MC by thermodiffusion. During liver mobilization MC decreased significantly in both groups (TG; 86.7 +/- 2.0 to 73.4 +/- 2.3 ml/100 g min; and CG; 88.3 +/- 3.1 to 71.9 +/- 2.2 ml/100 g/min). In the trial group levels decreased further during hilar preparation reaching minimal values of 65.6 +/- 2.8. After preparation MC recovered to baseline. Glucose, lactate, and glutamate concentrations increased significantly during liver mobilization in the trial (glucose; 0.52 +/- 0.13 to 0.88 +/- 0.19 mmol/L; lactate; 0.34 +/- 0.07 to 0.54 +/- 0.07 mmol/L; glutamate; 34.5 +/- 3.6 to 52.6 +/- 8.0 micromol/L) and control group (glucose; 0.58 +/- 0.06 to 0.95 +/- 0.13 mmol/L; lactate; 0.30 +/- 0.06 to 0.49 +/- 0.07 mmol/L; glutamate; 32.9 +/- 2.36 to 56.1 +/- 5.12 micromol/L). Throughout hilus preparation maximum values could be measured in TG (glucose; 1.69 +/- 0.34; lactate; 0.90 +/- 0.18; glutamate; 63.5 +/- 7.2). After termination of mobilization or preparation baseline concentrations were reached again. MD allows monitoring of metabolic changes in hepatic parenchyma. Surgical liver preparation leads to changes of intrahepatic glucose, lactate, and glutamate levels (without alterations of parameters in systemic plasma) along with hepatic MC impairment. Reconstitution of hepatic MC was accompanied by rapid normalization of metabolic parameters. By measuring specific parameters, MD could prove to be of use for functional assessment of metabolic effects due to MC disturbances.

Animals↗