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Comparison between outcome of  surface and intraparenchymatous sampling using microdialysis in an experimental liver ischemia model
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology. (Enheten för Anestesi och Intensivvård)
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.ORCID iD: 0000-0002-5325-2688
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Introduction. We recently have shown that samples from 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.

Material and methods.  In thirteen anesthetized pigs transient liver ischemia 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/min (n=13). An identical set up was used for probes with a flow rate of 2 µL/min (n=9). Samples were collected for every 15 minute period during 60 minutes of baseline, 45 minutes of ischemia and 60 minutes of reperfusion. Lactate, glucose, pyruvate and glycerol were analysed in MD samples. We focused on relative changes in the present paper.

Results. There was a strong agreement in relative lactate and glucose levels between probes placed on liver surface and parenchyma. No significant differences in relative changes of lactate and glucose levels were seen between samples from surface probes and probes in liver parenchyma during equilibration, baseline, ischemia or reperfusion with a flow rate of 1 µL/min.

Conclusion. MD sampling applied on the liver surface is a new application area for the MD technique, and may be used to monitor liver metabolism both during physiological and pathophysiological conditions.

Keyword [en]
Microdialysis, liver, ischemia, surface probe, metabolism.
National Category
Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
URN: urn:nbn:se:umu:diva-37467OAI: oai:DiVA.org:umu-37467DiVA: diva2:360747
Available from: 2010-11-04 Created: 2010-11-04 Last updated: 2015-09-15Bibliographically approved
In thesis
1. Methodological aspects on microdialysis sampling and measurements
Open this publication in new window or tab >>Methodological aspects on microdialysis sampling and measurements
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background:     The microdialysis (MD) technique is widely spread and used both experi­mentally and in clinical practice. The MD technique allows continuous collection of small molecules such as glucose, lactate, pyruvate and glycerol. Samples are often analysed using the CMA 600 analyser, an enzymatic and colorimetric analyser.  Data evaluating the performance of the CMA 600 analysis system and associated sample han­dling are sparse. The aim of this work was to identify sources of variability related to han­dling of microdialysis samples and sources of error associated with use of the CMA 600 analyser. Further, to develop and compare different application techniques of the micro­dialysis probes both within an organ and on the surface of an organ.

 Material and Methods:  Papers I and II are mainly in vitro studies with the exception of the No Net Flux calibration method in paper I where a pig model (n=7) was used to exam­ine the true concen­tration of glucose and urea in subcutaneous tissue. Flow rate, sampling time, vial and caps material and performance of the analyser device (CMA 600) were examined. In papers III and IV normoventilated anaesthetised pigs (n=33) were used. In paper III, heart ischemia was used as intervention to compare microdialysis measurements in the myocardium with corresponding measurements on the heart surface. In paper IV, microdialysis measurements in the liver parenchyma were compared with measurements on the liver surface in associa­tion with induced liver ischemia. All animal studies were approved by the Animal Experi­mental Ethics Committee at Umeå University Sweden.

Results:  In paper I we succeeded to measure true concentrations of glucose (4.4 mmol/L) and Urea (4.1 mmol/L) in subcutaneous tissue. Paper II showed that for a batch analyse of 24 samples it is preferred to store microdialysis samples in glass vials with crimp caps. For reliable results, samples should be centrifuged before analysis. Paper III showed a new application area for microdialysis sampling from the heart, i.e. surface sampling. The sur­face probe and myocardial probe (in the myocardium) showed a similar pattern for glucose, lactate and glycerol during baseline, short ischemic and long ischemic interventions. In paper IV, a similar pattern was observed as in paper III, i.e. data obtained from the probe on the liver surface showed no differences compared with data from the probe in liver paren­chyma for glucose, lactate and glycerol concentrations during baseline, ischemic and reperfusion interven­tions.

Conclusion:  The MD technique is adequate for local metabolic monitoring, but requires methodological considerations before starting a new experimental serie. It is important to consider factors such as flow rate, sampling time and handling of samples in association with the analysis device chosen. The main finding in this thesis is that analyses of glucose, lactate and glycerol in samples from the heart surface and liver surface reflect concentra­tions sampled from the myocardium and liver parenchyma, respectively.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2010. 59 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1380
Keyword
Microdialysis, liver ischemia, heart ischemia, epicardium, liver parenchyma, CMA 600, metabolism
National Category
Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
urn:nbn:se:umu:diva-37464 (URN)978-91-7459-097-5 (ISBN)
Public defence
2010-11-26, Norrlands universitetssjukhus, Betula, 6M, Norrlands universitetssjukhus, 90185 Umeå, 09:00 (Swedish)
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Available from: 2010-11-11 Created: 2010-11-04 Last updated: 2012-03-06Bibliographically approved

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Abrahamsson, PernillaÅberg, Anna-MajaWinsö, OlaJohansson, GöranHaney, Michael

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