umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Methodological aspects on microdialysis sampling and measurements
Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology. (Enheten för Anestesi och Intensivvård)
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 [en]
Microdialysis, liver ischemia, heart ischemia, epicardium, liver parenchyma, CMA 600, metabolism
National Category
Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
URN: urn:nbn:se:umu:diva-37464ISBN: 978-91-7459-097-5 (print)OAI: oai:DiVA.org:umu-37464DiVA: diva2:360737
Public defence
2010-11-26, Norrlands universitetssjukhus, Betula, 6M, Norrlands universitetssjukhus, 90185 Umeå, 09:00 (Swedish)
Opponent
Supervisors
Available from: 2010-11-11 Created: 2010-11-04 Last updated: 2012-03-06Bibliographically approved
List of papers
1. An assessment of calibration and performance of the microdialysis system
Open this publication in new window or tab >>An assessment of calibration and performance of the microdialysis system
2005 (English)In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 39, no 3-4, 730-734 p.Article in journal (Refereed) Published
Abstract [en]

To improve the reliability of microdialysis measurements of tissue concentrations of metabolic substances, this study was designed to test both the performance and the internal validity of the microdialysis methods in the hands of our research group. The stability of the CMA 600 analyser was tested with a known glucose solution in 72 standard microvials and in 48 plastic vials. To evaluate if variation in sampling time makes any difference in sample concentration (recovery), sampling times of 10, 20 and 30 min were compared in vitro with a constant flow rate of 1 microl/min. For testing of sampling times at different flow rates, an in vitro study was performed in which a constant sample volume of 10 microl was obtained. With the no net flux method, the actual concentration of glucose and urea in subcutaneous tissue was measured. The CMA 600 glucose analysis function was accurate and stable with a coefficient of variability (CV) of 0.2-0.55%. There was no difference in recovery for the CMA 60 catheter for glucose when sampling times were varied. Higher flow rates resulted in decreased recovery. Subcutaneous tissue concentrations of glucose and urea were 4.4 mmol/l and 4.1 mmol/l, respectively. To conclude, this work describes an internal validation of our use of the microdialysis system by calibration of vials and catheters. Internal validation is necessary in order to be certain of adequate sampling times, flow rates and sampling volumes. With this in mind, the microdialysis technique is useful and appropriate for in vivo studies on tissue metabolism.

Place, publisher, year, edition, pages
Elsevier, 2005
Keyword
Calibration, Chemistry; Pharmaceutical/*methods, Drug Industry, Evaluation Studies as Topic, Glucose/analysis, Microdialysis/instrumentation/*methods, Quality Control, Reference Standards, Reproducibility of Results, Technology; Pharmaceutical/*methods, Time Factors, Urea/pharmacology
National Category
Anesthesiology and Intensive Care
Identifiers
urn:nbn:se:umu:diva-6813 (URN)10.1016/j.jpba.2005.04.036 (DOI)15939565 (PubMedID)
Available from: 2007-12-18 Created: 2007-12-18 Last updated: 2017-12-14Bibliographically approved
2. Optimised sample handling in association with use of the CMA 600 analyser
Open this publication in new window or tab >>Optimised sample handling in association with use of the CMA 600 analyser
Show others...
2008 (English)In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 48, no 5, 940-945 p.Article in journal (Refereed) Published
Abstract [en]

A large degree of variability for batched analysis of serially collected microdialysis samples measured with the CMA 600 analyser has been described. This study was designed to identify sources of variability related to sample handling. Standard concentrations of four solutes were placed in microdialysis vials and then stored and analysed at intervals. Results were analysed for variability related to vial and cap type, duration and temperature of storage, centrifugation and re-analysis. The main results were that centrifugation of samples reduced variability. When a batch of 24 samples was analysed, the use of crimp caps reduced evaporation. Samples in glass vials with crimp caps could be stored in a refrigerator for up to 14 days without large variability in concentration compared to plastic vials which demonstrated variability already when stored for more than 1 day. We conclude that variability in microdialysis results can occur in relation to storage and analysis routines if routines are not optimised concerning evaporation. Centrifugation before analyses, glass vials with crimp caps even during frozen storage, and attention to minimal times for samples to be uncapped during analysis all contribute to minimise variability in the handling and analysis of microdialysis samples.

Place, publisher, year, edition, pages
Elsevier, 2008
Keyword
Microdialysis; CMA 600; Microdialysis validation; Microdialysis sample; Microdialysis sample storage
Identifiers
urn:nbn:se:umu:diva-31392 (URN)10.1016/j.jpba.2008.08.010 (DOI)0731-7085 (Print) (ISBN)
Available from: 2010-02-10 Created: 2010-02-10 Last updated: 2017-12-12Bibliographically approved
3. Detection of myocardial ischaemia using surface microdialysis on the beating heart
Open this publication in new window or tab >>Detection of myocardial ischaemia using surface microdialysis on the beating heart
Show others...
2011 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 3, 175-181 p.Article in journal (Refereed) Published
Abstract [en]

Microdialysis (MD) can be used to study metabolism of the beating heart. We investigated whether microdialysis results obtained from epicardial (surface) sampling reflect acute changes in the same way as myocardial sampling from within the substance of the ventricular wall. In anaesthetized open-thorax pigs a coronary snare was placed. One microdialysis probe was placed with the sampling membrane intramyocardially (myocardial), and a second probe was placed with the sampling membrane epicardially (surface), both in the area which was made ischaemic. Ten minutes collection intervals were used for microdialysis samples. Samples from 19 pigs were analysed for lactate, glucose, pyruvate and glycerol during equilibration, baseline, ischaemia and reperfusion periods. For both probes (surface and myocardial), a total of 475 paired simultaneous samples were analysed. Results from analyses showed no differences in relative changes for glucose, lactate and glycerol during baseline, ischaemia and reperfusion. Surface microdialysis sampling is a new application of the microdialysis technique that shows promise and should be further studied.

Keyword
epicardium; heart; ischaemia; metabolism; microdialysis; myocardium
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-39564 (URN)10.1111/j.1475-097X.2010.00995.x (DOI)21091606 (PubMedID)
Available from: 2011-02-01 Created: 2011-02-01 Last updated: 2017-12-11Bibliographically approved
4. Comparison between outcome of  surface and intraparenchymatous sampling using microdialysis in an experimental liver ischemia model
Open this publication in new window or tab >>Comparison between outcome of  surface and intraparenchymatous sampling using microdialysis in an experimental liver ischemia model
Show others...
(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
Microdialysis, liver, ischemia, surface probe, metabolism.
National Category
Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
urn:nbn:se:umu:diva-37467 (URN)
Available from: 2010-11-04 Created: 2010-11-04 Last updated: 2015-09-15Bibliographically approved

Open Access in DiVA

fulltext(3685 kB)1736 downloads
File information
File name FULLTEXT01.pdfFile size 3685 kBChecksum SHA-512
64762394dfd02b0b19a9da2018bf5acd02357106de0f4fed883b2be9cfd8e72d6aee945f223a3181f0ff942cda01140059139c5928070ab0a48bac8d8b3c6c88
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Abrahamsson, Pernilla
By organisation
Anaesthesiology
Anesthesiology and Intensive Care

Search outside of DiVA

GoogleGoogle Scholar
Total: 1736 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 961 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf