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Continuous monitoring of the bronchial epithelial lining fluid by microdialysis.

Tyvold SS, SolligÄrd E, Lyng O, Steinshamn SL, Gunnes S, Aadahl P - Respir. Res. (2007)

Bottom Line: Accuracy was defined as [bronchial-MD] divided by [arterial-MD] in percent.With correction by the arteriobronchial urea gradient accuracy was mean 79.0% (57.3-108.1%) with a CV of 17.0%.Urea as a marker of catheter functioning enhances bronchial MD and makes it useful for monitoring substantial changes in the composition of the ELF.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesia and Intensive Care, St, Olavs Hospital, Trondheim, Norway. stig.s.tyvold@ntnu.no

ABSTRACT

Background: Contents of the epithelial lining fluid (ELF) of the bronchi are of central interest in lung diseases, acute lung injury and pharmacology. The most commonly used technique broncheoalveolar lavage is invasive and may cause lung injury. Microdialysis (MD) is a method for continuous sampling of extracellular molecules in the immediate surroundings of the catheter. Urea is used as an endogenous marker of dilution in samples collected from the ELF. The aim of this study was to evaluate bronchial MD as a continuous monitor of the ELF.

Methods: Microdialysis catheters were introduced into the right main stem bronchus and into the right subclavian artery of five anesthetized and normoventilated pigs. The flowrate was 2 mul/min and the sampling interval was 60 minutes. Lactate and fluorescein-isothiocyanate-dextran 4 kDa (FD-4) infusions were performed to obtain two levels of steady-state concentrations in blood. Accuracy was defined as [bronchial-MD] divided by [arterial-MD] in percent. Data presented as mean +/- 95 percent confidence interval.

Results: The accuracy of bronchial MD was calculated with and without correction by the arteriobronchial urea gradient. The arteriobronchial lactate gradient was 1.2 +/- 0.1 and FD-4 gradient was 4.0 +/- 1.2. Accuracy of bronchial MD with a continuous lactate infusion was mean 25.5% (range 5.7-59.6%) with a coefficient of variation (CV) of 62.6%. With correction by the arteriobronchial urea gradient accuracy was mean 79.0% (57.3-108.1%) with a CV of 17.0%.

Conclusion: Urea as a marker of catheter functioning enhances bronchial MD and makes it useful for monitoring substantial changes in the composition of the ELF.

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Related in: MedlinePlus

The microdialysis catheter in situ. The picture shows the microdialysis catheter in the distal bronchus. The distal white part is the microdialysis membrane. It is this part of the catheter that is in contact with the epithelial lining fluid and collects molecules by diffusion.
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Figure 1: The microdialysis catheter in situ. The picture shows the microdialysis catheter in the distal bronchus. The distal white part is the microdialysis membrane. It is this part of the catheter that is in contact with the epithelial lining fluid and collects molecules by diffusion.

Mentions: To verify the position of the catheter at the end of the experiment, the microdialysis catheter either was perfused with methylene blue and the bronchial tree dissected or the catheter was left in situ and the bronchial tree dissected (figure 1).


Continuous monitoring of the bronchial epithelial lining fluid by microdialysis.

Tyvold SS, SolligÄrd E, Lyng O, Steinshamn SL, Gunnes S, Aadahl P - Respir. Res. (2007)

The microdialysis catheter in situ. The picture shows the microdialysis catheter in the distal bronchus. The distal white part is the microdialysis membrane. It is this part of the catheter that is in contact with the epithelial lining fluid and collects molecules by diffusion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2169243&req=5

Figure 1: The microdialysis catheter in situ. The picture shows the microdialysis catheter in the distal bronchus. The distal white part is the microdialysis membrane. It is this part of the catheter that is in contact with the epithelial lining fluid and collects molecules by diffusion.
Mentions: To verify the position of the catheter at the end of the experiment, the microdialysis catheter either was perfused with methylene blue and the bronchial tree dissected or the catheter was left in situ and the bronchial tree dissected (figure 1).

Bottom Line: Accuracy was defined as [bronchial-MD] divided by [arterial-MD] in percent.With correction by the arteriobronchial urea gradient accuracy was mean 79.0% (57.3-108.1%) with a CV of 17.0%.Urea as a marker of catheter functioning enhances bronchial MD and makes it useful for monitoring substantial changes in the composition of the ELF.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesia and Intensive Care, St, Olavs Hospital, Trondheim, Norway. stig.s.tyvold@ntnu.no

ABSTRACT

Background: Contents of the epithelial lining fluid (ELF) of the bronchi are of central interest in lung diseases, acute lung injury and pharmacology. The most commonly used technique broncheoalveolar lavage is invasive and may cause lung injury. Microdialysis (MD) is a method for continuous sampling of extracellular molecules in the immediate surroundings of the catheter. Urea is used as an endogenous marker of dilution in samples collected from the ELF. The aim of this study was to evaluate bronchial MD as a continuous monitor of the ELF.

Methods: Microdialysis catheters were introduced into the right main stem bronchus and into the right subclavian artery of five anesthetized and normoventilated pigs. The flowrate was 2 mul/min and the sampling interval was 60 minutes. Lactate and fluorescein-isothiocyanate-dextran 4 kDa (FD-4) infusions were performed to obtain two levels of steady-state concentrations in blood. Accuracy was defined as [bronchial-MD] divided by [arterial-MD] in percent. Data presented as mean +/- 95 percent confidence interval.

Results: The accuracy of bronchial MD was calculated with and without correction by the arteriobronchial urea gradient. The arteriobronchial lactate gradient was 1.2 +/- 0.1 and FD-4 gradient was 4.0 +/- 1.2. Accuracy of bronchial MD with a continuous lactate infusion was mean 25.5% (range 5.7-59.6%) with a coefficient of variation (CV) of 62.6%. With correction by the arteriobronchial urea gradient accuracy was mean 79.0% (57.3-108.1%) with a CV of 17.0%.

Conclusion: Urea as a marker of catheter functioning enhances bronchial MD and makes it useful for monitoring substantial changes in the composition of the ELF.

Show MeSH
Related in: MedlinePlus