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Continuous monitoring of the bronchial epithelial lining fluid by microdialysis.

Tyvold SS, Solligård 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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XY-plot of bronchial and corrected bronchial microdialysis data against arterial microdialysis data of lactate and fluorescein isothiocyanate dextran 4000 Da. All five pigs are represented; number one closed circles and line, number two open circles and dotted line, number three closed triangles and medium dashed line, number four open triangles and dash-dot-dot line, and number five closed squares and long dashed line. Plot A and B show arterial lactate along the X-axis and bronchial (R2 0.82 ± 0.18) and ureacorrected bronchial lactate (R2 0.91 ± 0.11) along the Y-axis respectively. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial lactate XY-plots showed significant difference (p < 0.05). Plot C and D show arterial fluorescein isothiocyanate dextran 4000 Da (FD-4) along the X-axis and bronchial (R2 0.53 ± 0.38) and ureacorrected bronchial FD-4 (R2 0.72 ± 0.34) along the Y-axis. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial FD-4 XY-plots was not significant.
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Figure 7: XY-plot of bronchial and corrected bronchial microdialysis data against arterial microdialysis data of lactate and fluorescein isothiocyanate dextran 4000 Da. All five pigs are represented; number one closed circles and line, number two open circles and dotted line, number three closed triangles and medium dashed line, number four open triangles and dash-dot-dot line, and number five closed squares and long dashed line. Plot A and B show arterial lactate along the X-axis and bronchial (R2 0.82 ± 0.18) and ureacorrected bronchial lactate (R2 0.91 ± 0.11) along the Y-axis respectively. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial lactate XY-plots showed significant difference (p < 0.05). Plot C and D show arterial fluorescein isothiocyanate dextran 4000 Da (FD-4) along the X-axis and bronchial (R2 0.53 ± 0.38) and ureacorrected bronchial FD-4 (R2 0.72 ± 0.34) along the Y-axis. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial FD-4 XY-plots was not significant.

Mentions: To evaluate bronchial microdialysis as a tool of continuous monitoring all pigs are presented in XY-plots with individual values and correlation lines (figure 7). There was a significant improvement in the correlation between urea-corrected bronchial and arterial lactate values versus bronchial and arterial lactate values by paired t-test. For fluorescein isothiocyanate, the improvement was only a tendency and did not reach significance.


Continuous monitoring of the bronchial epithelial lining fluid by microdialysis.

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

XY-plot of bronchial and corrected bronchial microdialysis data against arterial microdialysis data of lactate and fluorescein isothiocyanate dextran 4000 Da. All five pigs are represented; number one closed circles and line, number two open circles and dotted line, number three closed triangles and medium dashed line, number four open triangles and dash-dot-dot line, and number five closed squares and long dashed line. Plot A and B show arterial lactate along the X-axis and bronchial (R2 0.82 ± 0.18) and ureacorrected bronchial lactate (R2 0.91 ± 0.11) along the Y-axis respectively. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial lactate XY-plots showed significant difference (p < 0.05). Plot C and D show arterial fluorescein isothiocyanate dextran 4000 Da (FD-4) along the X-axis and bronchial (R2 0.53 ± 0.38) and ureacorrected bronchial FD-4 (R2 0.72 ± 0.34) along the Y-axis. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial FD-4 XY-plots was not significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 7: XY-plot of bronchial and corrected bronchial microdialysis data against arterial microdialysis data of lactate and fluorescein isothiocyanate dextran 4000 Da. All five pigs are represented; number one closed circles and line, number two open circles and dotted line, number three closed triangles and medium dashed line, number four open triangles and dash-dot-dot line, and number five closed squares and long dashed line. Plot A and B show arterial lactate along the X-axis and bronchial (R2 0.82 ± 0.18) and ureacorrected bronchial lactate (R2 0.91 ± 0.11) along the Y-axis respectively. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial lactate XY-plots showed significant difference (p < 0.05). Plot C and D show arterial fluorescein isothiocyanate dextran 4000 Da (FD-4) along the X-axis and bronchial (R2 0.53 ± 0.38) and ureacorrected bronchial FD-4 (R2 0.72 ± 0.34) along the Y-axis. Paired t-test of R2 for the individual bronchial and ureacorrected bronchial FD-4 XY-plots was not significant.
Mentions: To evaluate bronchial microdialysis as a tool of continuous monitoring all pigs are presented in XY-plots with individual values and correlation lines (figure 7). There was a significant improvement in the correlation between urea-corrected bronchial and arterial lactate values versus bronchial and arterial lactate values by paired t-test. For fluorescein isothiocyanate, the improvement was only a tendency and did not reach significance.

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