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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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Related in: MedlinePlus

Overview of the lactate infusion with two steady states. Data are presented as mean lactate values by arterial microdialysis (solid line) with mean values in steady state (filled triangles), bronchial microdialysis (long dash line) with mean values in steady state (filled circles) and ureacorrected bronchial microdialysis (dash-dot line) with mean values in steady state (open circles). The circles and the triangles represent the time where the microdialysis vials were exchanged for the steady state samples. The gray area is a graphical presentation of the intravenous lactate infusion. During the low steady state the infusion of sodium lactate was gradually increased to maintain an arterial blood lactate of ~5 mmol/L. During the high steady state the infusion of sodium lactate was increased to maintain an arterial blood lactate of ~10 mmol/L.
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Figure 2: Overview of the lactate infusion with two steady states. Data are presented as mean lactate values by arterial microdialysis (solid line) with mean values in steady state (filled triangles), bronchial microdialysis (long dash line) with mean values in steady state (filled circles) and ureacorrected bronchial microdialysis (dash-dot line) with mean values in steady state (open circles). The circles and the triangles represent the time where the microdialysis vials were exchanged for the steady state samples. The gray area is a graphical presentation of the intravenous lactate infusion. During the low steady state the infusion of sodium lactate was gradually increased to maintain an arterial blood lactate of ~5 mmol/L. During the high steady state the infusion of sodium lactate was increased to maintain an arterial blood lactate of ~10 mmol/L.

Mentions: An infusion of sodium lactate ~50% (Merck KGaA, Darmstadt, Germany) was adjusted to an arterial blood lactate concentration of ~5 mmol/l for 120 minutes. Thereafter, the infusion rate was increased to an arterial blood lactate concentration of ~10 mmol/l (figure 2). Arterial blood was collected every 15 minutes throughout the experiment to establish a steady-state of lactate and PaCO2 (ABL700, Radiometer Copenhagen, Denmark).


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)

Overview of the lactate infusion with two steady states. Data are presented as mean lactate values by arterial microdialysis (solid line) with mean values in steady state (filled triangles), bronchial microdialysis (long dash line) with mean values in steady state (filled circles) and ureacorrected bronchial microdialysis (dash-dot line) with mean values in steady state (open circles). The circles and the triangles represent the time where the microdialysis vials were exchanged for the steady state samples. The gray area is a graphical presentation of the intravenous lactate infusion. During the low steady state the infusion of sodium lactate was gradually increased to maintain an arterial blood lactate of ~5 mmol/L. During the high steady state the infusion of sodium lactate was increased to maintain an arterial blood lactate of ~10 mmol/L.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Overview of the lactate infusion with two steady states. Data are presented as mean lactate values by arterial microdialysis (solid line) with mean values in steady state (filled triangles), bronchial microdialysis (long dash line) with mean values in steady state (filled circles) and ureacorrected bronchial microdialysis (dash-dot line) with mean values in steady state (open circles). The circles and the triangles represent the time where the microdialysis vials were exchanged for the steady state samples. The gray area is a graphical presentation of the intravenous lactate infusion. During the low steady state the infusion of sodium lactate was gradually increased to maintain an arterial blood lactate of ~5 mmol/L. During the high steady state the infusion of sodium lactate was increased to maintain an arterial blood lactate of ~10 mmol/L.
Mentions: An infusion of sodium lactate ~50% (Merck KGaA, Darmstadt, Germany) was adjusted to an arterial blood lactate concentration of ~5 mmol/l for 120 minutes. Thereafter, the infusion rate was increased to an arterial blood lactate concentration of ~10 mmol/l (figure 2). Arterial blood was collected every 15 minutes throughout the experiment to establish a steady-state of lactate and PaCO2 (ABL700, Radiometer Copenhagen, Denmark).

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