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Respiration. 2009;77(3):282-91. doi: 10.1159/000193994. Epub 2009 Jan 16.

Assessment of changes in distribution of lung perfusion by electrical impedance tomography.

Author information

1
Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany. frerichs@anaesthesie.uni-kiel.de

Abstract

BACKGROUND:

Electrical impedance tomography (EIT) is able to detect variations in regional lung electrical impedance associated with changes in both air and blood content and potentially capable of assessing regional ventilation-perfusion relationships. However, regional lung perfusion is difficult to determine because the impedance changes synchronous with the heart rate are of very small amplitude.

OBJECTIVES:

The aim of our study was to determine the redistribution of lung perfusion elicited by one-lung ventilation using EIT with a novel region-of-interest analysis.

METHODS:

Ten patients (65 +/- 9 years, mean age +/- SD) scheduled for elective chest surgery were studied after intubation with a double-lumen endotracheal tube during bilateral and unilateral ventilation of the right and left lungs. EIT data were acquired at a rate of 25 scans/s. Relative impedance changes synchronous with the heart rate were evaluated in the right and left lung regions.

RESULTS:

During bilateral ventilation, the mean right-to-left lung ratio of the sum of heart rate-related impedance changes was 1.12 +/- 0.20, but the ratio significantly changed (0.81 +/- 0.16 and 1.48 +/- 0.37) during unilateral left- and right-lung ventilation with reduced perfusion of the non-ventilated lung. Increased perfusion most likely occurred in the ventilated lung because the impedance values summed over both regions did not change (0.62 +/- 0.23 vs. 0.58 +/- 0.22) compared with bilateral ventilation.

CONCLUSIONS:

Our results indicate that redistribution of regional lung perfusion can be assessed by EIT during one-lung ventilation. The performance of EIT in detecting changes in lung perfusion in even smaller lung regions remains to be established.

PMID:
19147986
DOI:
10.1159/000193994
[Indexed for MEDLINE]

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