Assessment of regional ventilation distribution: comparison of vibration response imaging (VRI) with electrical impedance tomography (EIT)

Chang Shi; Stefan Boehme; Alexander H Bentley; Erik K Hartmann; Klaus U Klein; Marc Bodenstein; James E Baumgardner; Matthias David; Roman Ullrich; Klaus Markstaller

doi:10.1371/journal.pone.0086638

Assessment of regional ventilation distribution: comparison of vibration response imaging (VRI) with electrical impedance tomography (EIT)

PLoS One. 2014 Jan 27;9(1):e86638. doi: 10.1371/journal.pone.0086638. eCollection 2014.

Affiliations

¹ Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany ; Beijing Institute of Pharmacology and Toxicology, National Beijing Center for Drug Safety Evaluation and Research, Beijing, China.
² Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany ; Department of Anaesthesia, General Intensive Care and Pain Management, Medical University of Vienna, Vienna, Austria.
³ Department of Anaesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany.
⁴ Oscillogy LLC, Folsom, Pennsylvania, United States of America.
⁵ Department of Anaesthesia, General Intensive Care and Pain Management, Medical University of Vienna, Vienna, Austria.

Abstract

Background: Vibration response imaging (VRI) is a bedside technology to monitor ventilation by detecting lung sound vibrations. It is currently unknown whether VRI is able to accurately monitor the local distribution of ventilation within the lungs. We therefore compared VRI to electrical impedance tomography (EIT), an established technique used for the assessment of regional ventilation.

Methodology/principal findings: Simultaneous EIT and VRI measurements were performed in the healthy and injured lungs (ALI; induced by saline lavage) at different PEEP levels (0, 5, 10, 15 mbar) in nine piglets. Vibration energy amplitude (VEA) by VRI, and amplitudes of relative impedance changes (rel.ΔZ) by EIT, were evaluated in seven regions of interest (ROIs). To assess the distribution of tidal volume (VT) by VRI and EIT, absolute values were normalized to the VT obtained by simultaneous spirometry measurements. Redistribution of ventilation by ALI and PEEP was detected by VRI and EIT. The linear correlation between pooled VT by VEA and rel.ΔZ was R(2) = 0.96. Bland-Altman analysis showed a bias of -1.07±24.71 ml and limits of agreement of -49.05 to +47.36 ml. Within the different ROIs, correlations of VT-distribution by EIT and VRI ranged between R(2) values of 0.29 and 0.96. ALI and PEEP did not alter the agreement of VT between VRI and EIT.

Conclusions/significance: Measurements of regional ventilation distribution by VRI are comparable to those obtained by EIT.

Publication types

Comparative Study
Evaluation Study
Research Support, Non-U.S. Gov't

MeSH terms

Analysis of Variance
Animals
Diagnostic Imaging / methods*
Electric Impedance
Models, Statistical
Pulmonary Ventilation / physiology*
Spirometry
Swine
Tomography / methods*
Vibration*

Grants and funding

The study was funded by German Research Foundation grant No. DFG PAK 415; Ma 2398/6-1, Ma 2398/7-1 and in part by G.E. Healthcare Inc., Milwaukee, USA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.