The online version of this article (doi:10.1186/cc10354) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
IB and CP carried out the data acquisition, data processing, data analysis and statistical analysis and participated in drafting the manuscript. ME participated in the data acquisition, data processing and statistical analysis. DG and JB participated in data acquisition and drafting the manuscript. All authors read and approved the final version of the manuscript.
Computed tomography of the lung has shown that ventilation shifts from dependent to nondependent lung regions. In this study, we investigated whether, at the bedside, electrical impedance tomography (EIT) at the cranial and caudal thoracic levels can be used to visualize changes in ventilation distribution during a decremental positive end-expiratory pressure (PEEP) trial and the relation of these changes to global compliance in mechanically ventilated patients.
Ventilation distribution was calculated on the basis of EIT results from 12 mechanically ventilated patients after cardiac surgery at a cardiothoracic ICU. Measurements were taken at four PEEP levels (15, 10, 5 and 0 cm H2O) at both the cranial and caudal lung levels, which were divided into four ventral-to-dorsal regions. Regional compliance was calculated using impedance and driving pressure data.
We found that tidal impedance variation divided by tidal volume significantly decreased on caudal EIT slices, whereas this measurement increased on the cranial EIT slices. The dorsal-to-ventral impedance distribution, expressed according to the center of gravity index, decreased during the decremental PEEP trial at both EIT levels. Optimal regional compliance differed at different PEEP levels: 10 and 5 cm H2O at the cranial level and 15 and 10 cm H2O at the caudal level for the dependent and nondependent lung regions, respectively.
At the bedside, EIT measured at two thoracic levels showed different behavior between the caudal and cranial lung levels during a decremental PEEP trial. These results indicate that there is probably no single optimal PEEP level for all lung regions.
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Bikker IG, Leonhardt S, Reis MD, Bakker J, Gommers D: Bedside measurement of changes in lung impedance to monitor alveolar ventilation in dependent and non-dependent parts by electrical impedance tomography during a positive end-expiratory pressure trial in mechanically ventilated intensive care unit patients. Crit Care 2010, 14: R100. 10.1186/cc9036 PubMedPubMedCentralCrossRef
Victorino JA, Borges JB, Okamoto VN, Matos GF, Tucci MR, Caramez MP, Tanaka H, Sipmann FS, Santos DC, Barbas CS, Carvalho CR, Amato MB: Imbalances in regional lung ventilation: a validation study on electrical impedance tomography. Am J Respir Crit Care Med 2004, 169: 791-800. 10.1164/rccm.200301-133OC PubMedCrossRef
Xu G, Wang R, Zhang S, Yang S, Justin GA, Sun M, Yan W: A 128-electrode three dimensional electrical impedance tomography system. Conf Proc IEEE Eng Med Biol Soc 2007, 2007: 4386-4389. PubMed
- Electrical impedance tomography measured at two thoracic levels can visualize the ventilation distribution changes at the bedside during a decremental positive end-expiratory lung pressure trial
Ido G Bikker
- BioMed Central
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