Article
Electrical Impedance Tomography (EIT): a non-invasive method for the assessment of ventilation/perfusion changes following lung contusion
Search Medline for
Authors
-
Klemens Horst
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Aachen, Germany
-
Roman Pfeifer
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Aachen, Germany
-
Tim Simon
- Universitätsklinikum Aachen, Klinik für Operative Intensivmedizin und Intermediate Care, Aachen, Germany
-
Susana Aguiar Santos
- Helmholtz-Institut für Biomedizinische Technik RWTH Aachen , Lehrstuhl für Medizinische Informationstechnik , Aachen, Germany
-
Carlos Castelar-Wembers
- Helmholtz-Institut für Biomedizinische Technik RWTH Aachen , Lehrstuhl für Medizinische Informationstechnik , Aachen, Germany
-
Steffen Leonhardt
- Helmholtz-Institut für Biomedizinische Technik RWTH Aachen , Lehrstuhl für Medizinische Informationstechnik , Aachen, Germany
-
Frank Hildebrand
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Aachen, Germany
-
Hans-Christoph Pape
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Aachen, Germany
| Published: | October 10, 2016 |
|---|
Outline
Text
Objectives: Electrical Impedance Tomography (EIT) represents a safe, non-invasive and reliable tool to assess ventilation/perfusion changes. We hypothesized that real-time EIT will help to detect lung contusion in polytrauma. Therefore we set up a porcine model of combined trauma with lung contusion.
Methods: Male pigs (30±3kg) were used. A standardized lung contusion (bolt shot, 9x17 Dynamit Nobel), was combined with a femoral fracture (bolt shot, 9x17 Dynamit Nobel), liver laceration (standardized cut of 4.5x4.5 cm) and controlled hemorrhage (MAP 40±5mmHg) for 90 minutes. Animals were mechanically ventilated and under ICU-monitoring for 72h. EIT measurements of ventilation were performed before as well as 4h, 24h, 48h and 72h after trauma using the EIT Evaluation Kit 2 (EEK2), Dräger AG, Lübeck, Germany. The regional tidal variation (TV) (%) for each of the ROIs (picture 1) was calculated by summing up all the regional ventilation-induced impedance changes. Ventilation parameters as well as blood gas analysis were recorded. At the end of the observation period animals were sacrificed and lungs were assessed macro- as well as microscopically.
Results: EIT detected 1) a regional decrease in mean impedance variation over the affected right lung after trauma and an increase over the intact left lung (right lung: 35.3% (SD 11.3) vs. left lung: 64.7% (SD 11.3), p=0.003) indicating reduced ventilation of the affected, and a compensatory augmented ventilation of the unaffected lung and 2) a pronounced fall in local electrical impedance (24h = 35.6% (SD 16.1), 48h = 41.8% (16.1)) compared with baseline (47.9% (4.4), p=0.045) over the injured lung with a moderate increase over the intact lung during the observation period (24h = 64.4% (SD 16.1), 48h = 58.2% (SD 16.1)) compared with baseline (52.1% (SD 4.4), p=0.045) indicating the development of lung edema in the injured lung with a probable atelectasis formation in the contralateral one.
Conclusion: EIT is a noninvasive method that demonstrated local impairment of pulmonary ventilation and the formation of pulmonary fluid accumulation indicating edema. This technique may become an adjunct tool for the assessment of local pulmonary changes in an ICU setting. Further study is warranted to assess time dependent changes, or other pulmonary disorders.
