Respiratory Research (Jul 2024)

First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography

  • Vinicius Torsani,
  • Paulo Francisco Guerreiro Cardoso,
  • João Batista Borges,
  • Susimeire Gomes,
  • Henrique Takachi Moriya,
  • Andrea Fonseca da Cruz,
  • Roberta Ribeiro de Santis Santiago,
  • Cristopher Kengo Nagao,
  • Mariana Fernandes Fitipaldi,
  • Marcelo do Amaral Beraldo,
  • Marcus Henrique Victor Junior,
  • Mikuláš Mlček,
  • Paulo Manuel Pego-Fernandes,
  • Marcelo Britto Passos Amato

DOI
https://doi.org/10.1186/s12931-024-02877-0
Journal volume & issue
Vol. 25, no. 1
pp. 1 – 14

Abstract

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Abstract Background Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV. Methods Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces. Results Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2. Conclusions EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place. Trial registration Not applicable.

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