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Estimation of changes in cyclic lung strain by electrical impedance tomography: Proof‐of‐concept study
Author(s) -
Cornejo Rodrigo,
Iturrieta Pablo,
Olegário Tayran M. M.,
Kajiyama Carolina,
Arellano Daniel,
Guiñez Dannette,
Cerda María A.,
Brito Roberto,
Gajardo Abraham I. J.,
Lazo Marioli,
López Lorena,
Morais Caio C. A.,
González Sedric,
Zavala Miguel,
Rojas Verónica,
Medel Juan N.,
Hurtado Daniel E.,
Bruhn Alejandro,
Ramos Cristobal,
Estuardo Nivia
Publication year - 2021
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.13723
Subject(s) - electrical impedance tomography , medicine , expiration , mechanical ventilation , strain (injury) , lung , ventilation (architecture) , tomography , nuclear medicine , cardiology , radiology , respiratory system , mechanical engineering , engineering
Rationale Cyclic strain may be a determinant of ventilator‐induced lung injury. The standard for strain assessment is the computed tomography (CT), which does not allow continuous monitoring and exposes to radiation. Electrical impedance tomography (EIT) is able to monitor changes in regional lung ventilation. In addition, there is a correlation between mechanical deformation of materials and detectable changes in its electrical impedance, making EIT a potential surrogate for cyclic lung strain measured by CT (Strain CT ). Objectives To compare the global Strain CT with the change in electrical impedance (Δ Z ). Methods Acute respiratory distress syndrome patients under mechanical ventilation ( V T 6 mL/kg ideal body weight with positive end‐expiratory pressure 5 [PEEP 5] and best PEEP according to EIT) underwent whole‐lung CT at end‐inspiration and end‐expiration. Biomechanical analysis was used to construct 3D maps and determine Strain CT at different levels of PEEP. CT and EIT acquisitions were performed simultaneously. Multilevel analysis was employed to determine the causal association between Strain CT and Δ Z . Linear regression models were used to predict the change in lung Strain CT between different PEEP levels based on the change in Δ Z . Main results Strain CT was positively and independently associated with Δ Z at global level ( P < .01). Furthermore, the change in Strain CT (between PEEP 5 and Best PEEP) was accurately predicted by the change in Δ Z ( R 2 0.855, P < .001 at global level) with a high agreement between predicted and measured Strain CT . Conclusions The change in electrical impedance may provide a noninvasive assessment of global cyclic strain, without radiation at bedside.