title: Regional lung perfusion estimated by electrical impedance tomography in a piglet model of lung collapse.
abstract: The assessment of the regional match between alveolar ventilation and perfusion in critically ill patients requires simultaneous measurements of both parameters. Ideally, assessment of lung perfusion should be performed in real-time with an imaging technology that provides, through fast acquisition of sequential images, information about the regional dynamics or regional kinetics of an appropriate tracer. We present a novel electrical impedance tomography (EIT)-based method that quantitatively estimates regional lung perfusion based on first-pass kinetics of a bolus of hypertonic saline contrast. Pulmonary blood flow was measured in six piglets during control and unilateral or bilateral lung collapse conditions. The first-pass kinetics method showed good agreement with the estimates obtained by single-photon-emission computerized tomography (SPECT). The mean difference (SPECT minus EIT) between fractional blood flow to lung areas suffering atelectasis was -0.6%, with a SD of 2.9%. This method outperformed the estimates of lung perfusion based on impedance pulsatility. In conclusion, we describe a novel method based on EIT for estimating regional lung perfusion at the bedside. In both healthy and injured lung conditions, the distribution of pulmonary blood flow as assessed by EIT agreed well with the one obtained by SPECT. The method proposed in this study has the potential to contribute to a better understanding of the behavior of regional perfusion under different lung and therapeutic conditions.
authors.affiliation: Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Uppsala University, Uppsala, Sweden. joao.batista_borges@medsci.uu.se
authors.forename: João Batista
authors.initials: JB
authors.lastname: Borges
authors.forename: Fernando
authors.initials: F
authors.lastname: Suarez-Sipmann
authors.forename: Stephan H
authors.initials: SH
authors.lastname: Bohm
authors.forename: Gerardo
authors.initials: G
authors.lastname: Tusman
authors.forename: Alexandre
authors.initials: A
authors.lastname: Melo
authors.forename: Enn
authors.initials: E
authors.lastname: Maripuu
authors.forename: Mattias
authors.initials: M
authors.lastname: Sandström
authors.forename: Marcelo
authors.initials: M
authors.lastname: Park
authors.forename: Eduardo L V
authors.initials: EL
authors.lastname: Costa
authors.forename: Göran
authors.initials: G
authors.lastname: Hedenstierna
authors.forename: Marcelo
authors.initials: M
authors.lastname: Amato
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004195:Disease Models, Animal; D017097:Electric Impedance; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology*; D010477:Perfusion / Q000379:methods*; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013552:Swine; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*