%0 Journal Article
%T Functional respiratory imaging, regional strain, and expiratory time constants at three levels of positive end expiratory pressure in an ex£¿vivo pig model
%A A. William Sheel
%A Cedric Van Holsbeke
%A Donald E. G. Griesdale
%A Francisca Ferreira
%A Harvey O. Coxson
%A John Mayo
%A Miranda Kirby
%A Mypinder Sekhon
%A Paolo B. Dominelli
%A Rachel Lipson
%A William R. Henderson
%A Wim Vos
%A Yannick Molgat©\Seon
%J Archive of "Physiological Reports".
%D 2016
%R 10.14814/phy2.13059
%X Heterogeneity in regional end expiratory lung volume (EELV) may lead to variations in regional strain (¦Å). High ¦Å levels have been associated with ventilator©\associated lung injury (VALI). While both whole lung and regional EELV may be affected by changes in positive end©\expiratory pressure (PEEP), regional variations are not revealed by conventional respiratory system measurements. Differential rates of deflation of adjacent lung units due to regional variation in expiratory time constants (¦Ó E) may create localized regions of ¦Å that are significantly greater than implied by whole lung measures. We used functional respiratory imaging (FRI) in an ex vivo porcine lung model to: (i) demonstrate that computed tomography (CT)©\based imaging studies can be used to assess global and regional values of ¦Å and ¦Ó E and, (ii) demonstrate that the manipulation of PEEP will cause measurable changes in total and regional ¦Å and ¦Ó E values. Our study provides three insights into lung mechanics. First, image©\based measurements reveal egional variation that cannot be detected by traditional methods such as spirometry. Second, the manipulation of PEEP causes global and regional changes in R, E, ¦Å and ¦Ó E values. Finally, regional ¦Å and ¦Ó E were correlated in several lobes, suggesting the possibility that regional ¦Ó E could be used as a surrogate marker for regional ¦Å
%K Positive end©\expiratory pressure
%K strain
%K time constant
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357821/