Báo cáo y học: Positive end-expiratory pressure at minimal respiratory elastance represents the best compromise between mechanical stress and lung aeration in oleic acid induced lung injury

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: Positive end-expiratory pressure at minimal respiratory elastance represents the best compromise between mechanical stress and lung aeration in oleic acid induced lung injury...
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Báo cáo y học: "Positive end-expiratory pressure at minimal respiratory elastance represents the best compromise between mechanical stress and lung aeration in oleic acid induced lung injury" Available online http://ccforum.com/content/11/4/R86Research Open AccessVol 11 No 4Positive end-expiratory pressure at minimal respiratory elastancerepresents the best compromise between mechanical stress andlung aeration in oleic acid induced lung injuryAlysson Roncally S Carvalho1, Frederico C Jandre1, Alexandre V Pino1, Fernando A Bozza2,Jorge Salluh3, Rosana Rodrigues4, Fabio O Ascoli2 and Antonio Giannella-Neto1Biomedical Engineering Program, COPPE, Federal University of Rio de Janeiro, Av. Horácio Macedo, CT Bloco H-327, 2030, 21941-914, Rio deJaneiro, Brazil2Fundação Oswaldo Cruz, Instituto de Pesquisa Clinica Evandro Chagas e Laboratório de Imunofarmacologia, IOC, Av Brasil, 4365, Manguinhos,21045-900 Rio de Janeiro, Brazil3National Institute of Cancer-1, ICU, Praça Cruz Vermelha, 20230-130 Rio de Janeiro, Brazil4Radiodiagnostic Service, Clementino Fraga Filho Hospital, Federal University of Rio de Janeiro, R Professor Rodolpho Paulo Rocco, 255, 21-941-913 Rio de Janeiro, BrazilCorresponding author: Antonio Giannella-Neto, agn@peb.ufrj.brReceived: 5 Jan 2007 Revisions requested: 20 Feb 2007 Revisions received: 3 Apr 2007 Accepted: 9 Aug 2007 Published: 9 Aug 2007Critical Care 2007, 11:R86 (doi:10.1186/cc6093)This article is online at: http://ccforum.com/content/11/4/R86© 2007 Carvalho et al.; licensee BioMed Central Ltd.This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.AbstractIntroduction Protective ventilatory strategies have been applied Results Progressive reduction in PEEP from 26 cmH2O to theto prevent ventilator-induced lung injury in patients with acute PEEP at which the minimum Ers was observed improved poorlylung injury (ALI). However, adjustment of positive end-expiratory aerated areas, with a proportional reduction in hyperinflatedpressure (PEEP) to avoid alveolar de-recruitment and areas. Also, the distribution of normally aerated areas remainedhyperinflation remains difficult. An alternative is to set the PEEP steady over this interval, with no changes in non-aerated areas.based on minimizing respiratory system elastance (Ers) by The PEEP at which minimal Ers occurred corresponded to thetitrating PEEP. In the present study we evaluate the distribution greatest amount of normally aerated areas, with lesserof lung aeration (assessed using computed tomography hyperinflated, and poorly and non-aerated areas. Levels of PEEPscanning) and the behaviour of Ers in a porcine model of ALI, below that at which minimal Ers was observed increased poorlyduring a descending PEEP titration manoeuvre with a protective and non-aerated areas, with concomitant reductions in normallylow tidal volume. inflated and hyperinflated areas.Methods PEEP titration (from 26 to 0 cmH2O, with a tidalvolume of 6 to 7 ml/kg) was performed, following a recruitmentmanoeuvre. At each PEEP, helical computed tomography scans Conclusion The PEEP at which minimal Ers occurred, obtainedof juxta-diaphragmatic parts of the lower lobes were obtained by descending PEEP titration with a protective low tidal volume,during end-expiratory and end-inspiratory pauses in six piglets corresponded to the greatest amount of normally aerated areas,with ALI induced by oleic acid. The distribution of the lung with lesser collapsed and hyperinflated areas. The institution ofcompartments (hyperinflated, normally aerated, poorly aerated high levels of PEEP reduced poorly aerated areas but enlargedand non-aerated areas) was determined and the Ers was hyperinflated ones. Reduction in PEEP consistently enhancedestimated on a breath-by-breath basis from the equation of poorly or non-aerated areas as well as tidal re-aeration. Hence,motion of the respiratory system using the least-squares monitoring respiratory mechanics during a PEEP titrationmethod. procedure may be a useful adjunct to optimize lung aeration.Introduction support modality in patients suffering from acute lung injuryMechanical ventilation has become the most important life (ALI) [1]. However, use of high tidal volumes (VTs) andALI = acute lung injury; CT = computed tomography; Ers = elastance of the respiratory system; PEEP = positive end-expiratory pressure; PEEPErs =PEEP at which the minimum Ers was observed; Rrs = resistance of the respiratory system; VT = tidal volume; ZEEP = zero end-expiratory pressure. Page 1 of 13 (page number not for citation purposes)Critical Care Vol 11 No 4 Carvalho et al. Materials and methodsinappropriate levels of positive end ...