Spontaneous breathing with airway pressure release ventilation favors ventilation in dependent lung regions and counters cyclic alveolar collapse in oleic-acid-induced lung injury: a randomized controlled computed tomography trialReportar como inadecuado




Spontaneous breathing with airway pressure release ventilation favors ventilation in dependent lung regions and counters cyclic alveolar collapse in oleic-acid-induced lung injury: a randomized controlled computed tomography trial - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Critical Care

, 9:R780

First Online: 16 November 2005Received: 29 July 2005Accepted: 19 October 2005

Abstract

IntroductionExperimental and clinical studies have shown a reduction in intrapulmonary shunt with spontaneous breathing during airway pressure release ventilation APRV in acute lung injury. This reduction was related to reduced atelectasis and increased aeration. We hypothesized that spontaneous breathing will result in better ventilation and aeration of dependent lung areas and in less cyclic collapse during the tidal breath.

MethodsIn this randomized controlled experimental trial, 22 pigs with oleic-acid-induced lung injury were randomly assigned to receive APRV with or without spontaneous breathing at comparable airway pressures. Four hours after randomization, dynamic computed tomography scans of the lung were obtained in an apical slice and in a juxtadiaphragmatic transverse slice. Analyses of regional attenuation were performed separately in nondependent and dependent halves of the lungs on end-expiratory scans and end-inspiratory scans. Tidal changes were assessed as differences between inspiration and expiration of the mechanical breaths.

ResultsWhereas no differences were observed in the apical slices, spontaneous breathing resulted in improved tidal ventilation of dependent lung regions P < 0.05 and less cyclic collapse P < 0.05 in the juxtadiaphragmatic slices. In addition, with spontaneous breathing, the end-expiratory aeration increased and nonaerated tissue decreased in dependent lung regions close to the diaphragm P < 0.05 for the interaction ventilator mode and lung region.

ConclusionSpontaneous breathing during APRV redistributes ventilation and aeration to dependent, usually well-perfused, lung regions close to the diaphragm, and may thereby contribute to improved arterial oxygenation. Spontaneous breathing also counters cyclic collapse, which is a risk factor for ventilation-associated lung injury.

AbbreviationsALIacute lung injury

APRVairway pressure release ventilation

CTcomputed tomography

EELVend-expiratory lung volume

FiO2fraction of inspired oxygen

HUHounsfield units

PaCO2arterial carbon dioxide tension

PEEPpositive end-expiratory pressure

ROIregion of interest.

Electronic supplementary materialThe online version of this article doi:10.1186-cc3908 contains supplementary material, which is available to authorized users.

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Autor: Hermann Wrigge - Jörg Zinserling - Peter Neumann - Thomas Muders - Anders Magnusson - Christian Putensen - Göran Hedensti

Fuente: https://link.springer.com/







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