Effect of Prone Position on Regional Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

Richter, Torsten; Bellani, Giacomo; Harris, R. Scott; Melo, Marcos F. Vidal; Winkler, Tilo; Venegas, José G.; Musch, Guido

doi:10.1164/rccm.200501-004oc

Cited by 178 publications

(156 citation statements)

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“…Animal studies have demonstrated improved oxygenation and ventilation perfusion ratios, along with restoring aeration, decreasing shunt, and preserving perfusion 1,9,15 . In addition, prone positioning has been shown to eliminate compression of the lungs by the heart 16 .…”

Section: Discussionmentioning

confidence: 99%

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Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats

et al. 2008

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Purpose:To compare the effectiveness of mechanical ventilation of supine versus prone position in hydrochloric acid (HCl)-induced lung dysfunction. Methods: Twenty, adult, male, Wistar-EPM-1 rats were anesthetized and randomly grouped (n=5 animals per group) as follows: CS-MV (mechanical ventilation in supine position); CP-MV (mechanical ventilation in prone position); bilateral instillation of HCl and mechanical ventilation in supine position (HCl+S); and bilateral instillation of HCl and mechanical ventilation in prone position (HCl+P). All groups were ventilated for 180 minutes. The blood partial pressures of oxygen and carbon dioxide were measured in the time points 0 (zero; 10 minutes before lung injury for stabilization), and at the end of times acid injury, 60, 120 and 180 minutes of mechanical ventilation. At the end of experiment the animals were euthanized, and bronchoalveolar lavages (BALs) were taken to determine the contents of total proteins, inflammatory mediators, and lungs wet-to-dry ratios. Results: In the HCl+P group the partial pressure of oxygen increased when compared with HCl+S (128.0±2.9 mmHg and 111.0±6.7 mmHg, respectively) within 60 minutes. TNF-α levels in BAL do not differ significantly in the HCl+P group (516.0±5.9 pg/mL), and the HCl+S (513.0±10.6 pg/mL). Conclusion:The use of prone position improved oxygenation, but did not reduce TNF-α in BAL upon lung dysfunction induced by HCl. Key words: Lung. Respiration, Artificial. Oxygenation. Inflammation Mediators. Rats. RESUMO Objetivo:Comparar os efeitos da ventilação mecânica em posição prona versus supina na disfunção pulmonar induzida por ácido clorídrico (HCl). Métodos: Vinte ratos, adultos, Wistar-EPM-1 foram anestesiados e distribuídos aleatoriamente em grupos (n=5 animais por grupo): CS-MV (controle, ventilado mecanicamente em posição supina); CP-MV (controle, ventilado mecanicamente em posição prona); instilação bilateral de HCl e ventilação mecânica em posição supina (HCl+S) ou ventilação em posição prona (HCl+P). Todos os grupos foram submetidos a ventilação mecânica por 180 minutos. As pressões parciais de oxigênio e dióxido de carbono no sangue arterial foram mensuradas nos tempos Injúria ácida (10 minutos após instilação de HCl), e ao final de cada período após lesão por HCl, 60, 120 e 180 minutos sob ventilação mecânica. Ao final do experimento os animais foram eutanasiados, os pulmões retirados para avaliação do peso úmido em relação ao peso seco do pulmão direito e realizamos o lavado broncoalveolar (BAL) para determinação de proteínas totais e o mediador inflamatório TNF-α. Resultados: No grupo HCl+P a pressão parcial de oxigênio, no tempo de 60 minutos, aumentou quando comparada com o grupo HCl+S (128.0±2.9 e 111.0±6.7 mmHg, respectivamente). Os níveis de TNF-α no lavado broncoalveolar não diferiram de maneira estatisticamente significante quando comparamos os grupos HCl+S (513.0±10.6 pg/mL) versus HCl+P (516.0±5.9 pg/mL). Conclusão: O uso da posição prona melhora a oxigenação, mas não reduz os níveis de BAL ...

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Section: Discussionmentioning

confidence: 99%

“…The use of prone ventilation has been shown to improve aeration and decrease alveolar shunt in an animal model 9 . Many clinical and experimental studies have since been carried out, but the mechanism responsible for the improvement remains highly controversial 4,10 .…”

Section: Introductionmentioning

confidence: 99%

Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats

et al. 2008

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“…When patients are placed in the prone position, the chest wall compliance decreases, and the P TP is redistributed from dorsal to ventral and, as a consequence, there is a recruitment of pulmonary dorsal regions, which directly reflects the improvement in patient's oxygenation [10][11][12] . By promoting a more balanced ventilation associated with recruitment, the prone position also results in a better distribution of blood flow 13 , preventing its inappropriate redirection from hyperinflated areas to the collapsed ones in response to increased average airway pressure and positive end-expiratory pressure (PEEP) 14,15 . In addition to direct effects, studies show that the ventilation in prone protects from, or at least slows the development of, injuries associated with mechanical ventilation 16 .…”

Section: Methods Methods Methods Methodsmentioning

confidence: 99%

Pulmonar recruitment in acute respiratory distress syndrome. What is the best strategy?

Santos

Samary

Júnior

et al. 2015

Rev. Col. Bras. Cir.

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Supporting patients with acute respiratory distress syndrome (ARDS), using a protective mechanical ventilation strategy characterized by low tidal volume and limitation of positive end-expiratory pressure (PEEP) is a standard practice in the intensive care unit. However, these strategies can promote lung de-recruitment, leading to the cyclic closing and reopening of collapsed alveoli and small airways. Recruitment maneuvers (RM) can be used to augment other methods, like positive end-expiratory pressure and positioning, to improve aerated lung volume. Clinical practice varies widely, and the optimal method and patient selection for recruitment maneuvers have not been determined, considerable uncertainty remaining regarding the appropriateness of RM. This review aims to discuss recent findings about the available types of RM, and compare the effectiveness, indications and adverse effects among them, as well as their impact on morbidity and mortality in ARDS patients. Recent developments include experimental and clinical evidence that a stepwise extended recruitment maneuver may cause an improvement in aerated lung volume and decrease the biological impact seen with the traditionally used sustained inflation, with less adverse effects. Prone positioning can reduce mortality in severe ARDS patients and may be an useful adjunct to recruitment maneuvers and advanced ventilatory strategies, such noisy ventilation and BIVENT, which have been useful in providing lung recruitment.

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“…Th e reduction or delay in the development of VILI in the prone position can be explained by diff erent mechanisms: (a) A more homogeneous distribution of transpulmonary pressure gradient due to changes in the lung-thorax interactions and direct transmission of the weight of the abdominal contents and heart [22], yielding a redistribution of ventilation; (b) increased endexpiratory lung volume resulting in a reduction in stress and strain [25]; and (c) changes in regional perfusion and/or blood volume [26]. In a paraquat model of ALI, the prone position was associated with a better perfusion in ventral and dorsal regions, a more homogeneous distribution of alveolar aeration which reduced lung mechanical changes and increased end expiratory lung volume and oxygenation [27].…”

Section: Patient Positioningmentioning

confidence: 99%

“…Some authors have reported that in healthy [23], as well as in lung-injured animals [24], mechanical ventilation leading to lung overdistension and cyclic collapse/reopening was associated with less extensive histological change in dorsal regions in the prone, as compared to the supine position. Although the claim that body position aff ects the distribution of lung injury has been challenged, the development of VILI due to excessively high V T seems to be delayed during prone compared to supine positioning [25].Th e reduction or delay in the development of VILI in the prone position can be explained by diff erent mechanisms: (a) A more homogeneous distribution of transpulmonary pressure gradient due to changes in the lung-thorax interactions and direct transmission of the weight of the abdominal contents and heart [22], yielding a redistribution of ventilation; (b) increased endexpiratory lung volume resulting in a reduction in stress and strain [25]; and (c) changes in regional perfusion and/or blood volume [26]. In a paraquat model of ALI, the prone position was associated with a better perfusion in ventral and dorsal regions, a more homogeneous distribution of alveolar aeration which reduced lung mechanical changes and increased end expiratory lung volume and oxygenation [27].…”

mentioning

confidence: 99%

New and Conventional Strategies for Lung Recruitment in Acute Respiratory Distress Syndrome

Pelosi¹,

Abreu²,

Rocco³

2010

Intensive Care Medicine

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This article is one of ten reviews selected from the Yearbook of Intensive Care and Emergency Medicine 2010 (Springer Verlag) and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum/series/yearbook. Further information about the Yearbook of Intensive Care and Emergency Medicine is available from http://www.springer.com/series/2855. Pelosi et al. Critical Care 2010, 14:210 http://ccforum.com/content/14/2/210 © Springer-Verlag Berlin Heidelberg 2010. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. recruitment maneuvers may also contribute to VILI [11,12], with translocation of pulmonary bacteria [13] and cytokines into the systemic circulation [14]. Furthermore, since recruitment maneuvers increase mean thoracic pressure, they may lead to a reduction in venous return with impairment of cardiac output [15]. R E V I E WVarious factors may infl uence the response to a recruitment maneuver, namely: 1) Th e nature and extent of lung injury, and 2) patient positioning. Nature and extent of lung injuryTh e nature of the underlying injury can aff ect the response to a recruitment maneuver. In direct (pulmonary) lung injury, the primary structure damaged is the alveolar epithelium resulting in alveolar fi lling by edema, fi brin, and neutrophilic aggregates. In indirect (extrapulmonary) lung injury, infl ammatory mediators are released from extrapulmonary foci into the systemic circulation leading to microvessel congestion and interstitial edema with relative sparing of intra-alveolar spaces [16]. Th erefore, recruitment maneuvers should be more eff ective to open atelectatic lung regions in indirect compared to direct lung injury. Based on this hypothesis, Kloot et al. [17] investigated the eff ects of recruitment maneuvers on gas exchange and lung volumes in three experimental models of ALI: Saline lavage or surfactant depletion, oleic acid, and pneumonia, and observed improvement in oxygenation only in ALI induced by surfactant depletion. Riva et al. [18] compared the eff ects of a recruitment maneuver in models of pulmonary and extrapulmonary ALI, induced by intratracheal and intraperitoneal instillation of Escherichia coli lipo polysaccharide, with similar transpulmonary pressures. Th ey found that the recruitment maneuver was more eff ective for opening collapsed alveoli in extrapulmonary compared to pulmonary ALI, improving lung mechanics and oxygenation with limited damage to alveolar epithelium. Using electrical imp...

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Effect of Prone Position on Regional Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

Cited by 178 publications

References 40 publications

Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats

Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats

Pulmonar recruitment in acute respiratory distress syndrome. What is the best strategy?

New and Conventional Strategies for Lung Recruitment in Acute Respiratory Distress Syndrome

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