Effects of prone position and positive end-expiratory pressure on lung perfusion and ventilation. Export

@article{citeulike:2967266, abstract = {OBJECTIVES:: Prone positioning is frequently used during acute respiratory distress syndrome. However, mechanisms by which it improves oxygenation are poorly understood, as well as its interaction with positive end-expiratory pressure. This study was conducted to decipher the respective effects of positive end-expiratory pressure and posture during lung injury on regional lung ventilation, perfusion and recruitment assessed by positron emission tomography. DESIGN:: Experimental study. SETTING:: Research laboratory of a university hospital. SUBJECTS:: Six female piglets. INTERVENTIONS:: After oleic acid-induced lung injury, all animals were studied in supine and prone position at both positive end-expiratory pressure 0 and positive end-expiratory pressure 10 cm H2O. MEASUREMENTS AND MAIN RESULTS:: In each experimental condition, regional lung perfusion and ventilation were assessed with positron emission tomograph using intravenous O-labeled water and inhaled nitrogen-13. Nonaerated lung weight was assessed with positron emission tomograph, and alveolar recruitment was defined as the difference of nonaerated lung weight between conditions. Positive end-expiratory pressure was associated with significant alveolar recruitment (130 +/- 85 and 65 +/- 29 g of lung in supine and prone position, respectively [p < 0.05 vs. 0]), whereas recruitment induced by posture was not statistically significant (77 +/- 97 g with positive end-expiratory pressure 0 and 13 +/- 19 g with positive end-expiratory pressure 10 [p > 0.05 vs. 0]). Regardless the posture, positive end-expiratory pressure redistributed both perfusion and ventilation toward dependent regions. Recruitment by positive end-expiratory pressure was restricted to dorsal regions in supine position, but extended diffusely along the ventral-to-dorsal dimension in prone position. Prone position was associated with recruitment in dorsal regions with concomitant derecruitment in ventral regions, magnitude of this being reduced by positive end-expiratory pressure. Prone position redistributed ventilation toward dorsal and ventral regions at positive end-expiratory pressure 0 and positive end-expiratory pressure, respectively. Finally, prone position redistributed perfusion toward ventral regions, to an extent amplified by positive end-expiratory pressure. CONCLUSIONS:: Positive end-expiratory pressure and posture act synergistically by redistributing lung regional perfusion toward ventral regions, but have antagonistic effects on regional ventilation.}, address = {From the Hospices civils de Lyon (J-CR, GB, CG), Service de R\'{e}animation M\'{e}dicale et d'Assistance Respiratoire, H\^{o}pital de la Croix Rousse; Universit\'{e} de Lyon, Universit\'{e} Lyon 1, Lyon, France; CREATIS (CNRS UMR 5515 et INSERM Unit\'{e} 630) (J-CR, MJ, GG, CG), Lyon, France; Laboratoire de physiopathologie respiratoire (FB), EA 2201, Facult\'{e} de m\'{e}decine, Secteur Nord, Marseille, France; Centre d'\'{e}tude et de recherche multimodal et pluridisciplinaire en imagerie du vivant (CERMEP) (NC, DLB, CT, FL, GG), Lyon, France; and Hospices civils de Lyon, Universit\'{e} de Lyon (MJ), Universit\'{e} Lyon 1, Service de M\'{e}decine Nucl\'{e}aire, H\^{o}pital Edouard Herriot, Lyon, France.}, author = {Richard, Jean-Christophe C. and Bregeon, Fabienne and Costes, Nicolas and Bars, Didier L. and Tourvieille, Christian and Lavenne, Franck and Janier, Marc and Bourdin, Ga\"{e}l and Gimenez, G\'{e}rard and Guerin, Claude}, citeulike-article-id = {2967266}, citeulike-linkout-0 = {http://dx.doi.org/10.1097/CCM.0b013e31818094a9}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18596639}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18596639}, day = {1}, doi = {10.1097/CCM.0b013e31818094a9}, issn = {1530-0293}, journal = {Critical care medicine}, keywords = {dv, peep, sdra}, month = {July}, posted-at = {2008-07-06 13:41:01}, priority = {2}, title = {Effects of prone position and positive end-expiratory pressure on lung perfusion and ventilation.}, url = {http://dx.doi.org/10.1097/CCM.0b013e31818094a9}, year = {2008} }

TY - JOUR ID - citeulike:2967266 L3 - citeulike-article-id:2967266 N2 - OBJECTIVES:: Prone positioning is frequently used during acute respiratory distress syndrome. However, mechanisms by which it improves oxygenation are poorly understood, as well as its interaction with positive end-expiratory pressure. This study was conducted to decipher the respective effects of positive end-expiratory pressure and posture during lung injury on regional lung ventilation, perfusion and recruitment assessed by positron emission tomography. DESIGN:: Experimental study. SETTING:: Research laboratory of a university hospital. SUBJECTS:: Six female piglets. INTERVENTIONS:: After oleic acid-induced lung injury, all animals were studied in supine and prone position at both positive end-expiratory pressure 0 and positive end-expiratory pressure 10 cm H2O. MEASUREMENTS AND MAIN RESULTS:: In each experimental condition, regional lung perfusion and ventilation were assessed with positron emission tomograph using intravenous O-labeled water and inhaled nitrogen-13. Nonaerated lung weight was assessed with positron emission tomograph, and alveolar recruitment was defined as the difference of nonaerated lung weight between conditions. Positive end-expiratory pressure was associated with significant alveolar recruitment (130 +/- 85 and 65 +/- 29 g of lung in supine and prone position, respectively [p < 0.05 vs. 0]), whereas recruitment induced by posture was not statistically significant (77 +/- 97 g with positive end-expiratory pressure 0 and 13 +/- 19 g with positive end-expiratory pressure 10 [p > 0.05 vs. 0]). Regardless the posture, positive end-expiratory pressure redistributed both perfusion and ventilation toward dependent regions. Recruitment by positive end-expiratory pressure was restricted to dorsal regions in supine position, but extended diffusely along the ventral-to-dorsal dimension in prone position. Prone position was associated with recruitment in dorsal regions with concomitant derecruitment in ventral regions, magnitude of this being reduced by positive end-expiratory pressure. Prone position redistributed ventilation toward dorsal and ventral regions at positive end-expiratory pressure 0 and positive end-expiratory pressure, respectively. Finally, prone position redistributed perfusion toward ventral regions, to an extent amplified by positive end-expiratory pressure. CONCLUSIONS:: Positive end-expiratory pressure and posture act synergistically by redistributing lung regional perfusion toward ventral regions, but have antagonistic effects on regional ventilation. JF - Critical care medicine SN - 1530-0293 AD - From the Hospices civils de Lyon (J-CR, GB, CG), Service de Réanimation Médicale et d'Assistance Respiratoire, Hôpital de la Croix Rousse; Université de Lyon, Université Lyon 1, Lyon, France; CREATIS (CNRS UMR 5515 et INSERM Unité 630) (J-CR, MJ, GG, CG), Lyon, France; Laboratoire de physiopathologie respiratoire (FB), EA 2201, Faculté de médecine, Secteur Nord, Marseille, France; Centre d'étude et de recherche multimodal et pluridisciplinaire en imagerie du vivant (CERMEP) (NC, DLB, CT, FL, GG), Lyon, France; and Hospices civils de Lyon, Université de Lyon (MJ), Université Lyon 1, Service de Médecine Nucléaire, Hôpital Edouard Herriot, Lyon, France. TI - Effects of prone position and positive end-expiratory pressure on lung perfusion and ventilation. KW - dv KW - peep KW - sdra AU - Richard, Jean-Christophe AU - Bregeon, Fabienne AU - Costes, Nicolas AU - Bars, Didier AU - Tourvieille, Christian AU - Lavenne, Franck AU - Janier, Marc AU - Bourdin, Gaël AU - Gimenez, Gérard AU - Guerin, Claude PY - 2008/07/01/ UR - http://dx.doi.org/10.1097/CCM.0b013e31818094a9 ER -