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Effects of prone positioning on lung protection in patients with acute respiratory distress syndrome.

Authors :
Cornejo RA
Díaz JC
Tobar EA
Bruhn AR
Ramos CA
González RA
Repetto CA
Romero CM
Gálvez LR
Llanos O
Arellano DH
Neira WR
Díaz GA
Zamorano AJ
Pereira GL
Source :
American journal of respiratory and critical care medicine [Am J Respir Crit Care Med] 2013 Aug 15; Vol. 188 (4), pp. 440-8.
Publication Year :
2013

Abstract

Rationale: Positive end-expiratory pressure (PEEP) and prone positioning may induce lung recruitment and affect alveolar dynamics in acute respiratory distress syndrome (ARDS). Whether there is interdependence between the effects of PEEP and prone positioning on these variables is unknown.<br />Objectives: To determine the effects of high PEEP and prone positioning on lung recruitment, cyclic recruitment/derecruitment, and tidal hyperinflation and how these effects are influenced by lung recruitability.<br />Methods: Mechanically ventilated patients (Vt 6 ml/kg ideal body weight) underwent whole-lung computed tomography (CT) during breath-holding sessions at airway pressures of 5, 15, and 45 cm H2O and Cine-CTs on a fixed thoracic transverse slice at PEEP 5 and 15 cm H2O. CT images were repeated in supine and prone positioning. A recruitment maneuver at 45 cm H2O was performed before each PEEP change. Lung recruitability was defined as the difference in percentage of nonaerated tissue between 5 and 45 cm H2O. Cyclic recruitment/de-recruitment and tidal hyperinflation were determined as tidal changes in percentage of nonaerated and hyperinflated tissue, respectively.<br />Measurements and Main Results: Twenty-four patients with ARDS were included. Increasing PEEP from 5 to 15 cm H2O decreased nonaerated tissue (501 ± 201 to 322 ± 132 grams; P < 0.001) and increased tidal-hyperinflation (0.41 ± 0.26 to 0.57 ± 0.30%; P = 0.004) in supine. Prone positioning further decreased nonaerated tissue (322 ± 132 to 290 ± 141 grams; P = 0.028) and reduced tidal hyperinflation observed at PEEP 15 in supine patients (0.57 ± 0.30 to 0.41 ± 0.22%). Cyclic recruitment/de-recruitment only decreased when high PEEP and prone positioning were applied together (4.1 ± 1.9 to 2.9 ± 0.9%; P = 0.003), particularly in patients with high lung recruitability.<br />Conclusions: Prone positioning enhances lung recruitment and decreases alveolar instability and hyperinflation observed at high PEEP in patients with ARDS.

Details

Language :
English
ISSN :
1535-4970
Volume :
188
Issue :
4
Database :
MEDLINE
Journal :
American journal of respiratory and critical care medicine
Publication Type :
Academic Journal
Accession number :
23348974
Full Text :
https://doi.org/10.1164/rccm.201207-1279OC