Journal article
Mechanism by which the prone position improves oxygenation in acute lung injury
American journal of respiratory and critical care medicine, Vol.150(1), pp.184-193
07/1994
DOI: 10.1164/ajrccm.150.1.8025748
PMID: 8025748
Abstract
The mechanism by which oxygenation improves when patients with ARDS are turned from supine to prone position is not known. From results of our previous studies we reasoned that (1) when supine, in the setting of lung injury, transpulmonary pressure will be less than airway opening pressure and (2) atelectasis will develop preferentially in dorsal lung areas, and (3) both ventilation and ventilation/perfusion ratios would improve in these regions on turning prone. To study this directly, we measured regional ventilation and perfusion using 81mKr and 99mTc-MAA, respectively, and single photon emission computed tomography, both prone and supine, in four control animals and four given oleic acid. After oleic acid, the prone position improved (1) oxygenation (mean +/- SD PaO2 = 140 +/- 112 versus 453 +/- 54 mm Hg), (2) median ventilation/perfusion ratios (0.77 versus 0.95), (3) ventilation/perfusion heterogeneity (coefficient of variation 86 +/- 15 versus 61 +/- 6), and (4) the gravitational ventilation/perfusion gradient (dependent to non-dependent slopes of 0.22 versus -0.02, all p < 0.05). The prone position generates a transpulmonary pressure sufficient to exceed airway opening pressure in dorsal lung regions, i.e., in regions where atelectasis, shunt, and ventilation/perfusion heterogeneity are most severe, without adversely affecting ventral lung regions.
Details
- Title: Subtitle
- Mechanism by which the prone position improves oxygenation in acute lung injury
- Creators
- W J Lamm - Department of Medicine, University of Washington, SeattleM M GrahamR K Albert
- Resource Type
- Journal article
- Publication Details
- American journal of respiratory and critical care medicine, Vol.150(1), pp.184-193
- Publisher
- United States
- DOI
- 10.1164/ajrccm.150.1.8025748
- PMID
- 8025748
- ISSN
- 1073-449X
- eISSN
- 1535-4970
- Language
- English
- Date published
- 07/1994
- Academic Unit
- Radiology; Radiation Oncology
- Record Identifier
- 9984047991802771
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