Ventilation in the prone position in patients with acute lung injury/acute respiratory distress syndrome.
OBJECTIVE
To contrast the beneficial effects of the prone position on the lungs and the lack of proven clinical benefits on patient outcome.


RESULTS
Recent human investigations in acute respiratory distress syndrome have shown that the prone position was able to abolish tidal expiratory flow limitation, to improve oxygenation in the case of localized infiltrates, to allow for reducing positive end-expiratory pressure level, and to reduce lung stress and strain. Experimental studies have confirmed that distribution of ventilation was more homogeneous in the prone position but showed that positive end-expiratory pressure affected ventilation distribution differently in the prone and in the supine position. Experimental work has also shown that proning reduced strains imposed on the lungs and made them more homogeneously distributed. Finally, one recent large randomized controlled trial of systematic proning in hypoxemic patients showed no reduction in mortality but less ventilator-associated pneumonia incidence in the prone position group.


CONCLUSIONS
The prone position is not systematically used in hypoxemic patients. Patients who could benefit from prone position sessions are those with the most severe acute respiratory distress syndrome and those with dorsal lung infiltrates. Whether this can be translated into improvement in patient outcome has yet to be tested in clinical trials.
Guérin
Claude
C
Medical Intensive Care Unit and Ventilatory Assistance and CREATIS, Research and Applications Center in Image and Signal Processing, Lyon, France. claude.guerin@chu-lyon.fr
D003422:Critical Care; D006801:Humans; D010477:Perfusion; D016684:Prone Position; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D015656:Respiratory Mechanics; D016896:Treatment Outcome