PRONE VENTILATION - 05/09/11
Résumé |
In 1922, Beams and Christie12 first reported that vital capacity was lower when measured in the supine than in the upright posture. In 1933, Hurtado and Frey28 extended this observation to include functional residual capacity (FRC), and McMichael and McGibbon attributed the difference to the weight of the abdomen in 1939.39 In 1955, Blair and Hickham5 first noted that body position alters gas mixing. The fact that the prone position might counter these adverse effects dates to 1961, when Moreno and Lyons noted that the FRC measured prone was higher than that measured supine.42
Mellins referred to the aforementioned observations in a presentation at a conference on the scientific basis of respiratory therapy in 1974,40 and concluded that the transpulmonary pressure opposing lung collapse could vary markedly depending on body position. In discussing this presentation, Bryan10 reviewed the results of a study he and Froese had recently completed18 that suggested the reduction in FRC that occurred when lying supine was primarily localized to dorsal lung regions, and was the first to suggest that the only “feasible” method of expanding these regions would be to ventilate patients in the prone position.
The first documentation that the prone position actually improved oxygenation was provided in 1976 and 1977,15, 48 in patients with the acute respiratory distress syndrome (ARDS), but these observations went largely unrecognized until 1987, when the effects of prone positioning were first studied mechanistically,1 and the clinical observations were repeated by Langer and colleagues in 1988.34 Additional laboratory studies were published in the early 1990s24, 33, 44, 45, 58 and were followed by numerous confirmatory clinical reports from around the world, which continue to date.*
This article reviews the clinical information regarding the effects of prone ventilation on gas exchange in patients with ARDS, discusses the mechanisms by which this improvement occurs, and considers how prone ventilation might also reduce ventilator-induced lung injury.
Le texte complet de cet article est disponible en PDF.Plan
| Address reprint requests to Richard K. Albert, MD, Denver Health Medical Center, 777 Bannock, MC 4000, Denver, CO 80204–4507, e-mail: RAlbert@dhha.org |
Vol 21 - N° 3
P. 511-517 - septembre 2000 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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