Goal-directed therapy for severely hypoxic patients with acute respiratory distress syndrome: permissive hypoxemia.

Permissive hypoxemia is a lung-protective strategy that aims to provide a patient with severe acute respiratory distress syndrome (ARDS) a level of oxygen delivery that is adequate to avoid tissue hypoxia while minimizing the detrimental effects of the often toxic ventilatory support required to maintain normal arterial oxygenation. However, in many patients with severe ARDS it can be difficult to achieve a balance between maintaining adequate tissue oxygenation and avoiding ventilator-induced lung injury (VILI). A potential strategy for the management of such patients involves goal-oriented manipulation of cardiac output and, if necessary, hemoglobin concentration, to compensate for hypoxemia and maintain a normal (but not supranormal) value of oxygen delivery. Although it has not yet been studied, this approach is theorized to improve clinical outcomes of critically ill patients with severe ARDS. We stress that the goal of this article is not to convince the reader that this approach is necessarily correct, as data are clearly lacking, but rather to provide a basis for continued thought, discussion, and potential research.