[Pharmacologic treatment of hypoxemia in adult respiratory distress syndrome]

New drugs that improve arterial oxygenation (nitric oxide, almitrine, inhaled prostacyclin and cyclooxygenase inhibitors) are useful in the treatment of severe hypoxemia unresponsive to conventional treatment that is mainly seen in patients with acute respiratory distress syndrome (ARDS). By acting selectively on pulmonary blood flow and redistributing it, these drugs achieve effects unattainable until now. Thus, they decrease perfusion in non-ventilated zones (V/Q = O) responsible for shunt, or increase perfusion in well ventilated zones, guaranteeing adequate oxygenation. To apply these drugs the physician must understand their mechanism of action, guidelines for dosing, constraints on their use and side effects.