Acute lung injury and acute respiratory distress syndrome are syndromes of severe respiratory failure. Children with acute lung injury or acute respiratory distress syndrome have high mortality and significant morbidity. Partial liquid ventilation is proposed as a less injurious form of respiratory support for these children. Uncontrolled studies in adults have shown improvements in gas exchange and lung compliance with partial liquid ventilation. A single uncontrolled study in six children with acute respiratory syndrome showed some improvement in gas exchange during three hours of partial liquid ventilation.