II. Study Objectives Specific Aim 1: To demonstrate the efficacy of the a maximal recruitment strategy to increase lung volumes and improve oxygenation in children with acute lung injury, utilizing multiple breath nitrogen washout (MBNW) and electrical impedance tomography (EIT) as measures of lung volume. (Hypothesis: Lung volumes and oxygenation will increase following the maximal recruitment protocol as compared to those during 'baseline ventilation' or the 'open lung approach.') Specific Aim 2: To compare lung volumes as measured by MBNW and EIT at varying end-expiratory lung volumes. (Hypothesis: Lung volumes as measured by MBNW will correlate with those obtained by EIT.)