Mechanical support of acute lung injury: Options for strategic ventilation

The acute respiratory distress syndrome is a significant cause of morbidity in critically ill children. While therapeutic interventions remain supportive, the management of evolving acute lung injury is often a controversial issue in the pediatric ICU. There has been significant progress in our understanding of the pathophysiology of acute lung injury and in our understanding of how lung injury is often amplified in the course of mechanical support. This understanding has led to a strategic shift in ventilation style principally geared to optimally recruiting and then maintaining end-expiratory lung volume, preventing the traumatic cycle of derecruitment-recruitment, and finally, limiting alveolar stretching during tidal inflation. We will review the evidence supporting this strategy from the data generated in both the animal laboratory and recently in adult clinical trials. We will discuss how tidal ventilation dynamics and conventional mode selection, patient positioning, adjuncts to conventional ventilation, high-frequency oscillatory ventilation, and permissive hypercapnia fit within this strategy.