Figure 2.

Static pressure–volume curve of a rat with aspiration-induced acute lung injury. The shaded areas indicate lung volumes where ventilator-associated lung injury is likely to be most severe based on data from experimental studies. Some clinical studies of protective ventilation in acute respiratory distress syndrome patients have used the lower inflection point of the inspiratory limb as a guide to set the positive end expiratory pressure (PEEP). The events associated with this inflection at the alveolar level are uncertain, however, and a clear inflection is not always apparent. The recent National Insitutes of Health-sponsored Acute Respiratory Distress Syndrome Network study that demonstrated a reduction in mortality did not use a pressure–volume curve to set the PEEP [4].