The static pressure–volume curve does not predict the mechanical properties of the respiratory system during mechanical ventilation in acute respiratory distress syndrome (ARDS) and acute lung injury (ALI)

The pathophysiology of ALI and ARDS induces distinct changes in respiratory mechanics. For more than 30 years respiratory mechanics have been assessed by analysis of the static pressure–volume (P–V) curve. Ventilation, however, is a dynamic process and the mechanical properties of the respiratory system can be assessed under dynamic conditions [1]. If the respiratory system shows a specific dynamic behaviour that is not present during static conditions, differing results are to be expected if mechanics are analysed during dynamic conditions. The aim of the present study was to test whether such differences can be observed in ARDS and ALI.