Purpose of review: To describe the physiologic and diagnostic utility of static pressure-volume curves of the respiratory system at the bedside in patients with acute lung injury or acute respiratory distress syndrome.
Recent findings: The pressure-volume curve of the respiratory system is a useful tool for the measurement of respiratory system mechanics in patients with acute lung injury or acute respiratory distress syndrome. The pressure-volume curve has a sigmoid shape, with lower and upper points on the inspiratory limb and a point of maximum curvature on the expiratory limb. Visual and mathematical pressure-volume curve analysis may be useful for understanding individual lung mechanics and for selecting ventilator settings. Among the different techniques for acquiring pressure-volume curves at the bedside, the constant slow flow method is the simplest to perform, the most clinically reliable and has the fewest limitations.
Summary: Measurement of pressure-volume curves at the bedside in critically ill patients with acute lung injury or acute respiratory distress syndrome should be considered a useful respiratory monitoring tool to assess physiologic lung status and to adjust ventilator settings, when appropriate, to minimize superimposed lung injury associated with mechanical ventilators.