Figure 3

Comparison of alveolar derecruitment assessed by the computed tomography and pressure–volume curve methods. In the left panel, the linear correlation existing between the two methods is represented. In the right panel, the agreement between the two methods is represented with the Bland and Altman analysis. Open circles indicate 12 patients in whom alveolar derecruitment was measured by both methods immediately after the disconnecting maneuver; closed circles identify seven patients in whom alveolar derecruitment was measured by both methods 15 minutes after PEEP withdrawal. The bias was expressed as the mean difference between the derecruited volume measured by the P–V curve method and the average value of the two methods. The limits of agreement were defined as 2 SD.