Physiologic variables in a representative nonresponder and in a responder acute respiratory distress syndrome (ARDS) patient before, during, and after recruitment maneuvers (RMs). In patients with a stiff chest wall (nonresponders) the degree of airway pressure transmitted to the pleural space was greater. Subsequently, during the RM, the transpulmonary pressure and the change in lung volume were lower. The reduction in blood pressure was higher in nonresponders than in patients with normal chest wall (responders). From top to bottom: flow, airway opening pressure (Pao), and changes in lung volume (ΔV), esophageal pressure (ΔPes), transpulmonary pressure (PL), arterial blood pressure (ABP), and right atrial pressure (RAP) with worsening hemodynamics. Reproduced and modified with permission from Grasso and coworkers .