Increased elastic pressure (eg, > 10 cm H2O) suggests decreased lung compliance due to Edema, fibrosis, or lobar atelectasis Large pleural effusions, pneumothorax, or fibrothorax Extrapulmonary restriction as may result from circumferential burns or another chest wall deformity, ascites, pregnancy, or massive obesity A tidal volume too large for the amount of lung being ventilated (eg, a normal tidal volume being delivered to a single lung because the endotracheal tube is malpositioned) Intrinsic PEEP (auto PEEP) can be measured in the passive patient through an end-expiratory hold maneuver.