Figure 2

Tracings obtained from ventilator while operating in the volume-controlled mode. Flow, pressure, and volume in time are presented from top to bottom. The dashed circle in the upper panel shows the truncated expiratory flow tracing, indicating intrinsic positive end-expiratory pressure (PEEP). Indeed, when expiration is interrupted (red solid arrow) after the next inspiration, airway pressure rises (middle panel), reflecting total PEEP (applied PEEP and intrinsic PEEP). To measure respiratory resistance, inspiratory hold is applied (red dotted arrow), resulting in rapid decay in airway pressure from peak to P1 and a subsequent slow decay to plateau pressure (P,plat).