Figure 3.

A study patient with obesity and volume overload. Waveforms were collected at zero PEEP initially where significant intrinsic PEEP is noted to 8 cmH₂O. Esophageal pressures are elevated to 12 cmH₂O resulting in a negative transpulmonary pressure that encourages collapse. PEEP was adjusted to 12 cmH₂O until the total PEEP matched the measured esophageal pressures resulting in transpulmonary pressures greater than zero. PEEP, positive end expiratory pressure.