Figure 4.
End-expiratory and end-inspiratory Pl over time by treatment assignment. (A) Patients with an APACHE-II score less than median value. (B) Patients with an APACHE-II score greater than median value. Note the much narrower range of end-expiratory Pl values on each of the first 4 days on protocol with the Pes-guided PEEP strategy, indicative of more precise PEEP titration to Pl. Day 0 denotes baseline preintervention values. Once oxygenation improved and remained stable for 24 hours on minimum ventilator requirements, PEEP was weaned empirically without regard for Pl in either arm, partially contributing to the lower values observed on later study days. *Statistically significant difference between treatment groups in the absolute value of end-expiratory Pl (distance from 0 cm H2O) on that study day. #Statistically significant difference between treatment groups in PL at end-inspiration on that study day. APACHE-II = Acute Physiology and Chronic Health Evaluation II; PEEP = positive end-expiratory pressure; Pes = esophageal pressure; Pl = transpulmonary pressure.