Fig. 4. Modified pressure–time product (PTPmod) during each ventilatory condition: at pressure control levels of 16, 12, 8, 4, and 0 cm H2O and after extubation. Data are presented as median and 25–75% percentiles. *P < 0.05 versus pressure control of 16 cm H2O; †P < 0.05 versus 12 cm H2O; ‡P < 0.05 versus 8 cm H2O; and §P < 0.05 versus 4 cm H2O.