Which of the following ventilator modes is represented by the pressure-time scalar in the figure?

a. Volume-controlled intermittent mandatory ventilation with positive end-expiratory pressure
b. Pressure-controlled intermittent mandato-ry ventilation with positive end-expiratory pressure
c. Pressure-augmented, volume-guaranteed breaths
d. Proportional assist ventilation

ANS: B
The pressure-time waveform is raised from the zero line; this means that there is positive end-expiratory pressure. The flat pressure wave is indicative of pressure-limited breaths. The higher level represents the ventilator pressure-limited breath, and the lower level waveform rep-resents the pressure-supported breaths.