In which of the following modes of ventilatory support would the patient's work of breathing be least?

a. Continuous positive airway pressure (CPAP)
b. Pressure-supported ventilation (PSV)
c. Intermittent mandatory ventilation (IMV)
d. Continuous mandatory ventilation (CMV)

ANS: D
As the mode is changed from CPAP to PSV to synchronized intermittent mandatory ventilation to time-triggered CMV, the ventilator assumes more of the work.