Which of the following ventilator modes allow patients to perform part of the work of breathing? 1. Volume-support ventilation 2. Mandatory minute ventilation 3. Continuous mandatory ventilation 4. Proportional assist ventilation

a. 1 and 3 c. 1, 2, and 3
b. 2 and 4 d. 1, 2, and 4

ANS: D
Volume-support ventilation on the Maquet Servo 300 is purely assist mode and is basically a form of pressure-support ventilation except that the volume delivery is targeted over several breaths. Mandatory minute ventilation is a closed-loop form of volume-targeted or pres-sure-targeted ventilation used in patients who can perform part of the work of breathing and are progressing toward weaning from mechanical ventilation. Proportional assist ventilation is a method of assisting spontaneous ventilation in which the practitioner adjusts the amount of the work of breathing assumed by the ventilator.