Which of the following is NOT an essential capability of an adult ICU ventilator?

• A. Flow rates up to 200 L/min
• B. Ability to deliver tidal volumes
• C. Adjustable FiO2
• D. Provides PEEP

Answer: (A)

The key idea here is what an adult ICU ventilator must reliably do to support ventilation and oxygenation. An essential ventilator function is delivering a controlled tidal volume to ensure adequate ventilation and CO2 removal, adjusting the inspired oxygen fraction (FiO2) to meet the patient’s oxygen needs, and applying positive end-expiratory pressure (PEEP) to keep airways open and improve oxygenation. These three capabilities are fundamental to invasive mechanical ventilation.

Flow rates up to 200 L/min are not required for this basic purpose. Most invasive ventilators achieve the needed tidal delivery and oxygenation with much lower peak inspiratory flows, and the core requirements are controlling volume (or pressure), FiO2, and PEEP. High flow capability is more of a supplementary or specialized feature rather than a core necessity for standard adult ICU ventilation.