In a ventilator circuit, which device is specifically designed to provide heated and humidified gas by moisture exchange?

• A. Wick humidifier
• B. Cascade humidifier
• C. Large reservoir nebulizer
• D. Heat moisture exchanger

Answer: (A)

Delivering heated, humidified gas is essential to protect the airway during ventilation. The wick humidifier accomplishes this by passing inspired gas through a porous, water-soaked wick that is kept at a warm temperature. The gas picks up moisture as it travels through the wick, and the nearby heater maintains warmth, delivering gas that is near body temperature and saturated with water vapor. This combination provides true heated humidification via moisture transfer, which is why it’s the best answer in this scenario.

A heat moisture exchanger, by contrast, is a passive device that relies on moisture exchange with exhaled gas to humidify inspired gas; it does not actively heat the gas. Nebulizers are designed for delivering medications and aren’t intended to provide continuous humidification. The cascade humidifier is another design that humidifies gas, but it doesn’t specifically rely on the same moisture-exchange mechanism plus heating as the wick-based system.