What is the role of a heated humidifier in mechanical ventilation?

• A. To warm and humidify the inspired gas to prevent airway and lung injury
• B. To cool the inspired air for better absorption
• C. To filter out bacteria from the inspired gas
• D. To increase the pressure of delivered gases

Answer: (A)

The role of a heated humidifier in mechanical ventilation is primarily to warm and humidify the inspired gas, which is essential in preventing airway and lung injury. When patients are mechanically ventilated, the gas delivered may not have the same temperature and moisture content as natural room air. This dry, cool gas can lead to various complications, including damage to the airway mucosa and the lungs, increased mucus viscosity, and impaired mucociliary function.

By using a heated humidifier, the inspired air is brought to body temperature (approximately 37°C) and is fully saturated with water vapor, mimicking the natural conditions of the respiratory tract. This added moisture helps to maintain appropriate airway humidity levels, preventing dehydration of the airway tissues and assisting in the effective clearance of secretions. This is crucial in critical care settings where patients may have compromised respiratory function.

The other options describe functions that do not align with the primary purpose of a heated humidifier. There isn't a role for cooling inspired air, filtering out bacteria is typically done by other filtration systems or heat and moisture exchangers, and increasing the gas pressure is a function related to ventilator settings rather than humidification.