Which statement correctly describes heat and moisture exchangers (HMEs)?

Which statement correctly describes heat and moisture exchangers (HMEs)?

• A. They are a single device used only with tracheostomy patients.
• B. They remove humidity from inspired air.
• C. They are two types: one for tracheostomy patients and one for ventilated patients.
• D. They are used to deliver heated oxygen.

Answer: (D)

Heat and moisture exchangers are passive devices placed in the breathing circuit to conserve heat and moisture from the patient’s exhaled air and return it to the inspired gas. This keeps the airway humidified and warm without actively heating the gas. They don’t deliver heated oxygen; that function belongs to heated humidification systems. HMEs can be used with artificial airways such as endotracheal tubes or tracheostomies, and they come in different designs, but their primary role is to preserve and transfer humidity, not to supply heated oxygen.

Heat and moisture exchangers are passive devices placed in the breathing circuit to conserve heat and moisture from the patient’s exhaled air and return it to the inspired gas. This keeps the airway humidified and warm without actively heating the gas. They don’t deliver heated oxygen; that function belongs to heated humidification systems. HMEs can be used with artificial airways such as endotracheal tubes or tracheostomies, and they come in different designs, but their primary role is to preserve and transfer humidity, not to supply heated oxygen.