A heat moisture exchanger is indicated for humidification in which of the following situations?

• A. Mechanical ventilation in a long-term care facility
• B. Transport to a tertiary care center
• C. Patient with tenacious secretions
• D. Delivery of aerosolized bronchodilators

Answer: (B)

Heat moisture exchangers provide passive humidification by capturing heat and moisture from exhaled gas and returning some of it to the next breath. They’re compact, inexpensive, and don’t require a water source or power, making them especially useful when a full heated humidifier isn’t available. That’s why they’re indicated for humidification during transport to another facility—the circuit can stay humidified without bulky equipment in transit.

In other situations, such as long-term care facility ventilation, active humidification is typically used to maintain adequate humidity over extended periods. For a patient with very tenacious secretions, relying solely on an HME may not provide sufficient humidity and could add dead space and resistance, so more aggressive humidification or airway clearance strategies are preferred. Aerosolized bronchodilators are delivered with nebulizers or dedicated delivery methods, not primarily via an HME.