Customized factory of Heat Moisture Exchanger Filter in China. Heat Moisture Exchanger Filter uses the patient's own humidity and moisture from the exhaled breath to humidify the anesthetic gas during inhalation. Once the patient is intubated, the upper airway is bypassed, which results in a loss of humidification of the inhaled air. Dry air can have detrimental effects on the patient, so to prevent trauma to the patient, a hygroscopic HME can be used instead of the upper airway to act as a humidifier.