Types of Artificial Humidification for Patients with Tracheostomies

The upper airway, particularly the nose and nasopharynx, is critical in humidifying inspired air. Proper humidification ensures that inspired gases are adequately saturated with water vapor and warmed to body temperature. This process is essential for maintaining intact mucociliary function and for hydrating mucus to manage viscosity and mucus transport ¹. When mucociliary transport is optimal, it effectively clears contaminants and excess secretions from the respiratory tract. In patients with tracheostomy, the upper airway is bypassed. Consequently, the air is no longer conditioned before reaching the trachea which may lead to negative effects on pulmonary health. In this patient population, the addition of artificial humidification is essential.

Two common types of artificial humidification for patients with tracheostomy include Conventional External Humidification Systems (CEHS) and Heat and Moisture Exchangers (HME).

• CEHS act by allowing air to pass through a reservoir of water which is typically heated before being delivered to the patient. Heated humidification has been shown to improve mucociliary transport, leading to improved secretion management and less suctioning needs when compared to cold air nebulization.²
• An HME is a device that attaches directly to the tracheostomy tube, retains moisture and heat from the expired air, and returns it to the patient’s respiratory tract during inspiration. It consists of a housing that provides structural support and a core where the heat and moisture exchange occur. The core is typically made of materials with high thermal capacity and large surface area to improve the humidification benefit from the HME. Materials such as foam or paper that are saturated with a hygroscopic compound, such as calcium chloride, have increased ability to absorb and release moisture and improve the performance of the HME.^3,4

See HME Evidence and Benefits to learn more about the many benefits of HMES by clicking the button below.

References:

¹Mercke U, Toremalm NG. Air humidity and mucociliary activity. Ann Otol Rhinol Laryngol. 1976 Jan-Feb;85 (1 Pt 1):32-7.
²Birk R, Händel A, Wenzel A, Kramer B, Aderhold C, Hörmann K, Stuck BA, Sommer JU. Heated air humidification versus cold air nebulization in newly tracheostomized patients. Head Neck. 2017 Dec;39(12):2481-2487.
³Wilkes AR. Heat and moisture exchangers. Structure and function. Respir Care Clin N Am. 1998;4(2):261-79.
⁴van den Boer C, Vas Nunes JH, Muller SH, van dN, V, van den Brekel MW, Hilgers FJ. Water Uptake Performance of Hygroscopic Heat and Moisture Exchangers after 24-Hour