Study of humidification potential of a heat and moisture exchanger in tracheotomized dogs

Though a heat and moisture exchanger (HME) has been used in clinical practice following a tracheotomy on a limited basis, no work has been done to document the humidification potential of an HME in this situation. Eighteen dogs underwent tracheotomy and were killed at either 1 day (nine dogs) or 10 days (nine dogs) postoperatively. Following the tracheotomy, the animals were divided into three groups according to the type of humidification received: ambient conditions, warm mist, or HME. The tracheal mucosa was studied for histologic changes in the cilia, the epithelium, submucosal reaction, and mucus production at the level of the carina. The results were significant (p = .02) for the interaction of the experimental type and method of treatment in their effect on the histologic changes noted at the carina. The study supports the use of an HME as an alternative for long-term humidification in a patient with a tracheotomy.