Endotracheal temperature and humidity in laryngectomized patients in a warm and dry environment and the effect of a heat and moisture exchanger

Background. This study was designed to assess endotracheal climate in laryngectomized patients in a warm and dry environment and the effects of a heat and moisture exchanger (HME). Methods. Endotracheal temperature and humidity were measured in 11 laryngectomized patients with a regularly used HME (Provox Normal HME; R-HME), an HME with antimicrobial filter (Provox Micron HME; F-HME), and without HME (open stoma). Measurements were performed at 32 degrees C, 34 degrees C, and 38 degrees C ( <25% relative humidity). Results. Both R-HME and F-HME increased end-inspiratory humidity (AH(insp)) equally (range, 3.4 to 5.6 mgH(2)O/L). The R-HME has a cooling effect on end-inspiratory temperature (T(insp)), which is similar for all tested environmental conditions (-3.8 degrees C); F-HME decreases T(insp) less (range, -1.3 to -0.6 degrees C). Conclusions. In a warm and dry environment, both R- and F-HME significantly cool and humidify inspired air. Therefore, consistent use of an HME under these climate conditions is also probably clinically beneficial. (C) 2010 Wiley Periodicals, Inc. Head Neck 33: 1285-1293, 2011