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Background: The beneficial function of heat and moisture exchangers (HMEs) is undisputed, but knowledge of their effects on intra-airway temperature and humidity is scarce. The aim of this study was to evaluate the clinical applicability of a new airway climate explorer (ACE) and to assess the HME's influence on tracheal climate., Methods: Intratracheal temperature and humidity were measured with and without HME in 10 laryngectomized patients., Results: An HME causes the intratracheal mean humidity minima to increase with 3.2 mg H(2)O/L (95% CI: 1.5-4.8 mg H(2)O/L; p <.001), from 21.4 to 24.6 mg H(2)O/L, and the mean temperature minima to decrease with 1.6 degrees C (95% CI: 0.9-2.4 degrees C; p <.001) from 28.5 degrees C to 26.9 degrees C. Relative humidity values suggest that the tested HME keeps inspired air (nearly) fully saturated during the full course of inspiration., Conclusion: Assessment of intratracheal temperature and humidity, and evaluation of HME effectiveness is feasible with the ACE. The tested HME significantly increases the intratracheal humidity, but decreases the intratracheal temperature. Relative humidity calculations suggest that increasing the thermal capacity of this rehabilitation device can further increase the heat and moisture exchange efficiency.

Background: High-resistance heat and moisture exchangers (HMEs) have been reported to increase transcutaneous oxygenation (tcpO(2)) values in laryngectomized individuals and to negatively influence patient compliance. The goal of the present study was to validate earlier published results on short-term transcutaneous oxygenation changes by high-resistance HMEs., Methods: We conducted a randomized crossover study, monitoring the influence of an HME on tcpO(2) over a 2-hour time interval in 20 subjects., Results: No evidence of an immediate HME effect (95% CI: -14.9-13.3 mm Hg, p = .91), or a time-dependent HME effect (95% CI: -.121 - .172 mm Hg/minute, p = .74), on tcpO(2) was found. After fitting the statistical model without time dependency, again no evidence of HME presence was seen (95% CI: -.5 mm Hg - 3.6 mm Hg, p = .15)., Conclusion: In contrast to earlier suggestions, there is no evidence of increased tcpO(2) levels by high-resistance HMEs in laryngectomized individuals. Thus, using such HMEs has no added clinical value in this respect.