This study assesses intra-and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P \ 0.0001). With HME, end-inspiratory (minimum) humidity values increased 5.8 mg H 2 O/L (P \ 0.0001) and minimum temperature values decreased 1.6°C (P \ 0.0001). For the temperature and humidity minimums, the inter-patient variability was much smaller than the short-and long-term intra-patient variability. For exhalation breath length and full breath length, the opposite was the case. Conclusions: (1) Because inter-patient variability is smaller than intrapatient variability, investigating endotracheal climate in a limited number of laryngectomized subjects is justified, provided repeated measurements per patient are accomplished; (2) main contributor to intra-patient variability is the positioning of the catheter tip in the trachea; (3) an HME leads to a shortened IBL which enhances the HME effect.

Both HMEs significantly improve tracheal climate. The R-HME has better moistening properties and a small but significant positive effect on tidal volume. Therefore, if the higher resistance is tolerated, the R-HME is the preferred pulmonary rehabilitation device. The L-HME is indicated if lower breathing resistance is required.

Both R-HME and F-HME increase endotracheal minimum humidity values (5.8 and 4.7 mgH(2)O/L, respectively; p < 0.0001). Compared with open stoma breathing, in contrast to the R-HME, the F-HME increases both end-inspiratory and end-expiratory temperature values (1.1 degrees C, and 0.6 degrees C, respectively). After the 3-week clinical feasibility trial, one patient dropped out; 11 patients (11/16 = 69%) disliked the larger design of the F-HME and all patients reported less optimal airtight occlusion. Five patients (5/16 = 31%) reported remarkably decreased sputum production.

Peripheral vestibular loss was found in seven patients (7/23 = 30.4%). Central vestibular loss was found in one patient. Analysis of the 19 completed questionnaires showed that 12 patients (12/19 = 63.2%) did not experience dizziness and 3 patients (3/19 = 15/8%) experienced specific vestibular symptoms. The results of the questionnaire could not predict the results of ENG with caloric irrigation. Physical examination showed no abnormalities in any patients. No age- or dose-related predictive factors were found.