BACKGROUND: Breathing through a tracheostoma results in insufficient warming and humidification of the inspired air. This loss of air conditioning, especially humidification, can be partially restored with the application of a heat and moisture exchanger (HME) over the tracheostoma. For medical professionals, it is not easy to judge differences in water exchange performance of various HMEs owing to the lack of universal outcome measures. This study has three aims: assessment of the water exchange performance of commercially available HMEs for laryngectomized patients, validation of these results with absolute humidity outcomes, and assessment of the role of hygroscopic salt present in some of the tested HMEs. METHODS: Measurements of weight and absolute humidity at end inspiration and end expiration at different breathing volumes of a healthy volunteer were performed using a microbalance and humidity sensor. Twenty-three HMEs from 6 different manufacturers were tested. Associations were determined between core weight, weight change, breathing volume, and absolute humidity, using both linear and nonlinear mixed effects models. RESULTS: Water exchange of the 23 HMEs at a breathing volume of 0.5 L varies between 0.5 and 3.6 mg. Both water exchange and wet core weight correlate strongly with the end-inspiratory absolute humidity values (r 2 ؍ 0.89/0.87). Hygroscopic salt increases core weight. CONCLUSIONS: The 23 tested HMEs for laryngectomized patients show wide variation in water exchange performance. Water exchange correlates well with the end-inspiratory absolute humidity outcome, which validates the ex vivo weight change method. Wet core weight is a predictor of HME performance. Hygroscopic salt increases the weight of the core material. The results of this study can help medical professionals to obtain a more founded opinion about the performance of available HMEs for pulmonary rehabilitation in laryngectomized patients, and allow them to make an informed decision about which HME type to use.
BACKGROUND: Breathing through a tracheostomy results in insufficient warming and humidification of inspired air. This loss of air-conditioning can be partially compensated for with the application of a heat and moisture exchanger (HME) over the tracheostomy. In vitro (International Organization for Standardization [ISO] standard 9360 -2:2001) and in vivo measurements of the effects of an HME are complex and technically challenging. The aim of this study was to develop a simple method to measure the ex vivo HME performance comparable with previous in vitro and in vivo results. METHODS: HMEs were weighed at the end of inspiration and at the end of expiration at different breathing volumes. Four HMEs (Atos Medical, Hörby, Sweden) with known in vivo humidity and in vitro water loss values were tested. The associations between weight change, volume, and absolute humidity were determined using both linear and non-linear mixed effects models. RESULTS: The rating between the 4 HMEs by weighing correlated with previous intratracheal measurements (R 2 ؍ 0.98), and the ISO standard (R 2 ؍ 0.77). CONCLUSIONS: Assessment of the weight change between end of inhalation and end of exhalation is a valid and simple method of measuring the water exchange performance of an HME.
Analysis of the clinical value of histopathological examination of material collected during functional endoscopic sinus surgery. Retrospective analysis of collected data of patients undergoing functional endoscopic sinus surgery over a 7-year period. Data were collected from a pathology database of the Sint Lucas Andreas Hospital, Amsterdam, The Netherlands. All material collected from 1,944 functional endoscopic sinus surgery cases in 1,695 patients (some patients underwent revision surgery) operated between 2000 and 2007 was examined histologically. Patients with a histological outcome different from chronic inflammation or polyposis nasi, were checked on indication of surgery, type of surgery and preoperative clinical suspicion for (pre)malignancy. The impact of the histological diagnosis on the clinical course was evaluated. Thirty-seven unusual diagnoses were reported: 18 cases of inverted papilloma, one squamous cell carcinoma, two malignant lymphomas, one leiomyosarcoma, eight squamous cell papillomas, one Churg Strauss syndrome, one Schneiderian papilloma, two cases of Wegener’s granulomatosis and three cases of sarcoidosis. All other specimens were identified as chronic inflammation and/or nasal polyposis. Only two clinically significant, unexpected diagnoses, both inverted papilloma, have resulted from the histological investigation. We conclude that the close correlation between histopathology outcome and examination on clinical grounds or gross inspection indicates that routine histopathological examination of functional endoscopic sinus surgery material has little clinical value and it is questionable if this should be performed. In patients in whom there is a high degree of suspicion for (pre)malignancy, histopathological examination of functional endoscopic sinsus surgery material remains indicated.
Laryngectomized patients, lacking conditioning of the breathing air in the upper respiratory tract, have reported considerable pulmonary complaints. It is assumed that these patients also run a higher risk of developing severe respiratory infections. Unfortunately, there is little scientific information available about the occurrence of respiratory infections and related health costs in these patients with and without the use of an HME. Therefore, the occurrence of respiratory infections in laryngectomized patients was investigated in the Netherlands Cancer Institute and by means of a survey among head and neck oncology surgeons throughout Europe. The number of tracheobronchitis and/or pneumonia events was retrospectively scored between 1973 and 2013 in medical records of 89 laryngectomized patients treated in our institute. To assess expert experiences and opinions regarding these pulmonary problems, a study-specific survey was developed. The survey was sent by email to head and neck surgeons from ten different countries. In the medical record study, an average of 0.129 respiratory infections per patient/year was found in non-HME users and 0.092 in HME users. In the survey (response rate HN surgeons 20 %; countries 90 %) 0.285 episodes per patient/year in non-HME users was statistically higher than the 0.066 episodes per patient/year in HME users. The average mortality in the HME user group per entire career of each physician was estimated at 0.0045, and for the non-HME user group this was 0.0152. There is a tendency that the number of tracheobronchitis and pneumonia episodes in non-HME users is higher than in HME users.
The beneficial physical and psychosocial effects of heat and moisture exchangers (HMEs) for pulmonary rehabilitation of laryngectomy patients are well evidenced. However, cost-effectiveness in terms of costs per additional quality-adjusted life years (QALYs) has not yet been investigated. Therefore, a model-based cost-effectiveness analysis of using HMEs versus usual care (UC) (including stoma covers, suction system and/or external humidifier) for patients after laryngectomy was performed. Primary outcomes were costs, QALYs and incremental cost-effectiveness ratio (ICER). Secondary outcomes were pulmonary infections, and sleeping problems. The analysis was performed from a health care perspective of Poland, using a time horizon of 10 years and cycle length of 1 year. Transition probabilities were derived from various sources, amongst others a Polish randomized clinical trial. Quality of life data was derived from an Italian study on similar patients. Data on frequencies and mortality-related tracheobronchitis and/or pneumonia were derived from a Europe-wide survey amongst head and neck cancer experts. Substantial differences in quality-adjusted survival between the use of HMEs (3.63 QALYs) versus UC (2.95 QALYs) were observed. Total health care costs/patient were 39,553 PLN (9465 Euro) for the HME strategy and 4889 PLN (1168 Euro) for the UC strategy. HME use resulted in fewer pulmonary infections, and less sleeping problems. We could conclude that given the Polish threshold of 99,000 PLN/QALY, using HMEs is cost-effective compared to UC, resulting in 51,326 PLN/QALY (12,264 Euro/QALY) gained for patients after total laryngectomy. For the hospital period alone (2 weeks), HMEs were cost-saving: less costly and more effective.
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