TY - JOUR T1 - In Vitro Evaluation of Heat and Moisture Exchangers Designed for Spontaneously Breathing Tracheostomized Patients JF - Respiratory Care SP - 1878 LP - 1885 DO - 10.4187/respcare.02405 VL - 58 IS - 11 AU - Claudia Brusasco AU - Francesco Corradi AU - Maria Vargas AU - Margherita Bona AU - Federica Bruno AU - Maria Marsili AU - Francesca Simonassi AU - Gregorio Santori AU - Paolo Severgnini AU - Robert M Kacmarek AU - Paolo Pelosi Y1 - 2013/11/01 UR - http://rc.rcjournal.com/content/58/11/1878.abstract N2 - BACKGROUND: Heat and moisture exchangers (HMEs) are commonly used in chronically tracheostomized spontaneously breathing patients, to condition inhaled air, maintain lower airway function, and minimize the viscosity of secretions. Supplemental oxygen (O2) can be added to most HMEs designed for spontaneously breathing tracheostomized patients. We tested the efficiency of 7 HMEs designed for spontaneously breathing tracheostomized patients, in a normothermic model, at different minute ventilations (V̇E) and supplemental O2 flows. METHODS: HME efficiency was evaluated using an in vitro lung model at 2 V̇E (5 and 15 L/min) and 4 supplemental O2 flows (0, 3, 6, and 12 L/min). Wet and dry temperatures of the inspiratory flow were measured, and absolute humidity was calculated. In addition, HME efficiency at 0, 12, and 24 h use was evaluated, as well as resistance to flow at 0 and 24 h. RESULTS: The progressive increase in O2 flow from 0 to 12 L/min was associated with a reduction in temperature and absolute humidity. Under the same conditions, this effect was greater at lower V̇E. The HME with the best performance provided an absolute humidity of 26 mg H2O/L and a temperature of 27.8°C. No significant changes in efficiency or resistance were detected during the 24 h evaluation. CONCLUSIONS: The efficiency of HMEs in terms of temperature and absolute humidity is significantly affected by O2 supplementation and V̇E. ER -