The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

HUMIDIFICATION DURING HIGH FREQUENCY OSCILLATION VENTILATION FOR ADULTS

Yusuke Chikata1,2, Hideaki Imanaka1, Masahiko Ueta2, Masaji Nishimura1; 1Department of Emergency and Critical Care Medicine, The University of Tokushima Graduate School, Tokushima, Japan; 2Medical Equipment Center, Tokushima University Hospital, Tokushima, Japan

Background: High frequency oscillation ventilation (HFOV) has recently been applied to acute respiratory distress syndrome in adults. As conventional mechanical ventilation, inspiratory gas humidification during HFOV is essential. However, humidification during HFOV for adults has not been clarified. In this bench study, we tested if humidification was affected by ventilatory settings and humidifying devices during HFOV for adults. Method: We evaluated two brands of adult HFOV ventilators: R100 (Metran, Tokyo, Japan) and 3100B (SensorMedics, Yorba Linda, CA, USA). We set a standard heated humidifier: a heated humidifier consisting of porous hollow fiber (Hummax II, Metran) for R100 and a passover-type heated humidifier (MR850, Fisher & Paykel) for 3100B. We connected each ventilator to a lung model in an incubator set at 37∞C. We measured absolute humidity and temperature at the airway opening under a variety of ventilatory settings: 3 stroke volumes /amplitudes (100, 150, and 200 mL for R100, and 30, 45, and 60 cmH2O for 3100B), 3 frequencies (5, 7, and 8 Hz), and 2 mean airway pressures (20 and 30 cmH2O). Results: The R100 ventilator showed higher absolute humidity and lower temperature than the 3100B ventilator. In the R100 ventilator, as stroke volume increased, absolute humidity and temperature became higher. As frequency increased, absolute humidity and temperature became higher. Settings of mean airway pressure did not affect absolute humidity or temperature. In the 3100B ventilator, effects of amplitude, frequency, and mean airway pressure on absolute humidity and temperature were not significant. Conclusions: Humidification during HFOV for adults was affected by stroke volume and frequency in the R100 ventilator but is not in the 3100B ventilator. Sponsored Research - None

Average absolute humidity during each condition of HFOV

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