TY - JOUR T1 - Effects of a nasal high-flow system (nHF) on tidal volume, breathing rate, minute volume and I/E-ratio in healthy volunteers and patients with COPD JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p2089 AU - Jens Bräunlich AU - Marcus Köhler AU - Hans-Jürgen Seyfarth AU - Stefan Hammschmidt AU - Hubert Wirtz Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p2089.abstract N2 - Introduction: Treatment with nHF-system is able to improve symptoms of acute and chronic respiratory insufficiency. The method uses a warmed and humified high flow of air with 20-50 liter per minute (lpm). By using these devices an increase of mean pressure, pressure amplitude and a decrease in pCO2 is observable.Method: Healthy volunteers and patients with COPD were included in this study. For detection of volume changes, frequency variations and I/E-ratios we used two elastic impedance measure belts (thoracal/abdominal). The signal was relayed to a polysomnography device. Flows from 20 lpm up to 50 lpm with small, medium and large nasal prongs were tested. To compare the results with a closed ventilation support system, the measurements were also performed with CPAP (6 and 10 mbar) and BiPAP (14/6mbar). We compared the results with values measured during spontaneous breathing.Results: nHF led to a significant decrease in minute volume, tidal volume and breathing rate in healthy volunteers in comparison with spontaneous breathing. The I/E-ratio results in no significant changes. In patients with COPD the breathing rates were also decreased, but the tidal volumes were increased with partial reductions in minute ventilation. The I/E-ratio was not changed in COPD. In comparison with spontaneous breathing, CPAP and BiPAP showed significant changes in patients with COPD.Discussion: nHF resulted in significant effects on respiratory parameters of healthy volunteers and in patients with COPD. The changes deliver a possible explanation of the active manner of the breath support and the decrease in pCO2. ER -