TY - JOUR T1 - Flow, leakage or pressure – Who determines the clinical consequences of the nasal high– Flow (nHF)? JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P4704 AU - Jens Bräunlich AU - Friederike Goldner AU - Hans-Jürgen Seyfarth AU - Hubert Wirtz Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P4704.abstract N2 - Introduction: The nasal high flow (nHF) becomes more and more acceptance in particular in breathing support of children and neonates. However, also with adults there is already a number of interesting knowledge. nHF is able to reduce hypercapnia in patients with COPD and IPF. Nevertheless, the active mechanism is not exactly understood yet.Method: Patients with COPD were applied nasal high-flow 1 hour under BGA control. Besides, the following combinations were measured:a. 20 l/min, 2 prongs, both prongs openb. 40 l/min, 2 prongs, both prongs openc. 40 l/min, 2 prongs, both prongs open, 1 prong in nose, 1 prong outsided. 40 l/min, 2 prongs, 1 prong open, open prong in nose, the closed prong outsideThe pressure ratios were measured, in addition, in the hypopharynx.Results: Differences appeared between the different seetings. A) led to the slightest decrease in pCO2. B) reached the highest airway pressure. C) led to the strongest decrease in pCO2.Discussion: From the investigations it arises that the increase of the airway pressure is not the dominating size in nHF. Enlargement of the leakage (wash-out) and increases of the flow speed maximizes the effects. This can be read in clearly better dropping pCO2. ER -