caa a22 4500 46573961X CHVBK 20180323111805.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF02368418 doi (NATIONALLICENCE)springer-10.1007/BF02368418 Studies of wall shear and mass transfer in a large scale model of neonatal high-frequency jet ventilation [Elektronische Daten] [W. Muller, S. Gerjarusek, P. Scherer] The problem of endotracheal erosion associated with neonatal high-frequency jet ventilation (HFJV) is investigated through measurement of air velocity profiles in a scaled up model of the system. Fluid mechanical scaling principles are applied in order to construct a model within which velocity profiles are measured by hot-wire anemometry. The effects of two different jet geometries are investigated. Velocity gradients measured near the tracheal wall are used to measure the shear stresses caused by the jet flow on the wall. The Chilton-Colburn analogy between the transport of momentum and mass is applied to investigate tracheal drying caused by the high shear flow. Shear forces are seen to be more than two times higher for jets located near the endotracheal tube wall than for those located axisymmetrically in the center of the tube. Since water vapor fluxes are dependent on these shears, they are also higher for the asymmetric case. Fluxes are shown to be greatly dependent on the temperature and relative humidity of the inspired gas. Water from the tracheal surface may be depleted within one second if inspired gases are inadequately heated and humidified. It is recommended that the design of neonatal HFJV devices include delivery of heated (near body temperature), humidified (as close to 100% humidity as possible) gases through body temperature), humidified (as close to 100% humidity as possible) gases through an axisymmetric jet to best avoid the problem of endotracheal erosion. Pergamon Press plc, 1990 Velocity profile nationallicence Hot-wire anemometry nationallicence Mass and momentum transfer analogy nationallicence Jet location in endotracheal tube nationallicence Muller W. Department of Bioengineering, University of Pennsylvania, 220 S. 33rd St., Towne Building, 19104-6392, Philadelphia, PA aut Gerjarusek S. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA aut Scherer P. Department of Bioengineering, University of Pennsylvania, 220 S. 33rd St., Towne Building, 19104-6392, Philadelphia, PA aut Annals of Biomedical Engineering Kluwer Academic Publishers 18/1(1990-01-01), 69-88 0090-6964 18:1<69 1990 18 10439 https://doi.org/10.1007/BF02368418 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02368418 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Muller W. Department of Bioengineering, University of Pennsylvania, 220 S. 33rd St., Towne Building, 19104-6392, Philadelphia, PA aut NATIONALLICENCE 700 1- Gerjarusek S. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA aut NATIONALLICENCE 700 1- Scherer P. Department of Bioengineering, University of Pennsylvania, 220 S. 33rd St., Towne Building, 19104-6392, Philadelphia, PA aut NATIONALLICENCE 773 0- Annals of Biomedical Engineering Kluwer Academic Publishers 18/1(1990-01-01), 69-88 0090-6964 18:1<69 1990 18 10439 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer