The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Rick Carter1, Kevin Crezee1, Jeff Hoydu1, Donald Null2; 1Respiratory Care, Primary Children’s Medical Center, Salt Lake City, UT; 2Department of Pediatrics, University of Utah, Salt Lake City, UT

Background: A multicenter High Frequency Nasal CPAP (HFNCPAP) human study out of the University of Utah is due to begin in the summer of 2012. In order to prepare for this study, more in depth information was needed for volume delivery thru various nasal interfaces. Method: The Percussionaire(Sandpoint, Idaho) Sinusoidal Bronchotron with Turbohub Phasitron, Hudson( Research Triangle Park, North Carolina) Nasal CPAP Prongs (sizes 0-5) and Neotech(Valencia, California) RAM Cannulas (sizes Preemie, Newborn and Infant) were attached to TSI Certifier FA Plus(Shoreveiw, Minnesota) and then to a Infant IMTMedical Smartlung(ag, Switzerland). All prongs were sealed and pressure tested prior to testing. The lung was set at compliance of 1ml/mbar and resistance at 5 mbar/L/s. TSI Certifier transducers were zeroed and Bronchotron working pressure was set at various levels to obtain MAP’s of 6, 8, 10 and 12. Oscillatory CPAP & expiratory time set at maximum, and pulsatile flowrate & inspiratory time set to minimum thru out testing. Pulse frequency was set to minimum, 300 and maximum to investigate the effect on tidal volume(Vt) and minute ventilation(VE). Ventilator frequency was measured from 250bpm to 465bpm. At these various settings the Vt and VE were determined for various prong and cannula sizes. Results: We found that with increases in prong and cannula size that there was a mean increase in Vt and VE. We also found that Vt and VE increased as frequency decreased. The Vt ranges for Hudson prongs was 3 to 27ml and for RAM cannulas it was 2 to 21ml. Minute volume ranges for Hudson were 1.4 to 4.9L/m and RAM cannulas were .8 to 3.2L/m. We found that the conventional breath delivery had an inspiratory time of .08 to .12sec at a rate of 12bpm with peak pressures ranging from 22 to 52cm/H2O. Conclusion: The Hudson prongs performed well with the best overall results. The RAM cannulas performed adequately, but the results for Vt and VE were slightly lower than comparable Hudson sizes. Neotech recommends up to an 80% occlusion of the nares with the RAM cannulas and our testing was a 100% occlusive model, so results at manufacture recommendation may be less than we recorded. The Sinusoidal Bronchotron appears to be an effective device to provide support for high frequency nasal CPAP. HFNCPAP expands the capabilities of CPAP to influence ventilation by adding the ability to change Vt and VE delivered through the nasal prongs. Sponsored Research - None