The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Carter Tong, Mitchell Goldstein, T. A. Merritt, Michael Terry, Elba Fayard, Richard Peverini; Neonatology, Loma Linda University ChildrenÂ’s Hospital, Loma Linda, CA

Background: Nasal Cannula has long been used to deliver flow based ventilation. As nasal cannula flow traditionally has derived from a wall flow source,, pressure propagation at the nasal interface is highly variable. More recently, nasal cannula delivery of intermittent mandatory ventilation (IMV) has been advocated. We asked whether a novel high flow nasal cannula with a larger diameter than conventional nasal cannula would be useful to deliver adequate pressure propagated ventilation using traditional IMV settings. Methods: We studied three cannula: the Preemie Ram Cannula, the Newborn Ram Cannula, and the Infant Ram Cannula. An Avea Ventilator (Viasys) in TCPL-SIMV mode was used to deliver pressures of 10/5, 15/5, 20/5, 25/5, and 30/5 with an It of 0.35s and flow 8 LPM. Leak and tube compensation were disabled. Measures of PIP propagation, volume delivery at PIP propagation and PEEP of 5 cm H2O, as well as mean airway pressure generation at the wye were recorded. Results: As shown in the chart. Conclusions: Little deviation in the mean airway pressure at the wye was noted. This indicates flow/pressure propagation to the nasal cannula and thus low resistance to flow at typical PEEP levels Volume delivery was adequate at the different levels of PIP using a back pressure of 5 cm H2O, indicating a limiting factor of I-time and not flow or pressure propagation. PIP pressures were limited to delivery at ranges from 15-18 cm H2O. At this level, resistive forces inherent to the cannula would prevent excess pressure generation at the nose. NC-IMV is feasible and efficacious with the RAM cannula. At higher levels of PIP, the cannula may be protective. Sponsored Research - None