662 - Evaluation of Pressure Delivery by Heated, Humidified, High Flow Nasal Cannula in an Artificial Neonatal Airway Model

Poster Number: 662
Publication Number: 662.442

Amy F. Miner, Rutgers RWJMS Neonatal Fellowship, New Brunswick, NJ, United States; Lonnie Miner, Intermountain Health, Cottonwood Heights, UT, United States; Shane Cheney, Primary Children's Hospital, Pine Canyon, UT, United States; Bradley A. Yoder, University of Utah School of Medicine, Salt Lake City, UT, United States

Background: CPAP is the accepted standard for neonatal non-invasive respiratory support, but traditional nasal prongs or masks are cumbersome and difficult to manage. Alternative non-invasive systems allow for more comfort and ease of use, but pressure delivery is not well known.

Objective: The purpose of our study was to evaluate the delivery of PEEP across two Heated, Humidified, Hight Flow Nasal Cannula systems (HFNC) using common clinical settings.

Design/Methods: Delivered PEEP was measured via a 3-D model based on a 750 g neonate utilizing a pressure sensor and generated wave forms (Baby LIV, Fisher-Paykel). We used two standard HFNC systems: 1) Optiflow using the Optiflow Jr 2 small cannula (Fisher-Paykel) and 2) Precision Flow system using both the Premature and the Neonatal cannula (Vapotherm). Flows of 1-15 LPM were provided in 1 LPM increments for the Optiflow interface and 1-8 LPM (the maximum range allowed) for both Vapotherm interfaces. Each waveform was analyzed for average delivered PEEP and oscillatory characteristics.

Results: Variation in delivered PEEP was noted at the same flow between the three interfaces. All showed minimal distending pressures at flows from 1 to 5 LPM. At flows from 6-15 LPM the Optiflow Jr small cannula delivered PEEP ranging from 2.9 to 7.35 cm H2O. With the small cannula there was a diminishing increase of PEEP with flow above 9 LPM. The Precision Flow system delivered increasing pressures from 6 to 8 LPM with the Premature cannula lower than the Neonatal cannula (1.98 to 3.59 vs 2.67 to 4.44 cm H2O respectively). Both the Premature and Neonatal cannula showed evidence of a mild oscillatory effect not noted with the Optiflow Jr.

Conclusion(s): In this 750 g bench model, standard high flow nasal cannula delivered a consistent level of PEEP in a flow dependent manner. The Optiflow Jr system via small cannula delivered highest distending pressures, followed by the Precision Flow system using the Neonatal cannula. Distending pressures with the Premature cannula were < 4 cm H2O at all flow rates. Interestingly, the Precision Flow system demonstrated a mild oscillatory waveform effect. Further clinical evaluation is warranted to determine the efficacy of each interface.