The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts


Rangasamy Ramanathan2, Dave Crotwell1, Rob DiBlasi1; 1Respiratory Care/Developmental Therapeutics, Seattle Children’s Research Institute, Seattle, WA; 2Pediatrics/Division of Neonatology, LAC+USC Medical Center and Childrens Hospital, Los Angeles, CA

BACKGROUND: Nasal ventilation using nasal intermittent positive pressure ventilation (NIPPV) is on the rise in preterm infants to decrease post-extubation failures, bronchopulmonary dysplasia, and for the treatment of apnea of prematurity. NIPPV is typically applied using traditional continuous positive airway pressure (CPAP) bi-nasal short prongs. This practice can result in nasal airway tissue trauma. Nasal Cannula Intermittent Mandatory Ventilation (NC-IMV) is a novel means of delivering pressure controlled NIPPV breaths noninvasively to neonates requiring respiratory support. We have previously reported that NC-IMV is feasible and well tolerated in a large number of neonates. However, pressures or volume delivered to the patient is not known. OBJECTIVE: To determine the magnitude of pressure, volume, and positive end-expiratory pressure (PEEP) delivered to a realistic infant nasal airway/lung model using different sized nasal cannulae and at different peak inspiratory pressure (PIP) settings during time-cycled, pressure-limited mode. METHODS: We configured a neonatal test lung to simulate an apneic premature infant with compliance: 0.8 mL/cmH20 and resistance: 75 cmH20/L/sec. A realistic infant nasal airway model was attached to the test lung. The ventilator was set in IMV mode, rate 40 breaths/min, inspiratory time 0.5 s, Flow 7-9 L/min, and PEEP 5 cmH20. The nasal airway was ventilated at PIP of 10, 15, 20, 25, and 30 cmH20 using infant and intermediate high-flow nasal cannulae (Fisher Paykel, Auckland, NZ) and a new prototype nasal cannula (RAM Neotech Nasal Cannula®). Pressure, volume, and PEEP were measured in the test lung as PLUNG, VLUNG, and PEEPLUNG, respectively. RESULTS: Under all testing conditions, there was detectable PLUNG, VLUNG, and PEEPLUNG during NC-IMV. There was a linear relationship between PIP applied by the ventilator and VLUNG up to 30 cmH20. The RAM Neotech Nasal Cannula® provided greater PLUNG, VLUNG, and PEEPLUNG than the other infant nasal cannulae during NC-IMV. CONCLUSIONS: NIPPV using NC-IMV can provide a significant amount of a neonate’s volume and pressure requirements with potentially less nasal airway trauma than traditional CPAP prongs. Further studies are underway to evaluate the pressure and volume deliveries and reduction of nasal injury in spontaneously breathing neonates receiving NC-IMV support. Sponsored Research - A Prototype Cannula was provided by Neotech Medical