The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

NITRIC OXIDE DELIVERY IN NEONATAL NONINVASIVE RESPIRATORY SUPPORT DEVICES.

Rob DiBlasi1,2, Dave Crotwell1, Donna Dupras1, Tara Mahaffey3, John Salyer1; 1Respiratory Care Department, Seattle Children’s Hospital, Seattle, WA; 2Center for Developmental Therapeutics, Seattle Children’s Research Institute, Seattle, WA; 3Respiratory Care Department, Harborview Medical Center, Seattle, WA

INTRODUCTION: Inhaled Nitric Oxide (iNO) is an effective pulmonary vasodilator used in intubated neonates with hypoxic lung disease. Recent evidence supports using noninvasive respiratory devices as an initial form of support and following extubation from mechanical ventilation. However, there are no data describing the effects of iNO delivery using these devices. We conducted a descriptive bench study to evaluate: 1) stability of lung model parameters, 2) Nitrogen Dioxide (NO2) and 3) NO levels in a neonatal lung model with all different types of neonatal noninvasive respiratory support. METHODS: A realistic infant nasal airway model was attached to a spontaneously breathing lung model (ASL 5000, Ingmar Medical) with RR 40, Pes 12, R: 25 cmH2O/L/s, and C: 2 mL/cmH2O. A KMNO_4 and charcoal filter was placed at the lung model to scrub iNO and eliminate rebreathing of NO. Each of the noninvasive respiratory support devices (see Table) were attached to the lung model and baseline pressures and volumes were recorded. The INOmax DS (Ikaria, Seattle) was attached and tracheal NO (chemiluminescent sensor), INOmax DS NO and NO2 levels were measured between the filter and nasal airway model while adjusting the preset iNO level between 5, 20, and 40 ppm. Lung model parameters were also measured simultaneously at each of the iNO settings (n=40 breaths). RESULTS: Neither gas sampling nor the addition of iNO had any effect on the measured volume nor pressure within the lung model under any of the testing conditions. There were no clinically relevant differences between the pre-set iNO level and those measured in the simulated neonatal trachea using all forms of support but the HFNC. In all HFNC testing conditions where iNO was used, the NO levels measured by the INOmax were similar to the preset values but tracheal NO was approximately 50% of the pre-set iNO value. The NO2 levels were = 2 ppm for all testing conditions. DISCUSSION/CONCLUSIONS: Accuracy and potential safety of iNO therapy appears to be sufficient when using FDA approved noninvasive “pressure” devices; however, accuracy is compromised when using high flow nasal cannula. We believe this is related to the leaky nature of this nasal airway interface which can result in air entrainment and dilution of the iNO dose. Sponsored Research - This study was funded by a grant from Ikaria