The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Darrin Bosquet, Craig D. Smallwood; Respiratory Care, Childrens Hospital Boston, Boston, MA

BACKGROUND: Non-invasive ventilation (NIV) is commonly used to treat respiratory insufficiency in pediatric patients. The purpose of this study was to determine the variability of fractional inspired oxygen concentration (FiO2) during simulated NIV use. METHODS: A bench model was constructed to test the performance of the V60 ventilator (Philips Respironics, Andover, MA). The single limb V60 ventilator circuit was connected to a pediatric test lung. FiO2 measurements were made with the GE Datex Ohmeda Compact Monitor with E-COVX gas module (GE Healthcare, Madison, WI) connected in-line between the ventilator circuit and test lung. FiO2 was recorded during biphasic positive airway pressure (BiPAP) ventilation. The inspiratory pressure was varied in order to ascertain the effect of inspiratory flow rate on FiO2 variability. All data was recorded using S5 Collect 4 and converted to MS Excel for analysis. The mean, standard deviation and range was calculated for each set FiO2. RESULTS: Please see table. All results are expressed as FiO2 percentage. CONCLUSIONS: Changes in inspiratory flow rates did not significantly affect the FiO2 variability. The greatest variation in oxygen delivery was found at 50%. Stable FiO2 delivery was apparent at all other levels tested. Because these data were not collected during clinical use of the device, our study is somewhat limited. Carbon dioxide rebreathing could be present during clinical application of non-invasive ventilation and would cause fluctuations in FiO2 regardless of ventilator performance. Further study investigating this phenomenon during pediatric NIV use may be necessary. FiO2 variation data during NIV may help future researchers develop means of accurate inspired and expired gas analysis. Applications could include oxygen cost of breath and indirect calorimetry. Sponsored Research - None