The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Keith R. Hirst1, Girmachew Mekonnen1,2, David Shelledy1; 1Respiratory Care, Rush University, College of Health Sciences, Chicago, IL; 2Respiratory Care, University of Illinois Medical Center, Chicago, IL

INTRODUCTION: the MISTY OX® high FIO2-high flow nebulizer (Cardinal Health, Dublin OH) was developed to overcome shortcomings of conventional air-entrainment devices. The MISTY OX® is designed to deliver FIO2’s from 0.60 to 0.96 with total gas flows from 42 to 80 L/min. We sought to determine the actual delivered FIO2 when using the MISTY OX® via aerosol mask in normal subjects. METHOD: Following informed consent, 10 healthy volunteers had an 8 French catheter inserted with the tip positioned immediately behind the uvula and secured to the nare by tape. Subjects were placed on a MISTY OX® High FIO2-High Flow Nebulizer connected to large bore tubing and an aerosol mask. Oxygen therapy was set at an FIO2 of 0.60, 0.75 and 0.96 with the flow meter set at 40 L/min for a period of 5 minutes at each setting. With the subjects breathing normally, gas samples were analyzed from three sites: the MISTY OX® nebulizer outlet, subject’s lip and from the subject’s pharynx using a calibrated oxygen analyzer. The mean and standard deviations were calculated from all samples. RESULTS: Gas samples from the 0.60 and 0.96 were lower in the pharynx then what was set on the MISTY OX® but was equal from 0.75. Samples from the nebulizer output and mask were lower from 0.60 and 0.96, however were higher in 0.75. CONCLUSION: Actual delivered FIO2 when using the MISTY OX® nebulizer can vary considerably from the set value. Care should be taken when interpreting patient response to oxygen therapy when using this device as actual FIO2 may be less than set FIO2. Sponsored Research - None