Oxygen Delivery Devices: The FiO2 Physics | Pulmonics 29/100

One mass-balance equation explains every oxygen device: why a nasal cannula's FiO₂ falls as the patient breathes harder, how an air-entrainment mask sets its ratio and total flow, why a large-volume nebulizer dialed above about 60% gains almost no oxygen, and how to pick and troubleshoot the right device. Taught by Kasim Hassen, MD, RRT. Part of Pulmonics — respiratory care from first principles. Chapters 0:00 Hook 0:44 Objectives 1:22 Who supplies the breath 2:23 The mixing equation 3:23 Why harder breathing dilutes the cannula 6:05 Air entrainment — the ratio from mass balance 7:56 Does the total flow meet the demand? 9:52 The large-volume nebulizer ceiling 11:37 Masks with and without a reservoir 13:18 Selecting and troubleshooting 14:47 Both Sides of the Bed 15:44 Board traps 17:05 Case resolved and recap 17:49 Recall questions 18:28 Next References (abbreviated; full citations on request) 1. Bazuaye EA et al. Thorax 1992. doi:10.1136/thx.47.8.609 2. Katz I et al. Respir Res 2019. doi:10.1186/s12931-019-1104-0 3. Sabz M et al. Respir Care 2024. doi:10.4187/respcare.11438 4. Li J et al. Ann Intensive Care 2021. doi:10.1186/s13613-021-00949-8 5. Zhou S et al. Respir Care 2014. doi:10.4187/respcare.02878 6. Wettstein RB et al. Respir Care 2005 7. Markovitz GH et al. Respir Care 2010 8. Scacci R Respir Care 1979. doi:10.1177/002013247902401007 9. O'Driscoll BR et al. Thorax 2017. doi:10.1136/thoraxjnl-2016-209729 10. Canet J et al. Eur J Respir Dis 1984 11. Wagstaff TA et al. Anaesthesia 2007. doi:10.1111/j.1365-2044.2007.05026.x 12. Foust GN et al. Chest 1991. doi:10.1378/chest.99.6.1346 13. Jensen AG et al. Acta Anaesthesiol Scand 1991. doi:10.1111/j.1399-6576.1991.tb03291.x 14. Barnett A et al. Respirology 2022. doi:10.1111/resp.14218 15. Duprez F et al. Respir Care 2022. doi:10.4187/respcare.09312 16. Piraino T et al. Respir Care 2022. doi:10.4187/respcare.09294 17. National Oceanic and Atmospheric Administration et al. 1976. https://ntrs.nasa.gov/citations/19770... 18. National Board for Respiratory Care 2027. https://www.nbrc.org/wp-content/uploa... Educational content only — not medical advice for any individual patient.