@article {MazmanyanP3299, author = {Pavel Mazmanyan and Mari Darakchyan and Sheng Feng and Stanislav Tatkov}, title = {Breathing dynamically changes positive airway pressure during nasal high flow in neonates}, volume = {44}, number = {Suppl 58}, elocation-id = {P3299}, year = {2014}, publisher = {European Respiratory Society}, abstract = {Introduction: Nasal High Flow (NHF) generates positive airway pressure in spontaneously breathing patients. The aim of the study was to investigate intranasal flow/pressure changes during NHF in neonates.Methods: Nasal pressure was measured in 6 (3M/3F) near term premature newborns (mean gestation age of 35.8 (SD 2.2) wk and mean birth weight of 2516.6 (SD 443.4) g that received respiratory support. NHF at 5L/min and 10L/min were generated by an AIRVO 2 (Fisher \& Paykel Healthcare, NZ). Flow-pressure profile in both nasal cavities was obtained from respiratory inductance plethysmography and manometry with two micro pressure probes.Results: Measured PEEP varied in both nasal cavities (Fig 1a). Magnitude of pressure at any given NHF was modulated by the respiration cycle - increasing during expiration and decreasing during inspiration (Fig 1b). Inspiratory pressure remained positive during NHF 5 and 10 L/min.Conclusion: Intranasal pressure dynamically changes according to the breathing cycle and may vary in both nasal cavities. Peak inspiratory and expiratory pressure values depend on peak inspiratory and expiratory flow and need to be analysed along with PEEP for interpretation of delivered pressure during NHF therapy.Fig 1 (a) Box-whisker plot (5-95\% CI) of PEEP generated by 10L/min, 5L/min NHF and control.(b) An example of flow-pressure profile.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/44/Suppl_58/P3299}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }