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Flows and function of the Infant Flow neonatal continuous positive airway pressure device investigated with computational fluid dynamics
Author(s) -
Drevhammar Thomas,
Berg Niclas,
Nilsson Kjell,
Jonsson Baldvin,
Prahl Wittberg Lisa
Publication year - 2021
Publication title -
acta paediatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/apa.15502
Subject(s) - mechanics , flow (mathematics) , medicine , large eddy simulation , breathing , computational fluid dynamics , jet (fluid) , entrainment (biomusicology) , physics , anesthesia , turbulence , rhythm
Abstract Aim The first dedicated neonatal continuous positive airway pressure (CPAP) device using variable flow was the Infant Flow. The system was pressure stable with a low resistance to breathing. The aim of this study was to describe the flow and function of the Infant Flow geometry using simulated breathing and computational fluid dynamics. Method The original Infant Flow geometry was used with simulated term infant breathing at three levels of CPAP. The large eddy simulation methodology was applied in combination with the WALE sub‐grid scale model. Results The simulation fully resolved the flow phenomena in the Infant Flow geometry. The main flow feature during inspiration was support by gas entrainment and mixing. During expiration, the jet deflected towards the outlet with unstable impingement of the jet at the opposing edge. Conclusion The proposed mechanism has previously been based on theoretical reasoning, and our results present the first detailed description of the Infant Flow. The pressure stability was based on a jet supporting inspiration by gas entrainment and then being deflected during exhalation. This confirmed previously assumed principles of function and flows within the geometry and provided a base for further developments.