title: Gas transfer model to design a ventilator for neonatal total liquid ventilation.
abstract: The study was aimed to optimize the gas transfer in an innovative ventilator for neonatal Total Liquid Ventilation (TLV) that integrates the pumping and oxygenation functions in a non-volumetric pulsatile device made of parallel flat silicone membranes. A computational approach was adopted to evaluate oxygen (O2) and carbon dioxide (CO2) exchanges between the liquid perfluorocarbon (PFC) and the oxygenating gas, as a function of the geometrical parameter of the device. A 2D semi-empirical model was implemented to this purpose using Comsol Multiphysics to study both the fluid dynamics and the gas exchange in the ventilator. Experimental gas exchanges measured with a preliminary prototype were compared to the simulation outcomes to prove the model reliability. Different device configurations were modeled to identify the optimal design able to guarantee the desired gas transfer. Good agreement between experimental and simulation outcomes was obtained, validating the model. The optimal configuration, able to achieve the desired gas exchange (ΔpCO2 = 16.5 mmHg and ΔpO2 = 69 mmHg), is a device comprising 40 modules, 300 mm in length (total exchange area = 2.28 m(2)). With this configuration gas transfer performance is satisfactory for all the simulated settings, proving good adaptability of the device.
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Bonfanti
authors.affiliation: Department of Energy, Nuclear Engineering Division (CeSNEF), Politecnico di Milano, Via Lambruschini 4, 20156 Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cammi
authors.affiliation: Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy. Electronic address: paola.bagnoli@polimi.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Bagnoli
mesh_terms: D002138:Calibration; D002245:Carbon Dioxide / Q000737:chemistry*; D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D057446:Hydrodynamics; D007231:Infant, Newborn; D021061:Liquid Ventilation / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000737:chemistry*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Gas exchange; Neonatal ventilator; Numerical model; Perfluorocarbon; Total liquid ventilation