A modification to the Maquet Flow-i anaesthesia machine for ICU ventilation

Andrew J Robinson; William London; Lazslo Kotan; Warwick Downing

Low flow not feasible for ICU. When ventilating patients for longer procedures or in an emergency and in place of an ICU ventilator, it is generally advised to run on low flows to maximise humidification. However, the first author's department has four years of experience of using the Flow-i under low flow conditions for long procedures. There is generally considerable rainout in the breathing system which requires decanting from the circuit every few hours if water buildup is not to interfere with ventilation. When wet Heat and Moisture Exchangers (HME) are less efficient at heating inspired gases, due to the energy lost to vaporizing excess water with each breath. This makes Flow-i low flow undesirable for longer term use in COVID-19, as decanting will require loss of Positive End Expiratory Pressure (PEEP) and increase potential for aerosol contamination with viral particles. Low flow also . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.