Personalized Ventilation to Multiple Patients Using a Single Ventilator: Description and Proof of Concept.

To design and test a ventilator circuit that can be used for ventilation of two or more patients with a single ventilator, while allowing individualization of tidal volume, fractional concentration of oxygen, and positive end-expiratory pressure to each patient, irrespective of the other patient's respiratory system mechanics. Description and proof of concept studies. Respiratory therapy laboratory. Ventilation of mechanical test lungs. Following a previously advocated design, we used components readily available in our hospital to assemble two "bag-in-a-box" breathing circuits. Each patient circuit consisted of a flexible bag in a rigid container connected via one-way valve to a test lung, along with an inline positive end-expiratory pressure valve, connected to the ventilator's expiratory limb. Compressed gas fills the bags during "patient" exhalation. During inspiration, gas from the ventilator, in pressure control mode, enters the containers and displaces gas from the bags to the test lungs. We varied tidal volume, "respiratory system" compliance, and positive end-expiratory pressure in one lung and observed the effect on the tidal volume of the other. We were able to obtain different tidal volume, dynamic driving pressure, and positive end-expiratory pressure in the two lungs under widely different compliances in both lungs. Complete obstruction, or disconnection at the circuit connection to one test lung, had minimal effect (< 5% on average) on the ventilation to the co-ventilated lung. A secondary circuit "bag-in-the-box" system enables individualized ventilation of two lungs overcoming many of the concerns of ventilating more than one patient with a single ventilator.

Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.

Dr. Mashari is a Senior Scientific Advisor (pro bono) for Glia, nonprofit company making regulatory-approved open-source medical devices. Dr. Goligher has received personal fees and research equipment and from Getinge. Dr. Kacmarek is a consultant for Medtronic on Airway Care and a consultant for Orange Med on mechanical ventilators; he received a research grant from Orange Medical for ventilator comparison. Dr. Slutsky is a consultant for Baxter and Xenios. The remaining authors have disclosed that they do not have any potential conflicts of interest.