Differential ventilation using flow control valves as a potential bridge to full ventilatory support during the COVID-19 crisis

Matthew Levin; Martin D Chen; Anjan Shah; Ronak Shah; George Zhou; Erica Kane; Garrett Burnett; Shams Ranginwala; Jonathan Madek; Christopher Gidiscin; Chang Park; Daniel Katz; Benjamin Salter; Roopa Kohli-Seth; James B Eisenkraft; Suzan Uysal; Michael McCarry; Andrew B Leibowitz; David L Reich

Opportunity for ventilation can be increased if ventilator sharing can be safely utilized. The concept of ventilator sharing is not new, and simulated ventilator sharing has been previously described. 9-12 However, the only report that describes the use of a valve in a breathing circuit to achieve differential lung ventilation in clinical practice was in a single patient. 13 At least one recently published protocol provides guidance on shared ventilation, but it has limitations. 6 Differential ventilation using one ventilator and a split circuit with flow control valves adequately addresses all of the concerns expressed in the consensus statement that recommends against shared ventilation (see Appendix) and has advantages over previous protocols. The adjustable flow valves allow the pressure and volume delivered to each patient to be continuously individualized and titrated to changes in compliance. Appropriately-placed spirometry sensors enable accurate measurement of the delivered tidal volume, airway pressure, compliance, and end-tidal CO 2 for each patient individually. These data can be displayed on a wall-mounted or portable monitor. The unidirectional valves in both the inspiratory and expiratory limbs prevent reverse gas flow in the circuits or mixing of breathing gas between patients.