When Resources Are Scarce - Feasibility of Emergency Ventilation of Two Patients With One Ventilator

Peter C. Reinacher; Thomas E. Schlaepfer; Martin A. Schick; Juergen Beck; Hartmut Buerkle; Stefan Schumann

The two compartments of a physical model (Dual Adult Ventilator Tester, Michigan Instruments, Grand Rapids, MI) were considered representing resistance and compliance of the independent respiratory systems of two patients, mechanically ventilated via one intensive care ventilator (Evita XL, Dräger medical, Lübeck, Germany). To connect both patients to one ventilator we applied two simple straight polyoxymethylene adaptors of 22 mm (equivalent to 0.866 in) inner diameter ( Figure 1 ) to link the ventilator's inspiratory and expiratory out-and inlet to Y-pieces which on their part connected two respiratory tubing systems with the ventilator. Each of the tubing systems was connected to the patient model via an endotracheal tube of 7.0 mm inner diameter (Mallinckrodt, Hi-Contour, Covidien, Dublin, Ireland). In our experiments we investigated all possible combinations of respiratory system compliances of 30, 40, 50 and 60 ml/cmH2O. Every combination was investigated as follows: first, the respective compliance of each compartment was set independently. Then they were connected collectively to the ventilator. Pressure controlled ventilation was started with PEEP 14 cmH20, which is part of the treatment standard of SARS-COV-2 ARDS in our facility. Ventilation frequency was set to 18 breaths per minute and peak pressure was set to generate a tidal volume of 850 to 1000 ml, corresponding to a tidal volume of 5.7 to 6.7 ml/kg for a patient of 75 kg body weight. Since peak . CC-BY-NC-ND 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.