Electronic Computer-Based Model of Combined Ventilation Using a New Medical Device

Ramos, M.; Orofino, R.; Riva, D.; Biancolini, M. F.; Lugones, I.

Introduction: The increased demand for mechanical ventilation caused by SARS-CoV-2 could generate a critical situation where patients may lose access to mechanical ventilators. Combined ventilation, in which two patients are connected to a single ventilator has been proposed as a bridge while waiting for new ventilators availability. DuplicAR is a new device that allows individualization of ventilatory parameters in combined ventilation models. Materials and Methods: With an electronic circuit simulator applet, an electrical model of combined ventilation was created using resistor-capacitor circuits. The DuplicAR system electrical analog was added to the model. Through computational simulation, the model is tested in different scenarios with the aim of achieving adequate ventilation of two subjects under different circumstances: 1) two identical subjects; 2) two subjects with the same size but different lung compliance; and 3) two subjects with different size and compliance. The goal is to achieve the established load per unit of size on each capacitor under different levels of end-expiratory voltage (analog of end-expiratory pressure). Data collected included capacitor load and voltage, and load normalized to the weight of the simulated patient. Results: In the three simulated stages, it is possible to provide the proper load to each capacitor under different circumstances. If the pair of connected capacitors have different capacitances, adjustments must be made to the source voltage and/or the resistance of the DuplicAR system to provide the appropriate load for each capacitor under initial conditions. In pressure control simulation, increasing the end-expiratory voltage on one capacitor requires increasing the source voltage and the resistance on the other capacitor. On the other hand, in the volume control simulation, it is only required to intervene in the resistance. Conclusions: Under simulated conditions, the electrical model of the DuplicAR system allows individualization of combined mechanical ventilation.