Pressure and Volume Control in a new Emergency Mechanical Ventilator based on PLC and Industrial Pneumatic Parts in Peru

Abstract

This work details a methodology of design and test of a new prototype emergency mechanical ventilator called Fenix for the COVID-19 crisis in Peru. This equipment was manufactured with industrial equipment for the embedded and pneumatic systems, such as a Programmable Logic Controller (PLC), proportional flow valves, sensors, uninterruptible power supply (UPS), industrial panel HMI 15 and other electrical and pneumatic parts from Festo and Schneider Electric. This selection was in accordance with safety requirements based on ISO 80601-2-12: 2020-02. This study included two ventilatory modes, pressure- controlled in continuous mandatory ventilation (PC-CMV) and volume-controlled in continuous mandatory ventilation (VC-CMV), these control algorithms were evaluated analytically and experimentally in a FLUKE VT-650 Gas Flow Analyzer and an Acculung Fluke connected with a computer for comparing 9 ventilatory parameters in 4 different states as μ, simulation of the variation of the pressure control in a patient, and Θ, simulation of alveolar recruitment in an intensive care patient, both states to PC-CMV, and also β, simulation of the variation of the flow control in a patient, and α, simulation of alveolar recruitment in an intensive care patient, both last states to VC-CMV. Additionally, we study the pressure, volume, and flow graphs in the Fenix user interface for comparison with data recovered from Fluke Medical VT650 Gas Flow Analyzer. The results demonstrate an error in the flow measurement for the 4 states due to the peaks that are not detected by the low-pass filter of the sensor, however, a similar trend is seen in the control ventilatory graphs of the calibrator. Finally, the ventilator prototype provides ventilatory support, with a maximum tidal volume error of 12.93 % and inspiratory pressure of -20.15 % with respect to the set value; and it allows to monitor the main ventilation parameters with a calculation error between -6 to 25 %.Clinical Relevance - Established the design of emergency mechanical ventilator using PLC and industrial components.