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COBEM 2021
26th International Congress of Mechanical Engineering
AN ALTERNATIVE VENTILATOR PROTOTYPE FOR THE EMERGENCY SITUATION DUE TO COVID-19 PANDEMIC
Submission Author:
João Paulo Fonseca , GO
Co-Authors:
João Paulo Fonseca, Felipe Pamplona Mariano, André Luiz Franco, Anderson Girardi, Sigeo Kitatani Júnior
Presenter: João Paulo Fonseca
doi://10.26678/ABCM.COBEM2021.COB2021-1514
Abstract
The pandemic caused by the SARS-COV-2 virus, called coronavirus disease 2019 (COVID-19), had an unexpected impact around the world, especially in Brazil. People diagnosed with the virus have different levels of respiratory symptoms and may need mechanical ventilation support. In this pandemic scenario, the demand for artificial pulmonary ventilation equipment increased according to the evolution of the disease, becoming a critical factor for the functioning of the intensive care units. A pulmonary mechanical ventilator (PMV) consists of an equipment capable of delivering air and / or oxygen, named fraction of inspired oxygen (FiO2), in a controlled manner for patients with severe acute respiratory syndrome (SARS). Among the various requirements that this device must meet, the following stand out: monitoring control, alarms for adverse events and adjustments to ventilatory parameters, like FiO2, respiratory rate, positive end-expiratory pressure (PEEP), inspiration volume and pressure, sensitivity, among others. In this sense, the objective of this study is discussing the development and evaluation of an alternative PMV prototype, inspired on the mandatory functional characteristics indicated by technical notes published by the Brazilian Intensive Care Association (AMIB) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Due to the lack of clinical material, the prototype development uses accessible and industrially widespread equipment, like pneumatics directional control valves, pressure valves, pipes, and fittings, meshed with available clinical ones. The volume control ventilation mode was performed using programmable logic controller (PLC) and an industrial-kind human machine interface, with lcd touch screen, as interface for the clinical operator. By using a parallel mounting of three inspiration valve, each one calibrated for a specific flow, a set of seven options for inspiration flow adjustment was available. Critical variables like lung pressure were acquired using gauge and differential pressure sensors, and a printed circuit board for signal conditioning providing a standard 0-10V signals for the PLC analog inputs. Inspiratory flow was estimated using an orifice plate method, reaching a discharge coefficient above 0.92. Preliminary tests were performed using an artificial lung under different conditions of complacency and resistance, while the respiratory mechanics data was evaluated by a commercial gas flow analyzer. Finally, for instance, the alternative PMV prototype was evaluated in a pre-clinical test applied to porcine, whose satisfactory results were recently published in another periodical paper.
Keywords
mechanical systems design, biomedical equipment, fluid power systems, medical control systems, programmable logic controller
