Miniature Transport Respirator Performance Evaluation for Ventilatory Support

Abstract

In the face of the coronavirus pandemic (COVID-19), in hospital and emergency units, there is low availability of mechanical respirator for patients in need of this support, greatly improving the survival rate. In these situations, there is a need for simpler equipment, easy access, low cost, and fast manufacturing. In this study, a 3D prototype transport respirator was developed using as a model the Takaoka 600 Mini Respirator, national technology from the 1950s. The influence of adjustable parameters of the respirator was evaluated to understand it is functioning: maximum and minimum lung pressure; respirator intake pressure; respiratory rate; inspiratory and expiratory time according to the sensitivity of the mini respirator; and pressure and flow of O₂ line intake. The increase in sensitivity led to an increase in maximum and minimum pulmonary pressure, decreased inspiratory and expiratory time, with margins of 1/1, 1/2, 1/3 inspiratory/expiratory time ratio (I/E ratio). The intake flow of O₂ varied proportionally with the pressure of air intake into the respirator, with its increase leading to an increase in respiratory rate, without major influences on lung pressure and the I/E ratio. The O₂ line intake pressure without major influences on lung pressure, showing and I/E ratio >1 in values below 3.5 kPa x 100. In conclusion, it was possible to obtain a pulmonary ventilator-dependent only on positive O₂ flow, compact and effective for patient transport, and in cases of emergencies with control of maximum pressure and respiratory rate offered to the patient. Among the parameters evaluated for this respirator, an line pressure of O₂ from 3.5 kPa x 100, sensitivity between 3 and 5, a flow of 5 to 15 L/min is recommended.