Purpose
It is now clear that the COVID-19 viruses can be transferred via airborne transmission. The objective of this study was to attempt the design and fabrication of an AMBU ventilator with a negative pressure headbox linked to a negative pressure transporting capsule. This could provide a low-cost construction, flexible usage unit, and also airborne prevention that could be manufactured without a high level of technology.
Method
The machine consists of an automated AMBU bag ventilator, a negative pressure headbox, and a transporting capsule. The function and working duration of each component were tested.
Automated AMBU bag Ventilator
Oxygen within a pipeline or a tank initially passes through an air filter and then into the ventilating system. A 12 V DC brushless motor for medical equipment, max power consumption 18 W, was used as a blower motor. To control flow rate, rhythm, and volume of oxygen, three electrical circuits, including, a speed control circuit, a timer circuit, and a battery protection circuit, were incorporated with the blower. A pressure release valve, set to operate if the air pressure exceeds 40 cm H2O, was fitted to the AMBU bag. A 12 V 2.3 Ah rechargeable sealed lead-acid battery was used as the main power supply. A mechanical ventilator prototype is shown in Figure 1.
Negative Pressure Headbox and trasporting capsule
The headbox, which was mainly made of a PVC transparent sheet 0.5 cm thickness, was used as air-borne protective equipment. Four waterproof zippers were amalgamated with the headbox for hand and/or tube insertion. All components of the headbox, except the HEPA filter, can be cleaned by any disinfectants.
Results
The two main settings of the ventilator include an active mode that can be set at the time range of 0 s–9h 59 min 59 s and a resting mode, which could work continuously for 24 h. The blower motor and battery system, create negative air pressure within the head- box, and the transporting capsule, could run for at least The combination of an automated AMBU ventilator with a negative pressure headbox is shown in Figure 2.
Similar to the negative pressure headbox, a semi-circular cylindrical transporting capsule, measuring 0.28 m3 in volume, which is shown in Figure 3, was made of PVC materials and waterproof zippers. 2 h without being recharged. The transporting capsule was able to create an air change rate of 21.76 ACH with-10 Pa internal pressure. Further development of this machine should focus on how to link seamlessly with imaging technology and then test using human subjects before commercialization.
Source: Front. Robot. AI, 29 January 2021 | https://doi.org/10.3389/frobt.2020.621580
Author: Arnon Jumlongkul, School of Medicine, Mae Fah Luang University, Thailand.
