Nowadays, the word “Corona” has become the most
prominent term in the human vocabulary, because its severity has been
responsible for the untimely end of thousands of lives throughout the world.
This pandemic disease which is also known as COVID-19, is spread by a newly discovered virus which belongs to a large family of
Coronaviruses. This disease initiates from the common cold and develop in to
Severe Acute Respiratory Syndrome (SARS). There are several stages of this
disease and at a latter part, severe damages can happen to human respiratory
system. Due to breathing difficulties, mechanical ventilation takes over the
respiration and it gives COVID-19 infected patient, time to fight against the
virus and recover. Further, in some countries, lack of mechanical ventilators
have increased the vulnerability of patients. On 19th of March 2020
Forbes, an American business magazine, had reported about a group of Italian
engineers who produced respiratory system parts using 3D printing for free, to
help keeping covid-19 patients alive. This article was inspired by the above
article. They were building venturi valves for ventilator machines with the
request of medical staff of the hospital in Chiari, in the Brescia area of
northern Italy.
Valves are essential components in many areas of engineering
and construction sectors. There are hundreds of types of valves and each functions
differently from the other. The main purpose of valves are stopping and
starting the flow, reducing or increasing a flow, controlling the direction of
flow, regulating a flow or process pressure and relieving a pipe system of a
certain pressure. When it’s narrowed down to valves functioning in mechanical
ventilators which have taken the worldwide attention due to COVID-19, mainly
there are few types. First of all, how mechanical ventilators act on an infected
patient, will help understanding the usefulness of the valves. Respiratory
system contains a series of organs which are used to exchange gasses between
human body and the environment. In severe cases of the disease, lungs are
damaged creating difficulties of breathing and oxygen level of the body is
reduced, making the situation life threatening. Ventilators push air into lungs
with increased levels of oxygen. Air and pure oxygen come through two different
tubes and mix them for a ratio which is suitable for a given patient, at a Y
junction. This is the inspiratory path. Exhaled air is collected and normalized
in the expiratory path. For some types of COVID-19 patients, ventilator is the
only way of getting oxygen into the body.
There are air flows in the process
of ventilator. So, the job of valves is important. Unidirectional valves are
used to prevent backflow through tubes and two separate valves are fitted in
inspiratory and expiratory paths. They are helpful because at some part of the
breathing circuit, the gas flow is bidirectional. Without these flow control
valves, exhaled air which contain CO2 highly can be mixed with good
quality air(Less CO2). The expiratory valve is closed during
mechanical inspiration and during the inspiratory pause if one is used. It
opens during exhalation and the further process of ventilator continues. Spool
valves are normally used as these flow control valves. A pressure relief valve
(APL valve or Adjustable Pressure Limiting valve) is used during exhalation to
drive gas to vent to atmosphere. It’s used to improve safety and is
spring-loaded or diaphragm-actuated. The pressure inside the breathing circuit
must generate a force that exceeds the compression force for the APL valve to
open. As pressure builds up from the combination of fresh gas flow and manual
compression of the breathing bag, the opening pressure of the APL valve will be
exceeded and excess gas will be vented to the scavenging system.
During such a
global issue, even the brightest mind of the planet earth, the human, has
become clueless to find an exact cure for this virus. By the time which this
article is being written (03/04/2020), 47,249 of deaths have been recorded and
there are 936,204 of positive Corona cases in the world. In Sri Lanka, to this
date there are146 positive cases and 5 of them are critical. We are a bit lucky
that only three deaths have been recorded yet but, even these three lives could
have been very important for our country’s man force. As engineers and
engineering undergraduates, what we can do in such a situation? The world has
identified the lack of mechanical ventilators and other medical equipment. In
some countries, medical equipment imports have been reduced and the demand of
machines have risen up with the high number of patients. Then the cost isn’t
easy to endure. Therefore, worldwide competition has arisen to produce low cost
ventilators and other equipment to fill the gap. Ford, GM, and other some
automakers are making low-cost, simplified versions of critical medical
equipment to aid in the coronavirus response. Engineers are leveraging their
expertise in fast manufacturing, logistics, and supply-chain operations.
Recently, a group of students in the engineering faculty, University of
Peradeniya had built up a low cost ventilator. This highlights the local as
well as global trend of engineers who are doing their duty while officers of
medical sector saving lives of people, while risking their lives. All these attempts
are to eradicate this pandemic from our planet Earth forever.
COVID-19 has threatened the entire
world irrespective of their power or wealth. The social distancing has become
the only solution for slowing down its spread. World Health Organization also
have introduced sanitary measures for people to prevent spreading the virus
because by now, it has been discovered that virus spreads primarily through
droplets generated when an infected person coughs or sneezes, or through
droplets of saliva or discharge from the nose. For protection, cleaning hands
frequently with an alcohol-based hand rub or washing them with soap and water
have been recommended. Amidst of such a situation, mechanical ventilation has
become a timely need for saving patients who suffer from this disease. As
foreign media had reported, even a small valve has mattered a lot. In the
operation of a ventilator, valves are essential as well as the good technical
knowledge to operate the machine. On this matter of COVID-19, due to the
shortage of relevant medical equipment, worldwide engineers has a prime responsibility
to strengthen their countries during this pandemic. Fruitful results have
already emerged. As an individual, we can help to reduce the spreading of the
virus by maintaining the proper social distancing and obeying health measures. Let’s
join the whole world who prays for a world without Covid-19. May all beings be healthy
and be protected from all the deadly diseases.
·
Feldman, A.,
2020. Meet The Italian Engineers 3D-Printing Respirator Parts For Free
To Help Keep Coronavirus Patients Alive. [online] Forbes. Available at: https://www.forbes.com/sites/amyfeldman/2020/03/19/talking-with-the-italian-engineers-who-3d-printed-respirator-parts-for-hospitals-with-coronavirus-patients-for-free/#5e543ebe78f1
·
“Advice for
public,” World Health Organization. [Online]. Available: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public.
·
“Ford to Produce 50,000 Ventilators in
Michigan in Next 100 Days ...”. [Online]. Available: https://media.ford.com/content/fordmedia/fna/us/en/news/2020/03/30/ford-to-produce-50-000-ventilators-in-michigan-in-next-100-days.html.
·
"VAM -
The Virtual Anesthesia Machine", Vam.anest.ufl.edu, 2020.
[Online]. Available: https://vam.anest.ufl.edu/reviewventilation.html.
·
D. Michael P.
Dosch CRNA PhD, "Anesthesia Gas Machine- Ventilators", Healthprofessions.udmercy.edu,
2020. [Online]. Available: https://healthprofessions.udmercy.edu/academics/na/agm/08.htm.
·
"Ventilator/Ventilator Support |
National Heart, Lung, and Blood Institute (NHLBI)", Nhlbi.nih.gov, 2020.
[Online]. Available: https://www.nhlbi.nih.gov/health-topics/ventilatorventilator-support.
A.W.Janani,
Undergraduate (3rd Year), Faculty of
Engineering,
University of Moratuwa
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