Mario Bahbouh
This quarantine has been hard on all of us with varying degrees. While we struggle to find any motivation to continue on with our lifestyle, it maybe important to realize that we are doing this for a reason and a purpose.
By staying at home and abiding by the rules and regulations of the quarantine, we are providing a fighting chance to those affected by the pandemic all around the world. This article is about another group of people who are trying to help the medical community with the weapons necessary to overcome this battle.
Last week I was able to talk to a close friend of mine, George Felobes, an engineering student in Canada who told me about this interesting project he’s working on with a group of engineers to help with the struggle of finding enough ventilators to go around fort the patients affected by the pandemic.
The Ventilators Problem
SARS-CoV-2 has no official treatment or vaccine; patients of the virus are instead treated for Acute Respiratory Distress Syndrome, ARDS. Treatment involves continuous ventilation. According to multiple reports from various Italian hospitals, a lot of attention has been directed towards “increasing the number of beds, ventilators and intensive care units”.
Multiple reports have indicated that COVID-19 patients demonstrate an atypical form of ARDS, one with good lung compliance, in terms of gas volume, accompanied with severe hypoxemia, low O2 levels in the blood. With the pandemic virus catching us off guard the equipment necessary to provide ventilation is quickly becoming scarce.
Normal Ventilators
Ventilators aim to step in and replace normal lung ventilation by mechanical means due to the failure of normal lung function. Two types of ventilation are present; mechanical, an invasive method requiring airway tubes, and the second is a non invasive method, with a face mask covering the nose and mouth instead.
Two techniques are commonly used to provide adequate oxygenation to the patient during the process. The first is Positive End Expiratory Pressure, PEEP, used in conjunction with mechanical ventilation, exerting pressure to oppose the passive emptying of the lung.
The other technique is Prone Positioning, a maneuver performed where patients are placed in the prone position, flat on their chests, and an improvement of 70-80 % in the patient’s oxygenation is seen. The physiological and clinical benefits of Prone Positioning remain unknown.
The Suggested Solution
Engineers from the University of Calgary, have been working on a design for low-cost portable ventilators. Based on designs from the “Iron Lung” model used during the Polio outbreak, it consists of a Pressure Chamber surrounding the patient, a Pressure Sink and a Control System.
Pressure Chambers come in two forms; Cuirass NPV and a “Poncho” or “Jacket”, which envelopes the patient providing the pressure required to perform artificial ventilation. Cuirass NPV systems resemble a metal jacket that surrounds the patient and although it offers a lighter, more portable solution compared to previous versions of the “Iron Lung” model, it is subject to chaffing at seals and reduced efficacy as a result.
The “Poncho” design is cheaper and allows for more flexibility and a quick entry in case of emergency along with the quickest manufacturing process, as duct tape is adequate enough to seal the chamber.
The second component is the Pressure Sink providing the -50 to 60 cm H2O pressure required. This mechanism is similar to your average household vacuum cleaner, applied continuously. Engineers aim to have an easy way to turn on the ventilator but make it harder to turn it off, a visible way to demonstrate its failure and most importantly the ability to survive a power outage.
Finally the Control System is responsible for setting case-specific parameters including the level of negative pressure and its duration and the cycle time. It is also responsible for the opening of ‘bleeding valves’ to release some pressure allowing “multiple patients to be ventilated quickly using a shared, manually operated system until an automated solution can be arranged.”
It is of the utmost importance that the energy and resources available to the researchers be directed towards producing these low- cost ventilators because they are deemed as a necessity right now in fighting the pandemic.
The research remains in its early stages and many engineers fear that the design for these new ventilators is based on the very outdated design of the “Iron Lung” model. Despite that researches in the University of Calgary remain adamant that with their proposed tweaks and changes, they will be able to provide a functioned low cost ventilator soon and be able to employ in countries that have been severely affected by the pandemic.
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