A joint statement by the American Society of Anaesthesiologists published on March 26 advised regarding COVID-19 patients:
It is not safe to share mechanical ventilators with the current equipment.
Ventilators assist a patient to breathe by helping the lungs inhale and exhale air. These machines can be used to treat conditions such as pneumonia, stroke, and brain injury.
SARS-CoV-2 (which is the cause of COVID-19) attacks the respiratory tract. Infected patients have a compromised ability to breathe. In mild cases, breathing support or respiratory assistance can be provided by noninvasive methods, such as oxygen-rich air delivered through a mask.
When a patient is suffering from acute respiratory distress in more severe cases, invasive respiratory support may be required. Artificial airways are used to provide this support. The tube is attached to the ventilator and inserted through the mouth, nose, or throat (and down the windpipe) or a surgically made hole in the neck.
Breathe in, breathe out.
Oxygenation is the main function of a ventilation system. Ventilators are also used to remove carbon dioxide from the lungs. This is called “ventilation”.
Bag Valve Masks (BVM) are a basic ventilator. Ambu Bag or BVM is operated by manually squeezing the bladder. It is a vital tool for ambulance crews and first responders, as well as critical care units. It is lightweight, compact, and simple to use.
Mechanical ventilators can be used in situations that require a constant and controlled air exchange. These look like a quintessential medical product.
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A mechanical ventilator comprises a computerized box that sits on top of a mobile trolley. There is an array of screens, dials, data cables, power cords, and gas tubes. Modern mechanical ventilators are highly complex and sophisticated pieces of equipment. Their increased complexity, in comparison with the Ambu Bag, allows a superior level of care.
The extra features and control measures of mechanical ventilators allow adjustments such as:
Ventilators – a DIY project?
Making a mechanical ventilator requires considerable expertise in research, design, and manufacturing. To make a commercial mechanical ventilator means ensuring reliability, serviceability, and adherence to strict regulatory standards.
All of this is vital, as mechanical ventilators are often used in life-and-death situations. And this is why, like other specialist medical devices, they are not cheap. One mechanical ventilator can cost up to US$50,000 (about A$82,000).
Read more: How are the most serious COVID-19 cases treated, and does the coronavirus cause lasting damage?
Responding to a global need for mechanical ventilators, various groups from around the world have emerged with alternative ventilator designs, each claiming their design works and can be manufactured quickly and cheaply.
A number of these DIY mechanical ventilators are based on the Ambu Bag design, including open lung ventilation and proposals from Triple 8 Racing, Richard Branson’s aerospace company Virgin Orbit, and British home and garden appliance company Gtech.
However, instead of relying on manual activation like the Ambu Bag bladder, these designs use mechanical automation to press and release the bladder at desired intervals. Some basic controls are available, but the most significant advantage is their inherent simplicity.
Big players join the race.
More complex ventilator proposals have also appeared. The Mechanical Ventilator Milano (MVM) was inspired by a 1960s design and used the pressurized medical oxygen available in hospitals to drive the ventilator. This simplifies the unit considerably, as it doesn’t need a motor.
The MVM was designed by more than one hundred academics and researchers from around the world. It even features a control system enabled through wifi connectivity.
One proposal that more closely mirrors existing ventilators was developed by Dyson following an urgent request from British Prime Minister Boris Johnson, who was moved to ICU last night as he battles COVID-19. The Dyson ventilator, unsurprisingly, incorporates a motor from one of its iconic vacuum cleaners.
Read more: Who needs to be in an ICU? It’s hard for doctors to tell
Dyson is an internationally recognized design and manufacturing company. Pivoting its resources to a mechanical ventilator is not as difficult as it would be for other companies. After all, managing the movement of air is a core function of Dyson’s products (mainly vacuum cleaners, fans, and hair dryers).