A loud, clear call rang out in the early days of the novel coronavirus. American manufacturers needed to pivot production to ventilators, the breathing machines crucial to treating COVID-19. As of April 2020, many have stepped up: Dyson, Ford, Tesla, Maingear, and others. To date, thousands of machines have been built and delivered.
But: how? It takes companies with a mastery of supply and production, like Apple, at least a year to adjust from making, say, the iPhone X to the iPhone XS. How can the makers of vacuum cleaners, cars, and gaming computers suddenly start making medical breathing devices? And why is it easier for them to make new ventilators than for anyone to fix an existing machine?
For the last month we’ve been compiling repair and service information for ventilators (and other medical equipment). In that time, we’ve made some new friends in the medical field and learned a thing or two about these breathing machines. We want to share some of the things we’ve learned so far.
Let’s start from the top: a ventilator is a machine that assists or replaces the function of a human lung (more precisely, the diaphragm), bringing oxygen into the body and expelling carbon dioxide. Ventilators come in a variety of shapes and sizes, but are typically equipped with at least the following components, listed here with their functions:
- Patients who need a ventilator typically need oxygen in higher concentration than what’s available in the ambient air. To solve this problem, most ventilators take in pure oxygen from an attached tank, as well as the filtered ambient air.
- Combines oxygen and ambient air to a set ratio (we’ll call this mixture “air” from here on).
- Pressurizes and dispenses the appropriate volume of air, depending on the capacity and compliance (read: elasticity, stretchiness) of the patient’s lungs.
Note: Some ventilators, like the Siemens model diagrammed above, do not have distinct mixers or blowers, but mix and pressurize air throughout the system.
- Heats and humidifies mixed, pressurized air before delivery to the patient.
Tubes and masks
- Once the air is mixed, pressurized, and humidified, it leaves the ventilator through the inspiration tube (you’ll see why it’s called that in just a moment). This tube carries air to the patient’s lungs through an endotracheal tube or a respirator mask, depending on the condition of the patient and their capacity to breathe on their own.
- After the air passes through the lungs, it leaves through the adjacent expiration tube back to the ventilator, where its volume, pressure, and temperature are measured for display on a monitor, before it is filtered one last time and exhausted.
Sensors, filters, probes, and alarms
- A heck ton of them! We’ve mentioned a few already, but basically everywhere air moves inside a ventilator, it gets filtered. Almost every arm and leg of the machine has sensors that monitor pressure, air flow, temperature, and other critical stats to ensure the patient is always receiving the air they need, or alert someone if they are not.
Now that you know about ventilators, we can talk about the rapid spike in demand for them, and how the world is responding.
Split Up the Airflow
The first and most convenient response to a ventilator shortage is to multiply the productivity of existing ventilators. Hooking up multiple patients to one ventilator was investigated in 2006 as an emergency measure to “meet disaster surge.” That study was done with artificial lungs, but during the COVID-19 pandemic it was successfully performed with real patients.
There are several drawbacks, though. Chief among them that it’s an untested and unintended use of the machines. Additionally, the patients’ lungs need to have similar volume and elasticity for the technique to work, limiting its usefulness. At the end of March, several professional medical organizations including the American Association for Respiratory Care released a statement advising against sharing ventilators, stating that “it cannot be done safely with current equipment.” That’s partly why there’s a push for another solution.
Make New Kinds of Ventilators
Because clever reuse and adaptation only go so far, some new ventilators must be made.
Ford and GM were two of the first big firms to start manufacturing. Since then, other companies have assisted with ventilator design and manufacturing, all to prepare for worst-case scenarios.
What’s interesting is how these companies are stepping up so quickly. They are not manufacturing clones of existing medical ventilators. Instead, they repurpose components they already manufacture, and cobble them together into a working ventilator with all the parts we outlined above. Some of these pieces exist in similar form in cars (Tesla, Ford, GM) and fancy vacuum cleaners (Dyson). That’s why it’s easier for those companies to put together a working ventilator.
The FDA, not known for its responsiveness or agility, is stepping up in a big way by allowing these rapidly prototyped devices to go into production and into hospitals. Through an Emergency Use Authorization (EUA), ventilators made specifically to address the U.S. shortage can get approved and shipped more quickly. NASA, for example, made a ventilator that is smaller, more portable, and easier to maintain than traditional ventilators, and that is now approved. It’s also available under a free license.
This is not to say switching to ventilator production is just a corporate hackathon. Safety and reliability are paramount when designing and building a machine that will be responsible for keeping someone alive. Believe it or not (believe it), this ventilator explainer leaves out a number of ventilator technicalities.You need a computer, and specialty software, for example, to monitor and direct all of the components’ functionality, for example. And many hospitals have requirements for new machines beyond whether it works or not.
Dr. Matthew Aldrich, director of critical care at the University of California at San Francisco Medical Center, told the Washington Post that staffers at the hospital typically get a chance to discuss features on new ventilator models. “I would just hope that a similar process is being done to make sure we are investing our resources in a ventilator that can actually provide care that we need,” Aldrich told the Post.
Finally, however fast companies can turn out an entirely new product category, it may not be fast enough. The ventilators designed by Dyson, at a cost of $25 million, are likely not to be ordered by the UK government. It’s a generally good thing that the crisis may have passed in the UK. Yet Dyson may have put that money and effort into other means, had existing models been easier to get running again.
Best of All: Fix the Broken Ones
Even the newest ventilators will eventually need repair. Since the beginning of the COVID-19 outbreak, there have been headlines about broken ventilators. Some made their way here to California. Others are sitting in a federal stockpile. While big companies step up to fill the demand for new ventilators, traditional ventilator manufacturers sit quietly on the sidelines with tight fists and sealed lips, reluctant as ever to relinquish parts and repair information that will keep the ventilators they have running smoothly. This is why we’ve been compiling ventilator repair information here on iFixit.com, takedowns be damned.
Just recently, some manufacturers have come forward with ventilator and other equipment manuals. It’s not enough, though. As CEO Kyle Wiens noted, Medtronic released the manual only for a device they don’t sell in the U.S., not the flagship model used around the country. Similar gaps exist wherever companies volunteer to provide manuals only in response to criticism.
If there is one moment when holding back repair information looks foolish and harmful, when the Way It’s Always Been Done seems crazy, it’s this moment.
Top image by GM/Ventec.