A team of engineers found an innovative method to allow the sharing of ventilators among COVID-19 patients safely. This could be utilized as a last resort to assist patients during emergencies.
The innovative way to enable safer sharing of ventilators among COVID-19 patients was developed by engineers at the Massachusetts Institute of Technology (MIT), a private research university in the US. Their method involved the use of flow valves, one for each patient, to control the amount of air they would receive from the machine. While their method optimized the airflow, engineers cautioned its application as a final option if no other solutions were found. Their findings were published in the journal Science Translational Medicine.
Ventilators: What They Are and How They Work
According to a post on the media network The Conversation by Berto Pandolfo, a senior lecturer in product design at the University of Technology Sydney, ventilators are machines designed to assist the breathing capability of a sick person suffering from respiratory impairment. Ventilators augment the inhalation and exhalation of air. Through oxygenation, the machines pump or blow oxygen-rich air into the patient's lungs, while in ventilation, the machines remove carbon dioxide from the organs. In a way, the machines mitigate some stress in the lungs.
In the COVID-19 pandemic, ventilators are critical in patients with severe symptoms. Since their lungs are under intense stress, they need assistance to breathe as normal as possible. But there has been a shortage in the supply of ventilators worldwide. As such, some hospitals have no choice but to use one ventilator for two patients to accommodate more individuals. When the creative move reached medical organizations, a warning was issued among practitioners due to the dangers of sharing one ventilator.
A joint statement from various major organizations was posted by the American Society of Anesthesiologists, a scientific association dedicated to anesthesiology and patient care, to forbid affiliated clinicians from allowing ventilator sharing. The statement revealed that current ventilator designs were not optimized to serve more than one patient. On its own, a ventilator could face challenges in normal circumstances associated with a mortality rate of between 40% and 60%, in patients with acute respiratory distress syndrome (ARDS) and non-homogenous lung disease, meaning the complexity of COVID-19 could worsen that mortality rate.
Among various reasons why a ventilator should never be shared were ethical issues. In the event that the machine could save a life, its use for two patients might risk both lives, especially if their illness was life-threatening. So far, COVID-19 could be considered as a life-threatening infection. On top of that, if one of the patients sharing the machine goes into cardiac arrest, the machine would have to be stopped to change the bag ventilation. Doing so would prevent the virus from aerosolizing and infecting healthcare workers, but it would risk the life of the other patient.
Engineers Propose Technique to Optimize Ventilator Sharing
At MIT and Brigham and Women's Hospital, engineers suggested an innovative method to enable safe ventilator sharing between COVID-19 patients. They added certain components to the existing sharing method. The components would optimize the flow of air delivered into the patients' lungs. The optimization could result in personalized airflow to meet the need of each patient. Also, the method could warn healthcare workers if something goes wrong.
"We hope this approach, which requires off-the-shelf components, can ultimately help patients in extreme need of ventilator support. We recognize that ventilator sharing is not the standard of care, and interventions like this one would only be recommended as a last recourse," said Giovanni Traverso, an author of the study and assistant professor of mechanical engineering at MIT.
Engineers explained that the ventilator sharing approach was demonstrated back in March via a T-shape connector. The connector creates two branches that lead to each breathing tube of two patients. Although it looked simple, doctors had to closely match the age, size, and condition of patients to ensure they would receive the same volume of air. The risk could arise from the condition of each patient connected.
When the condition of a connected patient improves, their lungs can absorb more air and it affects the air volume delivered to the other patient. On the other hand, if the condition of a connected patient declines, their lung may collapse and a burst of air can be directed to the other patient, which may damage their lung. The decline scenario can endanger both connected patients.
To resolve that risk, engineers applied flow valves and integrated them into the connector. The valves could help personalize the amount of air each connected patient should receive. If a patient either improved or declined, the valves could be adjusted to prevent problems from occurring with the other patient. They also integrated pressure release valves to avoid excess air going into the patient's lungs and alarms to notify attending medical staff if the air intake of a connected patient suddenly changes.
The method utilized parts typically available in hospitals. If none could be found, the parts could be obtained at hardware stores and then sterilized before installation. A standard ventilator could provide sufficient air pressure for up to eight patients at a time. Though, engineers warned not to apply the method on more than two patients. If more are connected to one ventilator, the setup would be more complicated.
Ventilators are often used on COVID-19 patients with severe symptoms or in a critical state. This means that every patient will require a machine to help them breathe. According to Statista, a German portal for statistics, as of February 11, 2020, the majority of cases in Mainland China were mild. Out of 44,672 cases, 80.9% were mild, 13.8% were severe, and 4.7% were critical. Still, the number of severe and critical cases in the country impacted the supply of ventilators.
Meanwhile, in Italy, as of May 20, 2020, the total cases reported were 227,364 across cities. Out of that, 62,752 were active cases, 132,282 were cases of recovery, and 32,330 were confirmed deaths. Despite the number of deaths, the collective effort from the government, the healthcare sector, and the public resulted in about 58.1% of recoveries from all cases.
The engineers are now working with third parties to seek emergency use authorization for their method from the US Food and Drug Administration. The authorization will allow its deployment in the clinical setting if no other options can be applied by healthcare workers.