How to Share a Ventilator across Multiple Patients with Patient Independent Ventilation Settings, Monitoring, and No Cross-Contamination

Around the same time, Dr. Lorenzo Paladino et al. devised a similar experiment to answer the same question. Instead of using a ventilator to ventilate four lung-simulator devices, they tried out the technique on four human-sized sheep. 

They treated the sheep as if they were human patients with lung impairments and breathing problems. The “patients” were sedated, intubated, and hooked up to a ventilator that did the breathing for them.

In short, it worked. The ventilators kept all four “patients” alive for 12 hours. Sedation was turned off and all four patients started to breathe normally again on their own.

This is the paper Dr. Paladino and his colleagues wrote describing their findings: Increasing Ventilator Surge Capacity in Disasters.

For many years, nobody had attempted (or at least hadn’t documented their attempts) to use this approach on human patients. 

However, that changed on October 1, 2017. On that day, Dr. Kevin Menes was running the Emergency Department at Sunrise Hospital near Las Vegas, Nevada. In the middle of his shift, the deadliest mass-casualty gun shooting in modern American history took place. In the hours that followed, Dr. Menes and his team (and auxiliary staff) would end up treating over 215 penetrating gunshot wounds… in seven hours. (If this isn’t the definition of a hospital overwhelmed, I don’t know what is.)

As you might imagine, major blood loss impaired many patients’ abilities to breathe and get enough oxygen circulating with whatever amount of blood remained in their bodies.

As the surge of patients flooded the Emergency Room, the hospital had run out of ventilator machines. (Sound familiar?)

In his own words, here’s what Dr. Menes did…

“…the respiratory therapist, said, ‘Menes, we don’t have any more ventilators.’ I said, ‘It’s fine,’ and requested some Y tubing. Dr. Greg Neyman, a resident a year ahead of me in residency, had done a study on the use of ventilators in a mass-casualty situation. What he came up with was that if you have two people who are roughly the same size and tidal volume, you can just double the tidal volume and stick them on Y tubing on one ventilator.”

You see, Dr. Menes had trained in the same hospital as Dr. Neyman and was familiar with his experiment using a splitter on a ventilator. 

You can read Dr. Menes’ personal account of that night here: How One Las Vegas ED Saved Hundreds of Lives After the Worst Mass Shooting in U.S. History.

Now, there are several issues with using splitters with ventilator machines.

1. Using a splitter is a non-standard, “off-label” use of the device. It’s not a normal standard of care. Hence, all the studies have suggested such a configuration would only be used in a mass-casualty situation (which is defined as when you have more patients than you can handle). If we’re not at a mass-casualty situation yet, we are certainly on our way there — especially in certain regional COVID-19 hot spots in the United States.

Dr. Babcock proposes the following approach to navigating this issue. To paraphrase, if I have one ventilator and four patients, here’s what I would say to the four families, “Your loved one needs this machine or he/she will likely die. I can pick who gets it, allowing three of your loved ones to die, or you can share the machine. What do you want to do?” 

(I suspect that, when faced with the choice of a 75% chance of certain death versus sharing a ventilator, most people would be fine with sharing.)

2. Sharing a single ventilator does create a risk for cross-contamination. You would not want to share a single ventilator between three COVID-19 patients and one non-COVID-19 patient. Such usage would very likely cause the non-COVID-19 patient to be infected. However, if all four patents are already infected, then this risk is mitigated.

3. Grouping patients requires similar tidal volume needs. All two or four patients sharing the ventilator must have similar ventilation needs. When one ventilator is assigned to one patient, the ventilator settings can be adjusted to meet the single patient’s needs very precisely. When two or four patients share a ventilator, you use a single setting for all patients. This means you want patients of a similar body weight (as this determines the volume of air they need per breath). You also want patients with similar degrees of lung impairment as the breathing capacity can vary significantly based on this trait.

4. Patients need to be placed in close proximity to the ventilator, but ICU rooms aren’t designed for that. I’ve only been to the intensive care wards at two hospitals — one community hospital and one research hospital (UC San Francisco). These wards are designed to prevent infection between patients. As a result, each patient has their own room or at least their own alcove (a room with three walls, with the fourth wall “open” and visible to the nurse’s monitoring station).

In other words, you can solve the ventilation problem, but now you have a “real estate” configuration problem to solve.

Let me discuss this fourth issue in more detail. One of the principles of scaling up operations to meet surges in demand is to remove the point of greatest constraint in your system. In the case of COVID-19, ventilation capacity is one of the top constraints. Using the splitter solution, ventilation patient capacity can be increased between two to four times without any change in the number of ventilation units. 

However, every time you fix the greatest constraint, you will suddenly discover the second greatest constraint. In the case of scaling patient ventilation capacity, the new constraint becomes “real estate,” or floor space. 

Standard intensive care unit configurations (at least the ones I’ve been to) aren’t set up to group two to four really sick patients together. The premise has always been to separate them. While solving one problem (patient ventilation capacity), you create another problem (suboptimal floor space configuration). 

However, you’re ahead of the game if you trade-in a major headache for a lesser headache.

In this case, the number of ventilators in the country is more or less fixed in the short-term. However, we have more “real estate” available to us than ventilators. So all else being equal, I’d rather have a solvable “real estate” problem than a ventilator shortage problem. That said, someone still has to go figure out how to solve the “real estate” problem.

5. Legal Liability — It would be extremely helpful if this approach could be validated further in the field and receive an expedited approval, or at least some kind of crisis waiver from the FDA, to use ventilators in this particular way. Until then, it would make sense for hospital general counsels to start drafting “Consent to Treat” forms for this non-standard ventilation usage — just in case things get so bad that doctors and nurses need to use it. This kind of scenario is entirely anticipatable and, when running fast-moving operations of any kind, you want to solve the anticipatable problems early so that your top talent only has to deal with the unanticipated problems. 

6. Developing a Three-Way Splitter — All the academic studies and field experiences have either split the air from a ventilator to two or four patients. This is because standard equipment available in an emergency room allows for these configurations. However, since a single full-featured ventilator can ventilate patients with a combined weight of 627 lbs, we could get more efficient capacity utilization with a three-way splitter. For example, a three-way splitter could allocate 627 lbs worth of patient ventilation capacity to three patients weighing approximately 209 lbs or less. The average adult male is 200 lbs. This would serve even more patients than ventilators that only use a two-way or four-way splitter.

7. Scalable Knowledge Transfer — Someone from the National Institutes of Health, Centers for Disease Control and Prevention, Department of Health and Human Services, and state-level health boards should each be contacting Drs. Neyman, Babcock, Paladino, and/or Menes to more precisely document their collective knowledge, write down what they recommend regarding this protocol in specific detail, and disseminate such knowledge to all the hospitals in the country. 

Hopefully, things don’t get so bad that we need to do this. But, hope is not a plan. We should prepare by forwarding knowledge of these techniques to those who need to know. This is an essential part of increasing critical-care capacity (a.k.a. “raising the ceiling”) in our country. 

COVID-19 moves fast. We need to move faster. While publishing in peer-reviewed journals is the gold standard for introducing protocol innovation in the healthcare field, we do not have the time. In a crisis, perfection is the enemy of good enough. 

My goal in writing this article is to bring attention to the findings of Drs. Neyman, Babcock, and Paladino that have since been proven in the field by Dr. Menes. My hope is that others can build on and improve upon their work and have back-up options if we do run out of ventilators. I would appreciate it if you would pass along this message to as many people as possible — especially those who are experts in the medical, intensive care, emergency care, or government health industries.

Update 3/18/2020 9:20 am PT

8. Optimal for One vs. Suboptimal for All — One issue is that a ventilator’s settings are usually tailored to a specific patient’s vital signs. What happens if one patient needs a higher setting that would cause another patient to receive “too much”? In particular, there’s a concern around PEEP (positive end-expiratory pressure). This is the amount of air pressure the ventilator produces at the end of an exhale to prevent the alveoli (oxygen exchange area of the lungs) from “collapsing.” As I understand, this pressure setting varies from patient to patient and isn’t correlated with body weight but more so patient illness status.

The consensus feedback is that this approach clearly isn’t ideal (which is why it is not standard practice). There are no studies on long-term outcomes. However, if desperate enough, such configuration could work as i) a temporary solution until each patient gets their own ventilator, or ii) becomes a difficult triage decision: Is it better to treat four patients suboptimally or one patient optimally?

Examples and Field Reports

• March 17, 2020: Rural physician Alan Drummond is doing this in Ontario, Canada.

• Peter Attia MD reports an ICU at a hospital in New York has also started “double venting,” putting two patients on a single ventilator.