Without More Ventilators, Would It Be Possible for Two Patients to Share?

Respirators

Is this the way to save more lives? A respiratory expert weighs in on this experimental idea…

To say Professor Richard Branson is an expert on ventilators would be an understatement. Not only is he a respiratory therapist — but Branson is also a professor of surgery at the University of Cincinnati and the editor in chief of the journal Respiratory Care. He has worked closely with the Strategic National Stockpile and the CDC, advising them about ventilator stockpiles. So he’s perhaps the best person to turn to for any pressing questions about ventilators… and right now, many of us have a ton.

Luckily, our Wake-Up Call newsletter could turn to Professor Branson for some answers. Here, he explains to our producer Emily Pinto how exactly a ventilator works, why they’re so vital in the response to Covid-19, and why sharing these devices is more complicated than you’d think.

Wake-Up Call: Ventilators and respiratory health are making daily headlines amid the coronavirus pandemic. So, first things first: What does a respiratory care specialist’s job usually entail — and how has this crisis changed that?

Prof. Richard Branson: The average respiratory therapist usually works in the ICU, and is responsible for monitoring between four and six patients on ventilators each day. They may also monitor a couple of other patients who aren’t on a ventilator but might be on a breathing treatment to improve their lung function. In a medical ICU, these are mostly patients with emphysema or chronic obstructive pulmonary disease, or they’re patients with what we call “community-acquired pneumonia,” which means they acquired it out in the world, not while they were in the hospital. Surgical patients who are on ventilators are usually trauma cases: gunshot wounds, knife wounds, automobile accidents, or major surgeries for things like cancer or vascular disease.

These therapists monitor patients for the number of breaths per minute, the size of the breaths, and how much oxygen and pressure they should be getting. But more importantly, they’re monitoring patients’ response to the treatment. Does their blood have adequate oxygen? Are they eliminating carbon dioxide? Is their airway clear? All of those things are part of a respiratory therapist’s normal day.

During this pandemic, in New York, for example, there might be 100 patients on ventilators in a hospital, with eight or nine respiratory therapists taking care of them. So there’s an increase in both the number of patients and the severity of their illness. On a normal day, a respiratory therapist may be monitoring one or two people who are really sick, and others who are getting better. But many Covid-19 patients need constant monitoring, and there are fewer staff members to monitor them because the staff is getting sick.

Now, can you explain to us how ventilators work — and whether we can share them?

A ventilator delivers gas to a patient and adjusts for the size and pressure of the breath, the timing of each breath, and whether the patient is responding appropriately. Those settings are specific to the patient and their needs and will be adjusted as the patient gets better or worse. When you add a second patient to one ventilator, now both patients have to get the same amount of oxygen and the same amount of pressure, and you can’t separately monitor what each patient is getting.

So hypothetically, if the patients have very similar lung compliance — which is the stiffness of the lung, or how much pressure it takes to push the desired volume of oxygen in — you have a modicum of potential for success. But mechanical ventilation is complicated. Even if two patients have the exact same lung compliance when you start them on a ventilator, it doesn’t mean it’s going to stay that way.

Can you break this down a bit further for us?

Imagine two balloons are connected to one ventilator, and each balloon represents one patient’s lungs. On day one, maybe both of those balloons look and feel exactly the same. But on the second day, patient A starts to get sicker — as though someone put a rubber band around their balloon. So now when you deliver the gas from the ventilator, patient A’s balloon is really restricted. It can’t blow up as much.

So patient A now isn’t getting enough air, and patient B is getting too much air. It’s a distribution problem. The worst possible situation is that one patient gets better while the other gets worse. So the patient who is getting better is getting too big a breath, which can injure the lungs. And the patient who is getting sicker gets a smaller breath, so isn’t getting enough oxygen in or carbon dioxide out.

It’s almost as if I took two different people’s temperatures and I averaged them and treated them based on that average. The average doesn’t really tell me anything about how either person is doing individually. When you have two people on a ventilator, you only get one number with the settings of what’s going into the patients and one number of what’s coming back out, but you don’t know who got what share of it. That’s a big danger.

Then, what happens if one patient on a shared ventilator has a catastrophic event? If one patient’s lung ruptures, air escapes out of the lung and gets trapped in the chest and pins the lung down. That’s called a pneumothorax. That’s a life-threatening situation for one patient on one ventilator. If one patient gets a pneumothorax in tandem with another, now it becomes an emergency for both patients.

What happens in a scenario when a hospital has run out of ventilators, and doctors feel they have no other option but to put two patients on one ventilator?

In that case, you have to try to make it as safe as humanly possible as a really short term solution. But then the issue of ethics comes up.

Now let me be clear: I’m not an ethicist. Dr. Lorenzo Palladino of SUNY Downstate Health Sciences University in Brooklyn has said, “This is for the doomsday scenario when we run out of ventilators… it’s suboptimal, but the other option is death.” And that’s probably true.

But hypothetically, what if patient 1 is already on the ventilator — and remember, the mortality rate from this disease is really high, so if you need a ventilator, your chances of survival, based on age and underlying conditions, are not good. But let’s say patient 1 is on the ventilator and has a mortality rate of 40%, based on the fact that maybe he or she was young and healthy before getting Covid-19. But then patient 2 comes in and needs to be put on the ventilator, or they are going to have a mortality rate of 100%. So maybe I put both of them on the same ventilator. Now I have significantly increased the chances that patient number 2 is going to survive, but I may have decreased the possibility that patient number 1 is going to survive because I couldn’t optimize the ventilator for either of them.

This is all theoretical of course. It’s been tried on test lungs, and sheep, but nobody’s tested this in a real-life scenario. I would never criticize the incredibly difficult choices some doctors who are in this mess may have to make. They are up against the wall, and have to make decisions to try to help as many people as they can. But it does bother me when I see videos on YouTube that make sharing a ventilator look simple — that couldn’t be further from the truth. It required careful, ethical application of this technique by physicians who know how high the risks are, but decide it’s their best option in an otherwise hopeless situation.

I think it’s also vital that families are made aware in these situations. These are your options: You can either not have your loved one put on the ventilator, or we can try to share the ventilator with another patient, but here are the risks. Let the families make those decisions. There have to be very open conversations where both staff and families know all of the risks. And if we reach that point where there are no other options, we’ll have to see what the data says. These hypotheticals are why flattening the curve is of critical importance.


This interview has been edited and condensed.

This originally appeared on Medium.com