COVID19: Ventilators

As of early April 2020, the news discussion about COVID-19 has become more focused specifically on the the availability of ventilators.

Clearly many patients have conditions that escalate to the point of being in danger of immediate death if they do not get a ventilator.

Ventilators are expensive equipment and their operation involves invasive procedures that require close medical monitoring, thus consuming limited supplies of both equipment and medically trained personnel.

One of the fears that will likely become a reality is that medical people will need to make choices as to who will not get a ventilator to make it available for someone else.   In particular, the optimal choice for saving lives may be to take a ventilator away from a patient near death but not yet dead in order to give it to a newer patient where there is more chance to save the life.

It is clear that patients are reaching the point where their continued life support requires a ventilator.   Some people getting ventilators do eventually recover.

If there were an infinite supply of ventilators that required very little medical supervision, then the right strategy is to give ventilators to everyone who needs it to continue to survive.    Some proportion of those patients will survive.

As we approach scarcity of ventilators, we need to know the effectiveness of ventilators.

Many if not most people who die in hospital from this disease dies while using a ventilator.    The ventilator did not save their lives.

Meanwhile many people admitted to hospitals due to complications from this disease end up recovering without needing to use a ventilator.    Even more people with this disease do not require hospitalization.

Based on superficial news about the ventilator shortage makes it sound like ventilators assure survival of the patients.   The primary benefit of a bountiful ventilators may be to save the sanity of the health workers by protecting them from the choice of having to remove a ventilator from one patient to make it available to another with better prospects.  Even if the first patient has nearly no prospect of recovering, removing life support before natural death is something no one wants to happen in our hospitals.

There are two patients.  One option is the attempt to save a person who might survive with the help of a ventilator by taking it away from a patient already using a ventilator but is unlikely to survive.   The other option is to wait for the natural death of the current ventilator user even if that means accepting the death of the newer patient.

The ventilator itself is not a treatment for the condition and certainly not of the disease.   The following quote describes the situation well:

In general, the chances of survival after being put on a ventilator are excellent if you are buying time for a therapeutic intervention to work. In general, survival chances are still very good if you are using the ventilator to help the lungs while the patient’s body is regaining strength, healing up. Like, say, after multiple rib fractures, or a gunshot wound to the chest after the damaged parts have been repaired or removed and bleeding stopped. In general, the survival chances are not so good for patients who are old and frail, perhaps chronically ill with no reserves, if we don’t have good therapeutic interventions for the specific cause of their decline.

While there are preventive measures that may help prevent COVID-19 virus infection, there are not many options available to treat the disease especially after it progresses past the point of needing a ventilator.   As a result, I don’t think COVID-19 meets the pre-requisite for using ventilators in the first place.   We don’t have good therapeutic interventions for this disease (outside of experimental gambles).

I have been hearing various reports that between 30% to 50% of patients getting ventilators will not recover.   Even in good unstressed hospital environments (see article for context):

“Four in 10 might not make it,” said Fowler, based on early North American data of COVID-19 patients who have required ventilators. Survivors are often younger, without underlying health conditions.

I think that number may be optimistic in coming weeks when the hospital resources and staff become over utilized.

The same article states that the use of ventilators can cause more damage

Spending several days or longer on 100 per cent oxygen can damage the lungs, Kumar said.

With high pressure from the ventilator, unhealthy lungs tend to become stiffer, so it takes more pressure to expand them, which can also cause lung injury.

and pose heightened risks to health providers (as well as consuming limited supplies of personal protective equipment):

Also, when health-care workers intubate a patient, they’re very close to the mouth of a person excreting large amounts of virus, which is dangerous for them, he said.

“It’s very easy to acquire infection unless you take appropriate and very stringent precautions.”

Survival rates from use of ventilators is not very promising for this disease.   I suspect it may have some value for treatment already started days before where the ventilator is needed for just a day or so to allow the treatment to turn around the patient.

I don’t know the prospects of survival for each additional day that a patient is on the respirator.   I suspect that being on a ventilator much more than a day reduces the patient’s chances of survival probably to near zero.   To make the ventilator available for a patient with better prospects, the medical staff needs to hasten the near-inevitable death of a current ventilator user.

The recent controversies and panic about the inadequate supply of ventilators (such as here) suggests that ventilators offer more value than they actually do.

We may be better off not using the ventilators at all for treating complications of this disease.   Given the low survival prospects of those getting ventilators, not using ventilators at all may not change the death rate much. Countering the modest number of patients saved by ventilators are:

  1. the exhaustion of hospital staff needed to administer these devices, diverting their efforts away from where they could be of more help with patients at earlier stages of the disease
  2. attrition of hospital staff ending up getting infected as result of the heightened risks from administering the ventilators
  3. The loss of life for unavailability of ventilators for other conditions where good treatment plans exist making the prospects for recovery much greater.

We may be wasting valuable energy and attention on obtaining, allocating, and stockpiling ventilators that are not going to change the overall statistical outcomes of this pandemic.   We may be better off focusing our attention on other more productive avenues for protecting the population from reaching the point where ventilators are the last available option.

The best policy for overall managing the COVID-19 pandemic may be to remove ventilators as part of the treatment plan.  Clearly ventilators are not going to be of any help when we run out of them.    Ventilators may have been of some benefit very early one when there were very few patients.   That time may now be in the past.  Give up on ventilators, and put our attention and resources elsewhere.

One thought on “COVID19: Ventilators

  1. Pingback: Render to COVID19 what is COVID19’s | Hypothesis Discovery

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