medium | What to Wear, What to Wear …
“Do you want PAPRs?” asked the resource nurse.
These
are Powered Air-Purifying Respirators: In our case, a white plastic
hood with a clear face shield, attached by hose to a motorized
fan/filter worn on a belt around the waist. We don these spaceman hoods
now for high-risk situations like intubations, the prologue to putting a
patient on a vent.
If
a patient is failing despite oxygen, then he might need sedated,
intubated (i.e., have a plastic breathing tube slipped into his
trachea), and put on a ventilator. We do this routinely in emergency
medicine. But it involves getting up close with a coughing, struggling
airway — perhaps between periods of vigorous bag-mask ventilation — and
it turns out this is all high-risk for aerosolizing a coronavirus, so
that it floats in the air all around us.
This
happens in a negative-pressure room — resource was already tracking the
patient in the computer to our main resuscitation bay, which has a
sliding glass door and a fan that continuously sucks air in from the
hall — so no viral particles can wander the ER. The fans draw the air
through filters and outside of the building — hopefully someplace up
high and remote, where any few scattered viral or bacterial particles
that make it so far will be killed off by sunlight. None of this,
however, protects those of us inside the room, hence the question: Should we dress like astronauts to meet the new COVID-19 patient? Or go with standard gear?
Standard
included an N 95 mask, which each of us had been wearing all shift, for
weeks now. They feel like hard cardboard, with moldable edges. When
sealed to the face, supposedly they keep out “95%” of whatever’s
floating in the air — as long as that whatever is bigger than 0.3 micrometers (300 nanometers). (This is regulated by the National Institute for Occupational Safety and Health; the N stands for “not resistant to oil,” which means it’s fine for healthcare work but not for some industrial processes.)
If
you’re wondering: “Is filtering out 95% enough?” — join the club.
Sucking in 5% of the coronavirus that comes my way sounds like a bad
deal.
Worse, the coronavirus itself is only 0.125 micrometers (125 nanometers). So … small enough to make it thru the mask?
Nevertheless, we have some clinical evidence that N 95s prevent viral or bacterial infections. And we hypothesize
that if say a coronavirus is floating in the air, it’s doing so in a
large water droplet. Suddenly, the exact size in micrometers of said
droplet is of interest, so there’s a brisk trade in math-heavy papers like this one from the Journal of Fluid Mechanics
— with its 1,000-frames-per-second images of sneeze- and cough-expelled
saliva sprays. This and other literature suggests virus-filled saliva
droplets range from 5 to 15 micrometers (5,000 to 15,000 nanometers)—
far too big to make it past the N 95.
Maybe so, but the N 95s are miserable things.
Before COVID-19 they were considered “single-use,” worn to see a patient and then discarded upon leaving the room.
Now,
in the setting of an international shortage, at every hospital I work
at or know of, they are being used in a completely new way: Worn constantly,
sometimes with a surgical mask over top to “keep the N 95 clean,” and
then turned in for some sort of deep cleaning. The CDC has offered only the most grudging of guidance
blessing this sort of reuse, but what can we do? At least we are past
the early days, when we doctors were literally studying the specs on
vacuum cleaner bags and air conditioner filters, wondering if we could
cut them up and sew them into face masks.
To
be clear: At none of the hospitals where I work did we ever run out of
protective gear. But at all of them we had reason to worry about it, and
if we haven’t run out, it’s in large part because of the ingenuity of
the physicians and nurses in suggesting workarounds.
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