PULMONOLOGY • CONTINUED FROM PREVIOUS PAGE
Precision
electronics
you can
bleach
To some degree, almost everything conducts
electricity. There’s a tiny amount of current passing
between you and the cell phone in your pocket right
now, for example. Not that you’d ever notice.
But when you’re working with imperceptible
amounts of current like those used in EIT, you notice.
“The hardest, biggest challenge of bringing EIT
to clinic is that you have interference from other
electronics in the room,” says Dr. Mellenthin.
Even in a lab setting, measurements of perfusion
are just barely above the level of noise. In a hospital,
where any number of instruments and monitors
might exchange current with the leads strapped to
a patient, isolating those measurements is difficult,
to say the least.
There are elements of circuit design Dr. Mellenthin
can arrange to filter out some of that noise. It’s an
iterative process. The downside, though, is that the
filters inevitably compromise sensitivity.
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“You have these conversations over and over again,”
she says. “What can we get away with in terms
of noise that makes images good and the device
functional? Mathematicians want to prioritize data
quality at all costs. On the other side, you have
clinicians who actually need to use the device.”
And electrical noise is far from the only problem
the clinic presents. Electrodes don’t like to stick
to a sweaty patient. Salt content can throw off the
readings. The machine that works has to strike a
delicate balance: precise enough to be accurate,
robust enough for the unforeseen.
Oh, and you have to be able to clean it with bleach.
“One surgeon I brought it to, the first thing she said
was, ‘Okay, what if a patient throws up on it?” Dr.
Mellenthin laughs. “They don’t teach you that in
engineering school.”
SURGERY
Fetalizing the Adult
Totally sheltered, totally
dependent, fetuses inhabit an
environment entirely apart from
that of any other stage of life.
They have, as a result, unique
properties. One fetal surgeon and
his research team are applying
those properties to diabetic
wounds — but the implications of
their work go far deeper than skin.
It’s a fact known to fetal surgeons like Kenneth
Liechty, MD, that fetuses can heal perfectly,
without scars. Surgeries, heart attacks, tears and
contusions to organs, tendons, skin — fetuses
weather them all and come out like new. Fetal surgeon
“You look at animals like the salamander that can
regrow limbs or the zebrafish that can regenerate
tissue,” he notes, “and really the only real
mammalian example of that is the fetus.” adults. The results
Kenneth Liechty, MD,
applied properties
of fetal healing to
diabetic wounds in
were astonishing.
That’s always fascinated Dr. Liechty. Early in his
career, he and colleagues observed that preterm
infants were more susceptible than full-term
neonates to overwhelming sepsis, suggesting a
NEW CONSTELLATIONS
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