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all right now we're going to move on to
some other pulmonary life threats the
next one is open pneumothorax so open
pneumothorax is kind of interesting
physiologically this happens when you
have a large open defect in the chest
wall and if we all remember our fluid
flow physics when you have a a tube and
you're trying to determine the rate of
flow through that tube the primary
determinant of flow is going to be the
radius of the tube and then the second
most important determinant is the length
so if you think about your trachea as a
tube and you think about the hole in
your chest wall as a tube you can
imagine the chest wall is a much shorter
tube right it's a lot smaller than the
trachea so when that wound goes up to
two-thirds of the tracheal diameter it
doesn't have to be the size of the
trachea or bigger than the trachea it
can still be smaller because the tube is
so much shorter when that happens
inspiration is going to preferentially
pull air through the wound into the
pleural space rather than going down the
trachea and into the lungs so if you
have a large enough defect here you're
not going to pull air through the
bronchial tree the way you're supposed
to you're gonna pull air in directly
through the wound when you breathe now
as you can imagine if you're just
sucking air into your pleural space
through a hole in your chest that's
going to render your ventilation pretty
ineffective so this can result in lethal
hypoxia and respiratory failure if it's
not treated promptly so again large
wound in the chest wall on physical exam
anything bigger than two-thirds the size
of the trachea is gonna cause air to
preferentially flow into the wound this
is also known as a sucking chest wound
and that's because these wounds make a
delightful sucking sound during the
respiratory cycle you can actually hear
air being pulled in through the wound
and it goes with every respiratory
effort it's going to cause hypoxia and
respiratory distress and you don't need
radiologic confirmation for this you can
actually
see the wound you can hear the sucking
sound you can appreciate the patient's
respiratory distress you're going to go
ahead and treat it so the treatment is
very satisfying ly simple you basically
just place an occlusive dressing over
the wound and what's going to happen
when you do that is when the patient
breathes in now you've got the whole
occluded so it's going to suck the
dressing up against the chest wall but
it's not going to let any air go through
the wound
well if air can't get through the wound
where it's where's it going to go now
it's going to go down through the
trachea into the bronchial tree where it
belongs however we want to make sure
that we allow air to escape from this
wound during exhalation because you
don't know what kind of injury there is
to the underlying lung and you don't
want to create a tension pneumothorax so
the way we do this is by securing the
occlusive dressing only on three sides
and that creates a one-way valve effect
so when the patient breathes in no air
goes through the wound but when they
breathe out air can escape out through
the wound if it needs to and that's
going to prevent the development of
attention in the thorax these patients
always need chest tubes for definitive
management again the lungs not going to
be able to re-expand and heal unless you
restore the negative inner thoracic
pressure which is accomplished with a
chest tube and there is a high incidence
of underlying injury you can imagine
that any kind of traumatic mechanism
that makes a big hole in your chest wall
is going to be very likely to be
associated with other pathology so these
patients often end up going to the
operating room for other reasons all
right next pulmonary life threat to talk
about is flail chest flail chest occurs
when you have multiple rib fractures so
basically if you have multiple fractures
of ribs that are adjacent to one another
and the fractures are present in two
different locations you get a section of
rib that is discontinuous from the rest
of the thoracic cage well what's going
to happen to that section of rib it's
not tethered down to the other ribs now
so it's not going to move normally
during the respiratory cycle it's going
to actually move paradoxically
so normally when you breathe in your
ribs follow that bucket handle motion
and sort of expand but now you've got a
section of chest wall that's not going
to do that it's going to go and suck up
against the lung during inspiration this
is going to directly impair ventilation
right because yet now you have a section
of rib that's floating around doing its
own thing and it's gonna also be
strongly associated with underlying
pulmonary contusion because this section
of rib one it got broken somehow so
clearly there's going to be a high
likelihood of transmission of energy to
the underlying lung and two you are
repeatedly injuring the lung by pulling
this section of rib up against it over
and over again so patients with flail
chest you're going to be able to
physically see a chest wall deformity on
your clinical exam this is not going to
be a subtle finding you're going to see
that paradoxical chest wall movement in
the area of affected rib you're going to
see infiltrates on your chest x-ray
which are suggestive of underlying
pulmonary contusion and the treatment
for this in the EEG is really going to
be supportive we're going to want to
make sure that we provide the patient
with supplemental oxygen that we
maintain their oxygenation that we
intubate and mechanically ventilate them
if they are in significant respiratory
distress but there's not really any
definitive treatment that we can offer
for this in the edie setting in many
cases these patients with supportive
care will just go on to heal their rib
fractures and be fine although there are
situations where surgical fixation of
the chest wall might be necessary
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