kiwisue (kiwisue) wrote,
kiwisue
kiwisue

Global ProsWatch - Discovered in a Graveyard

After the big discussion about Doyle's recovery and rehabilitation on erushi's journal I went looking for more information about the wound itself and stumbled on
"The Writer's Medical and Forensic Lab, run by Doctor D P Lyle. It's a cool site with several articles and a Q&A forum (which seems to have only run for a year, but there are a decent number of questions there). Dr Lyle has also written a couple of books for writers.

There was already a question on the forum about a gunshot wound to the chest, but as the wound cited wasn't quite correct for Doyle, I decided to email Dr Lyle myself. I wasn't sure if I would get a response, so I was really impressed when, one day later, Dr Lyle sent a reply - and a second response to a follow-up question in equally snappy time.

*Warning - detailed description of injuries follows*


What I described was: The victim was shot twice. One bullet entered from the
> front, just below the heart, another from the back. The second bullet
> perforated the left atrium (not the aorta). From screen stills I've decided
> the gun is a relatively low powered Beretta M34. The first shot was fired
> across a room, say 3+ metres, the second closer to the prone victim, maybe
> 1.5-2 metres. According to the script the patient was rescued before bleeding
> out, went into fibrillation during surgery to remove the projectiles, but
> survived, and recovered in TV show time.




Dr Lyle's reply:
"The original question was a gunshot wound to the aorta in the chest,
which is known as the thoracic aorta. Once it drops below the diaphragm it
becomes the abdominal aorta. Either way surviving a gunshot wound to this
major artery is not likely but can happen. The wall is very thick and
muscular and when a bullet penetrates it, this muscular wall and spasm
(squeeze down or contract) and lessen the amount of blood loss. As blood was
lost and the blood pressure began to fall within this squeezing down would
become worse and there would be less pressure forcing the blood through the
opening and bleeding would slow even further to the point that it would
eventually stop in the wound would clot. Of course at this time the victim
would be in shock but he could still be saved. This spasm is a natural
reaction to injury in a virtually all the arteries of the body. I think
common sense would dictate that this was probably a life-saving evolutionary
adaptation since primitive man and animals lower down the family tree are
often injured in the real world and this would allow a mechanism by which
they could survive many of these injuries.

The atria of the heart however are a whole different story. The walls to
them are very thin, much thinner than the artery walls, particularly the
aorta. They do have a very thin muscular layer which is what allows the
atria to contract during the normal functioning of the heart, but the
muscular fibers are not arranged in a circular fashion around a tube as in
an artery, but rather are thin sheets of muscles. This means that the atrial
walls cannot contract around any defect that would occur such as in a gun
shot wound or a knife wound or any other penetrating injury. A gunshot wound
or any such injury to the atria are extremely deadly and in very short
order. Bleeding is severe and brisk and fills both the chest and the
pericardium, which is the sack at the heart sits in. It takes only a half a
cup or so of blood in the pericardium, which is not stretchable, to begin to
compress the heart. As the blood accumulates the heart is squeezed more and
more and will soon stop. This is called cardiac tamponade.

It would be better for your character to be shot in the aorta or even in
the heart muscle itself, which would be the ventricles, since these highly
muscular organs offer at least some chance of survival by the mechanism I
described above. An injury to the atrium would be almost universally fatal
unless it happened very close to a hospital and surgery could be done very
quickly.

This is dramatically demonstrated by gunshot wound to the abdomen. A
gunshot wound to the abdominal aorta is usually fatal but may not be because
of the spasm of the aortic musculature. On the other hand the vena cava,
which is the main vein that returns blood from the body to the right side of
the heart, is much thinner very similar to the atrium. Since there is no
spasm of the vena cava, it has no mechanism for preventing blood loss
through any defect. Whereas an aorta will spasm down and once the blood
pressure drops to 50 or 60 the bleeding will do dramatically reduced or even
stop, this is not the case with the vena cava where it will continue to
bleed until the blood pressure is essentially zero. This is exactly
analogous to the difference between a chest gunshot that strikes the aorta
and one that strikes the atria. Much better to be shot in an artery that a
vein.

So your victim would most likely die within minutes. However, if you
were saved and if the gunshot to the atria was the only major injury, and if
the surgery was done successfully, then he would recover after a couple
weeks in the hospital and a couple of months at home recuperating. He could
possibly return to complete activity since this type of surgery, if all went
well, is no more traumatic and would take no longer recovery time than would
standard open-heart surgery. This is all assuming that any shock or cardiac
arrest that he suffered during this entire ordeal did not do any significant
or permanent brain damage."

Answer to my FOLLOW-UP question about the surgery:

"If the bullet damaged the left atrium or the descending thoracic aorta, then the approach through a left lateral thoracotomy would be appropriate and would be the approach most surgeons would take. If the bullet damaged the right side of the heart then that is not the approach that would be taken. So it sounds like the episode got it right. In an emergency such as this, a median sternotomy approach—directly through the breast bone as in most open heart procedures— would be favored by many surgeons. But at the end of the day it’s a surgeon’s choice as to how he gets inside the chest."
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