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PeteMC
06-25-2016, 08:23 PM
Hope someone can help me with this - I'm writing a secondary world fantasy with roughly 15th century level medicine.

I've got a minor character, a fairly fit and healthy soldier, who took a nasty shrapnel wound in the upper thigh, close to but not actually hitting the femoral artery. He didn't get medical attention for a while, and lost a lot of blood (exactly how long and how much is adjustable).

Medical care is rudimentary - the physician has cut the shrapnel out of his leg, cleaned, stitched and dressed the wound. They're indoors in a relatively (for the setting) clean environment, and the physician has stayed with him so he's getting clean dressings as required.

Now I'd like this guy to survive if I can make it look plausible, although it's not the end of the world if he doesn't. As it is I've got him in a coma from the blood loss, with the physician giving him as much water as he can get him to swallow. So, three questions:

1) Is the coma realistic? If not, how would his body react?
2) Is this survivable, assuming the wound doesn't go bad?
3) If the above two questions can be answered "yes", how long is it likely to be until he wakes up?

Answers and pointers to anything else I've missed/not thought of/got plain wrong would be much appreciated, many thanks.

Perks
06-25-2016, 09:07 PM
I have a friend who lost more than half her blood, and refused a transfusion. Her full recovery took better than six months. It's my understanding that coma would not be a primary concern, unless of course there is brain damage from oxygen deprivation. Then that's a whole 'nother world of problem. Organ damage is of primary concern, and if that doesn't happen, what you're really left with is profound fatigue in functional anemia and chronic low blood-pressure. You simply don't have enough blood for a while to get all the oxygen and nutrients around to keep you lively. Fluid volume is tricky, because electrolytes can become imbalanced and cause a host of problems.

The immediate problem is hypovolemic shock (https://www.nlm.nih.gov/medlineplus/ency/article/000167.htm).

Here's some basic info on coma (http://www.webmd.com/brain/coma-types-causes-treatments-prognosis), if your need to tweak your scenario to get your guy in a coma.

PeteMC
06-25-2016, 09:23 PM
That's really helpful, thanks. The coma isn't important, that was just my first guess at what would happen so I can easily take that out again. Hypovolemic shock will do nicely - thank you!

MaeZe
06-25-2016, 09:38 PM
Hypovolemic shock would not result in coma unless you were close to exsanguination, I don't think that's survivable. You might faint, everything going black until you laid flat and your body had a few minutes to compensate, but brief loss of consciousness is not a coma.

You get extremely weak, the circulation to your extremities shuts down, and inter and intracellular fluid shifts to your bloodstream to keep the pressure up. The kidneys could shut down if the condition lasted too long.

The symptoms would be tachycardia, shortness of breath, cold clammy skin (sweating shuts down), extreme weakness and yes, dehydration.

MaeZe
06-25-2016, 09:44 PM
I have a friend who lost more than half her blood, and refused a transfusion. Her full recovery took better than six months. It's my understanding that coma would not be a primary concern, unless of course there is brain damage from oxygen deprivation. Then that's a whole 'nother world of problem. Organ damage is of primary concern, and if that doesn't happen, what you're really left with is profound fatigue in functional anemia and chronic low blood-pressure. You simply don't have enough blood for a while to get all the oxygen and nutrients around to keep you lively. Fluid volume is tricky, because electrolytes can become imbalanced and cause a host of problems.

The immediate problem is hypovolemic shock (https://www.nlm.nih.gov/medlineplus/ency/article/000167.htm).

Here's some basic info on coma (http://www.webmd.com/brain/coma-types-causes-treatments-prognosis), if your need to tweak your scenario to get your guy in a coma.

Just one correction, (the rest is accurate) your blood pressure would not necessarily stay low, though it would be low at first. The body has a rapid compensation for hypovolemia due to blood loss, fluid shifts to the vascular space. That differs from hypovolemia due to dehydration where there is a lack of fluid in all the compartments (inside cells, between cells and bloodstream/lymph circulation). You end up with the equivalent of watered down blood, so you lose the capacity to transport oxygen until your red blood cells can be replaced.

Siri Kirpal
06-25-2016, 09:59 PM
Sat Nam! (literally "Truth Name"--a Sikh greeting)

I lost about 1/4 of my blood due to an enlarged vein and a tonsillectomy. Had I lost any more there would have been a transfusion, but didn't have one.

I did faint, but that was right after the surgery when they were trying frantically to pack the throat so I wouldn't bleed to death. I was dizzy for two weeks or so afterwards and couldn't do any strenuous exercise for about two months. Very low energy.

Blessings,

Siri Kirpal

Perks
06-25-2016, 10:09 PM
Just one correction, (the rest is accurate) your blood pressure would not necessarily stay low, though it would be low at first. The body has a rapid compensation for hypovolemia due to blood loss, fluid shifts to the vascular space. That differs from hypovolemia due to dehydration where there is a lack of fluid in all the compartments (inside cells, between cells and bloodstream/lymph circulation). You end up with the equivalent of watered down blood, so you lose the capacity to transport oxygen until your red blood cells can be replaced.

That makes sense. My friend who struggled to recover from such major blood loss may have just had a tendency toward low blood pressure anyway.

MaeZe
06-25-2016, 11:58 PM
That makes sense. My friend who struggled to recover from such major blood loss may have just had a tendency toward low blood pressure anyway.

Your body has multiple mechanisms to maintain hemostasis. Hypoxia, from the severe anemia triggers tachycardia. At the same time, vasoconstriction in the extremities increases blood pressure. There might be an extended period of time when orthostatic hypotension would be an issue. That would be a version of low blood pressure.

When you were sitting or lying down, the increased blood return to the heart would keep the pressure up as the heart raced along stimulated by hypoxia. You stand up and it takes a few seconds for everything to readjust. Blood increases to the legs, less return to the heart, a drop in blood pressure occurs until the vasoconstriction in the legs has a chance to re-equilibrate.

PeteMC
06-26-2016, 12:04 AM
That's brilliant, thanks folks.

So if I've got my guy passing out briefly, then coming round when they get him lying down but weak, dizzy, clammy, confused and very thirsty does that sound about right?

Quite happy for him to be breathless and weak as a kitten for a few months if need be.

Catherine_Beyer
06-26-2016, 12:21 AM
If you're going with actual 15th century medicine, everything is very rudimentary. There's no such thing as sterilization. There's no such thing as germ theory, although they understood dirty things got infected. Actual doctors designed most of their cures via astrology. A surgeon (which is what would be needed here) would be a barber-surgeon. The guy with the medical degree wouldn't get his hands dirty with such things.

History is wierd and terrifying and strangely awesome.

But you do say it's fantasy, so obviously your doctors can develop however you want them to. Just wanted to throw that out there if you're heavily leaning on history.

PeteMC
06-26-2016, 12:27 AM
Hi, yes the medic is basically a barber-surgeon rather than an actual doctor of medicine (it is fantasy but only just, there's no magic to speak of and it's pretty much a 15th century world).

One thing I've remembered - I had the doc say that if the wound goes bad the patient will die, as it's too high up for him to be able to amputate. Does that sound fair?

asroc
06-26-2016, 12:29 AM
Your body has multiple mechanisms to maintain hemostasis. Hypoxia, from the severe anemia triggers tachycardia. At the same time, vasoconstriction in the extremities increases blood pressure. There might be an extended period of time when orthostatic hypotension would be an issue. That would be a version of low blood pressure.

When you were sitting or lying down, the increased blood return to the heart would keep the pressure up as the heart raced along stimulated by hypoxia. You stand up and it takes a few seconds for everything to readjust. Blood increases to the legs, less return to the heart, a drop in blood pressure occurs until the vasoconstriction in the legs has a chance to re-equilibrate.

That only works if the integrity of the circulatory system remains intact, not if the patient is hemorrhaging freely. The more blood volume the patient loses, the less his body is able to maintain an adequate bloodflow to the brain, which manifests in increasingly serious neurological symptoms; dizziness, confusion, lethargy and eventuallu loss of consciousness and death. I the hemorrhage isn't stopped sooner or later (generally sooner and depending on the nature of the injury, very quickly) the body will pass the point of no return, at around 40% of blood volume lost. That stage is called uncompensated hypovolemic shock and is immediately life-threatening. Even if the bleeding were stopped right that moment there'd be no way the body could still compensate (replacing erythrocytes takes weeks.) If someone passes out from blood loss they're in, or very close to, uncompensated shock and they need immediate medical help in the form of a transfusion or they will invariably die.

MaeZe
06-26-2016, 12:47 AM
That's brilliant, thanks folks.

So if I've got my guy passing out briefly, then coming round when they get him lying down but weak, dizzy, clammy, confused and very thirsty does that sound about right?

Quite happy for him to be breathless and weak as a kitten for a few months if need be.
Perfect.

MaeZe
06-26-2016, 12:49 AM
That only works if the integrity of the circulatory system remains intact, not if the patient is hemorrhaging freely. The more blood volume the patient loses, the less his body is able to maintain an adequate bloodflow to the brain, which manifests in increasingly serious neurological symptoms; dizziness, confusion, lethargy and eventuallu loss of consciousness and death. I the hemorrhage isn't stopped sooner or later (generally sooner and depending on the nature of the injury, very quickly) the body will pass the point of no return, at around 40% of blood volume lost. That stage is called uncompensated hypovolemic shock and is immediately life-threatening. Even if the bleeding were stopped right that moment there'd be no way the body could still compensate (replacing erythrocytes takes weeks.) If someone passes out from blood loss they're in, or very close to, uncompensated shock and they need immediate medical help in the form of a transfusion or they will invariably die.

Why do you think it's uncompensated?

asroc
06-26-2016, 01:02 AM
Why do you think it's uncompensated?

Because PeteMC says his character passes out from blood loss. That's uncompensated shock. A patient in shock doesn't lose consciousness right away, then regains it, then exhibits the earlier shock symptoms, unless he lost consciousness due to something other than hypovolemia.

PeteMC
06-26-2016, 01:10 AM
Because PeteMC says his character passes out from blood loss. That's uncompensated shock. A patient in shock doesn't lose consciousness right away, then regains it, then exhibits the earlier shock symptoms, unless he lost consciousness due to something other than hypovolemia.

This is just due to me not knowing what I'm talking about - he doesn't *have* to pass out, I'll change it :)

Perks
06-26-2016, 01:34 AM
If it helps, my friend was losing blood while she was in the hospital. (She had started bleeding at home from a tear in her cervix, something your male main character won't have, obviously :) but I think the info might still be possibly helpful.)

She had a saline IV that might have had other medications in it, but was adamantly against a blood transfusion. So they were needing some sort of specialist to get down to ER for whatever they were going to do for her. While they were waiting (and this was only a very short amount of time) she was going through the weak, dizzy, clammy, thirsty stage, then she felt the confusion coming on. She was basically convinced that she was not far from being dead. The light was on its way for her.

So, she basically collared the young doctor who was monitoring her and all but throttled him, demanding that he start sewing NOW, anesthetist-specialist-whathaveyou be damned. She was so persuasive (she's brilliant and not to be defied) that he did what she said. Apparently it was agony. They still wanted to transfuse her and tried to convince her husband that she was being irresponsible, but she didn't want it. Her recovery was long and exhausting, but recover she did and she's absolutely fine. That was more than a dozen years ago.

MaeZe
06-26-2016, 02:30 AM
Because PeteMC says his character passes out from blood loss. That's uncompensated shock. A patient in shock doesn't lose consciousness right away, then regains it, then exhibits the earlier shock symptoms, unless he lost consciousness due to something other than hypovolemia.

So you don't understand the mechanisms that reestablishes blood volume with fluids from within the body then.

When the pressure within the blood vessels drops due to blood loss, it changes the fluid dynamics around the blood vessels. Since blood is leaving via a hole, the fluids in the intracellular space are not leaking out that hole. So the pressure in the intracellular space now becomes greater than the pressure within the blood vessels. Due to osmosis, water (saline in the case of the body) now flows into the bloodstream to compensate for the lost volume. It takes a minute, compensation is fast, but not as instantaneous as heart rate and vasoconstriction.

MaeZe
06-26-2016, 02:34 AM
Hypovolemic shock differs from septic shock, by the way. In septic shock fluid leaks into the tissues as the blood vessels become porous, allowing the large proteins to leak out, reversing osmosis. The same is true that hypovolemic shock from dehydration differs from blood loss. In dehydration there is no extra intracellular fluid.

asroc
06-26-2016, 05:01 AM
So you don't understand the mechanisms that reestablishes blood volume with fluids from within the body then.

Hemodynamics is a pretty big part of my job, so yes, I do. The problem isn't volume, it's oxygen. You need erythrocytes to carry oxygen, you've lost a whole lot of them because you're hemorrhaging and the body has no way of replacing those missing erythrocytes quickly enough. You can replace as much fluid as you want, if that fluid can't carry oxygen you're still going to die. In order to preserve the brain as long as possible the body will restrict the blood flow to the extremities and other non-essential parts, but eventually the brain will also experience hypoxia because there aren't enough erythrocytes to go around anymore. That's when you lose consciousness and it happens last. If you lose consciousness due to blood loss and don't get medical attention right away, you will not wake up.

MaeZe
06-26-2016, 05:27 AM
Hemodynamics is a pretty big part of my job, so yes, I do. The problem isn't volume, it's oxygen. You need erythrocytes to carry oxygen,...
Perhaps you are imagining something different going on here. You seem to be sticking with the OP's description of a coma. We've already passed that and Pete has changed the scenario so that the character merely passes out briefly, regains consciousness once flat.

In this discussion of the analysis of Jehovah's Witness patients with anemias, they found "Most survive with low hemoglobin – 1.5 - 1.7 grams per deciliter." (http://www.petproject.pathology.vcu.edu/pdfs/08-Shander.pdf). That even surprised me. Granted those folks got lots of support such as oxygen and blood substitutes. Still, that's almost all your red cells lost.

Beyond that, I'm not going to argue with you.

asroc
06-26-2016, 05:56 AM
Perhaps you are imagining something different going on here. You seem to be sticking with the OP's description of a coma. We've already passed that and Pete has changed the scenario so that the character merely passes out briefly, regains consciousness once flat.



Which is inconsistent with the mechanism of injury he has described. This is how a body reacts when you get up too quickly in the morning, not when hit in the thigh with a shrapnel.

Catherine_Beyer
06-26-2016, 06:09 AM
Hi, yes the medic is basically a barber-surgeon rather than an actual doctor of medicine (it is fantasy but only just, there's no magic to speak of and it's pretty much a 15th century world).

One thing I've remembered - I had the doc say that if the wound goes bad the patient will die, as it's too high up for him to be able to amputate. Does that sound fair?

Depends what you man by "goes bad." People can survive infections. All depends how bad the infection is and how strong his immune system is. But, yeah, I would guess there's a limit as to how high an amputation could go. But amputations were horrible anyway. You did not hve a great chance of surviving them.

"In the Middle Ages a leg amputee above the knee would not have survived such an amputation due to bleeding. Only amputees below the knee had a chance to survive (if they had luck)." http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071498/

MaeZe
06-26-2016, 06:24 AM
That's cool, Catherine. Great sleuthing.

MaeZe
06-26-2016, 06:52 AM
Hi, yes the medic is basically a barber-surgeon rather than an actual doctor of medicine (it is fantasy but only just, there's no magic to speak of and it's pretty much a 15th century world).

One thing I've remembered - I had the doc say that if the wound goes bad the patient will die, as it's too high up for him to be able to amputate. Does that sound fair?

Everything there sounds fair. The nice thing about fiction and medical science is you can tailor the wound to the scene you want.

Pick one or more branches of the femoral artery (http://image.slidesharecdn.com/antcmprtmntofthigh-151205162442-lva1-app6891/95/anterior-cmpartment-of-thigh-14-638.jpg?cb=1461828707). You don't need to name them but you can describe the wound accordingly.

More relevant history: Not everyone with a war wound in the Crimean War died of sepsis. Florence Nightingale kept track and kept records she later put in a graph. Most soldiers died of disease rather than their wounds.

Florence Nightingale: The passionate statistician (https://www.sciencenews.org/article/florence-nightingale-passionate-statistician)

By the time Nightingale left Turkey after the war ended in July 1856, the hospitals were well-run and efficient, with mortality rates no greater than civilian hospitals in England, and Nightingale had earned a reputation as an icon of Victorian women.

Most people think Nightingale was no more than the kind nurse with the lamp but in reality she was one of the first scientists to recognize wound hygiene had a significant impact on survivability and wound healing.

And in 1860, the germ was only beginning to take hold in the medical community. For example, despite the meticulous evidence collected by John Snow re the epidemiology of the London cholera epidemic and presented to his peers, it was a full ten years more before they gave up the miasma theory of bad air.

[/end sidetrack] :D

CWatts
06-26-2016, 04:45 PM
Hi, yes the medic is basically a barber-surgeon rather than an actual doctor of medicine (it is fantasy but only just, there's no magic to speak of and it's pretty much a 15th century world).

One thing I've remembered - I had the doc say that if the wound goes bad the patient will die, as it's too high up for him to be able to amputate. Does that sound fair?

One important thing to remember is what kind of shrapnel was it? (Note that the term itself is 19th century, named after Henry Shrapnel, a British artillery officer from the Napoleonic Wars who invented an exploding shell.) I'm assuming it's the metal debris we typically think of, but it could be anything sent airborne in an explosion. One of the big risks during the Age of Sail was the wooden splinters/stakes sent flying when cannonballs hit the hull, the oak would bend but break on the inside and anyone nearby could get impaled. Same could probably happen in buildings, etc. Also, is your guy wearing armor? What could have happened is the armor bent into the wound and he doesn't start bleeding out until someone removes it. That could buy him some time.

Re: the blood loss - I don't know how much blood I lost with my miscarriage (again, something your dude wouldn't have to deal with) but I fainted twice for maybe a minute each time, once when we were waiting for the ambulance and again in the ER. I got a couple bags of saline but did not need a transfusion. Some of that could have been panic. I did feel really weak and dizzy, also thirsty. One of the strangest things was that my hands and feet kept shaking around the time that I fainted. I guess that could be psychological, or from the reduced blood flow? They did feel like ice. I also felt cold, though some that was from the saline which was cold or at least room temperature and I could feel the cold going through my veins.

PeteMC
06-27-2016, 12:15 PM
This has been brilliantly helpful, thank you all so much but please don't have a complicated medical argument (that's lost me now anyway!) on my account :)


Her recovery was long and exhausting, but recover she did and she's absolutely fine. That was more than a dozen years ago.

I'm glad your friend made it.


"In the Middle Ages a leg amputee above the knee would not have survived such an amputation due to bleeding. Only amputees below the knee had a chance to survive (if they had luck)." http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071498/

Yeah that's what I thought - thanks for the link!


One important thing to remember is what kind of shrapnel was it? (Note that the term itself is 19th century, named after Henry Shrapnel, a British artillery officer from the Napoleonic Wars who invented an exploding shell.)

Oh damn, I hadn't even thought of that! The "shrapnel" was from rudimentary thrown bomb, something like a petard - which I know is 16th century not 15th, but like I said this is fantasy not historical fiction so I'm giving myself a bit of wiggle room with that sort of thing. I'll probably have to call the debris something else now, though...

I'm glad you got better too, btw - thanks for sharing your story!

GeorgeK
06-27-2016, 08:16 PM
I actually took care of a Jehovah's Witness with massive bleeding (bled down to a hemoglobin of 3 after a motor vehicle accident). We sewed what was sewable and then put her in the hyperbaric chamber and exceeded safety protocols to make sure she'd get enough oxygen and she walked out of the hospital about 6 weeks later. Of course she praised Jesus and thought we were devils, but whatever...

Blood transports oxygen. Without enough oxygen everything dies.
Coma is a result of brain injury not specifically loss of blood. As have others mentioned rather than a coma it would be better if every time the character tried to get up he/she would faint, would be better. Hemoglobin ( for ease of simplicity a red blood cell) lives roughly 90 days. That is what carries oxygen. Generally massive blood loss will result in increased production of RBC's to the point that someone who manages to survive without modern medicine, will probably be barely ambulatory at 6 weeks and back to full health at 3 months, assuming no other injuries.

PeteMC
06-28-2016, 01:19 PM
Perfect, thanks George!