Blood loss and impact

PTeppic

PTeppic

Reetou Diplomatic Corp
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May 31, 2001
Messages
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One of the bugbears I have with fair sections of SFF (and TV/movies) is the near-immortality of characters unless the plot requires the injury to continue the story. Trying to improve my own work, I'm curious if anyone with medical knowledge can pad out my understanding.

For example, a really serious wound could spill up a pint of blood (for example) which I'm using as an example since that's what many countries have donors give. After such a procedure, even standing up can lead to fainting etc. Using that volume as an example, what physical effects would there still be one, two and four weeks later? Does it affect speed, stamina, both or neither?
 
Speaking as a blood donor, I'm usually fine a few hours later and have never had trouble with fainting, etc. That said I'm a (reasonably) fit and healthy man in his mid twenties.
 
I think Blood Donors only give about ½ a pint (used to be more I think.) They are allowed to go more often now (about every 3 months I think.) I speak as having given many pints as a donor, but not for a while. I also used to get a lot of nose bleeds as a child and could easily lose ½ pint of blood.

Having said that, there always seems to be one person who faints when I've been, but that probably isn't from blood loss, but rather psychosomatic.

Also small amount of blood can look like lot more than it really is though. As a liquid when is is spilled it spreads out thinly to cover a wide area.

Speaking as a First Aider, bleeding is very serious as it can lead to medical Shock if there is insufficient blood left to carry Oxygen to the vital organs, and therefore bleeding must be treated.

Loss of 0.5 litres/ 1 pint has little or no effect.

Loss of 2 litres/ 3½ pints causes the release of hormones such as Adrenaline, quickening the pulse, inducing sweating. Small blood vessels in non-vital areas, such as the skin, shut down to divert blood and the Oxygen it carried to the vital organs. Shock becomes evident.

Loss of 3 litres/ 5 pints is half of the normal level in the body of an average adult. As the blood loss approaches this level the pulse at the wrist may become undetectable. The casualty will usually lose conciousness, breathing and heart may fail.
 
At least people who get stabbed with a knife/sword/whatever actually show an effect usually. Even if it isn't much.

Blunt impacts are lucky if they manage to stun someone for a few seconds or have them say owch. Plus they don't bleed, except the occasional bloody nose. The club wavers out there definitely have the shorter end of the stick in combat.
 
Not that it answers your question, but when I took EMS training the instructor said that if you came upon a scene of mayhem and someone was lying in a pool of blood six feet across, not to worry. That would only be about a pint. I've never tested it.
 
PTeppic said:
One of the bugbears I have with fair sections of SFF (and TV/movies) is the near-immortality of characters unless the plot requires the injury to continue the story. Trying to improve my own work, I'm curious if anyone with medical knowledge can pad out my understanding.

For example, a really serious wound could spill up a pint of blood (for example) which I'm using as an example since that's what many countries have donors give. After such a procedure, even standing up can lead to fainting etc. Using that volume as an example, what physical effects would there still be one, two and four weeks later? Does it affect speed, stamina, both or neither?
Click to expand...

My understanding, is that up to a third of your blood can be lost, and an individual can still function, but shock can be a bigger killer in many cases, so effects from rapid blood-loss are serious, but not a pint or so. Gunshot wounds in particular - unless they have hit a major organ or artery - can, if the victim isn't stabilised speedily, cause the patient to shut down from shock. I was lead to believe this was one of the reasons to reduce the calibre of UK military rounds from 7.62mm, as the replacement rounds in effect took out 3 on the battlefield. The soldier hit, his buddy caring for him and a medic. With the older larger calibre rounds, if it didn't kill the soldier who was hit, the trauma from the injury would usually cause shock to set in pretty quickly. Not a pretty scenario, of course, but as it was explained to me.

Also, as I'm sure you know - just like the heroes riddled with bullets and still fighting on, and every car exploding :rolleyes: - Hollywood uses poetic licence when we see someone shot and flying across a room. It would be a fair size round that managed to lift someone off their feet and throw them physically off their feet when shot. The mass of the projectile - if a standard bullet - and its velocity, when hitting a human, make it an impossibility.
 
billhafan said:
Also, as I'm sure you know - just like the heroes riddled with bullets and still fighting on, and every car exploding :rolleyes: - Hollywood uses poetic licence when we see someone shot and flying across a room. It would be a fair size round that managed to lift someone off their feet and throw them physically off their feet when shot. The mass of the projectile - if a standard bullet - and its velocity, when hitting a human, make it an impossibility.
Click to expand...

The Mythbusters (US cable show) have done several episodes on Hollywood gunshot and explosive myths.

They tried everything from a round to 9MM round to .50 calibre to a shotgun (all using pig carcasses) and there was no weapon that even threw the target a few inches. (None of them blow up cars either-even when using incendiary ammo on gas tanks)
 
Some interesting points.

What I was hoping someone might know would be the impact of the temporary red blood cell loss on physical ability. Wiki tells me that (on average) it takes around 5 weeks for the bone marrow to produce the red cells back to normal levels. Inevitably, to me, that implies reduced abilities. I'm wondering what? Getting winded whilst trekking over the mountains to escape the incident? Speed and agility whilst fighting the next X encountered whilst making said trek? Etc. Or am I being too bogged down?
 
I guess at the end of the day, we write fiction; so a degree of incredulity is allowed or even called for - it's what gives the reader some escape. I try in my writing - obviously like yourself - to research many aspects of my story-line, even using authentic name-places etc. as required, and also weapons specs if called for, but the bottom line is that if your character has been shot, stabbed or hurt enough to lose up to a third of his blood he could still function. How well is going to be down to your imagination as I know there are huge differences in stamina amongst individuals in real-life, especially under duress, so there can be just as many in fiction - or more? ;) Would also depend greatly on the fitness of the individual beforehand, and treatment received afterwards - you could possibly slow the character up by 15-20%? or maybe write past it, and see how the character fares, then re-visit?
 
I guess it would be the reverse 'Lance Armstrong' effect - the lack of haemoglobin, and oxygen-carrying capabilities would hamper anything more than moderate exercise, because blood gases would be more slowly exchanged, and tissues would not be able to function as efficiently, so breathlessness would result. The lack of blood volume would lower blood pressure (keep drinking water to raise the volume temporarily as a plot line). But I'm uncertain how long it would last. And I think I remember my physiology lectures correctly, that the demand put on the body results in more red cells produced more quickly. ie lose a pint of blood and lie in bed to recover and the body does it slowly. Lose a pint and be forced to march/climb/exercise and the body goes into overdrive to produce them.
 
Immediately after being injured (depending upon severity), don't try hiking/climbing over mountains unless you really have to. I had to do a long walk out after a fall once and I hurt for days.

With time, you might be able to much more, dependent upon a few factors, including:

severity of the injury and how it was treated;
risk of opening the wound if not healed;
strength and fitness (hiding up with low food/liquid resources isn't the best);
necessity (might die or will die); and
pace (you might have to take it slower, not least due to pain, but again, necessity).

Your abilities, including speed and stamina, could still be impaired, but you might be better able to get out after resting even a short time depending upon how bad it is. A week or two could make a considerable difference.

A lot of it comes back to how much you need to do this. You can work through pain if you have to, but pain also tells you there's a problem. Of course, prolonged activity may exacerbate an injury, which can also be a plot device. Apologies for the caveats breeding caveats in this post. ;)
 
In terms of pain - I've known several serious athletes and they train through painful injuries (partially because they love running so much they will put up with pain in order to do it).

Reaction time - I used to do a lot of fencing which does rely on fast reaction time. If you are a bit under the weather - cold, onset of a virus, you can think you are well enough to go fencing and then get hammered in fights because your reaction time is down.
 
 
I once gave an emergency blood donation. I did not eat breakfast. I was chatting with the person who had put the IV in my arm. After a minute or two sounds suddenly seemed far away, my own voice sounded alien, and my body felt heavy. I felt high. He leaned forward in his seat smiling, thinking my light-headedness was funny and immediately chocked it up to anxiety--it was not. I laid down, had a couple fruit juice boxes. The next day I went running, it got tired faster than usual.

I talked to a man who almost bled to death internal bleeding when an artery painlessly burst in his digestive track. He thought it would have been a rather peaceful, relaxing way to die.
 
Okay, here's one from my current WiP. One of my side characters went I saved the main characters by making them to feed on his blood. So Jane wakes up and finds out Jaq suckling his wrist. She immediately tore away the hand and feels the jugular vein. No pulse. So she understands that Jaq drank too much. The question is, as they're in the back of an APC (armoured personnel carrier):

a) is she going to be able to resurrected him through her training as senior emergency nurse?
b) with a blood loss of 80 to 90 percent, is it too much?
c) if she injects a bag or two of IV liquid, is it going to be enough?
d) will the heart start from a cardiac shock?
 
In a future wip I have an alien stab a secondary character and gives the main character until she dies to decide something.

I haven't looked too much into that subject matter yet, but I did find this
http://en.wikipedia.org/wiki/Exsanguination
people can die from losing half or two-thirds of their blood; a loss of roughly one-third of the blood volume is considered very serious
Click to expand...
 
The problem, how I see it, is that since such massive blood loss and stoppage of hearth, there's almost no way to get blood in the system. And as saline cannot substitute plasma, it's never going to start pumping even if give Jane a chance to jump start the poor geezer. So I guess I have two options,

1) Do something seriously stupid and potentially dangerous and try to inject liquid directly to hearth before the jump start.
2) Let the character die and move on.
 
ctg said:
Okay, here's one from my current WiP. One of my side characters went I saved the main characters by making them to feed on his blood. So Jane wakes up and finds out Jaq suckling his wrist. She immediately tore away the hand and feels the jugular vein.You won't get a pulse from a vein, only an artery. Try the carotid in the neck No pulse. So she understands that Jaq drank too much. The question is, as they're in the back of an APC (armoured personnel carrier):

a) is she going to be able to resurrected him through her training as senior emergency nurse? Resurrect, no. Keep him alive, maybe.
b) with a blood loss of 80 to 90 percent, is it too much?Given this, take the above with a pinch of salt. He's doomed, assuming he's human.
c) if she injects a bag or two of IV liquid, is it going to be enough? With that amount of blood loss, you'd need blood. Fluids will keep the blood pressure up, but it won't carry oxygen. But if he'slost 80-90%, he's already dead anyway
d) will the heart start from a cardiac shock? Very unlikely
Click to expand...

The above answers all assume your character is human and not superhuman, and your estimate of 80-90% loss is accurate. If you want him to live, as Glitch says, losing a third of your blood is sufficient to almost kill him, but give him some chance.
 
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