How fast a person can bleed to death is a very common question among authors and I’ve done several posts on the topic. About a month ago, I got a comment asking a variation of the question.
It’s as follows:
Although I’ve worked in an animal clinic for years, I wasn’t sure how much of what I’d seen there translated to the human side. I’m currently editing someone’s manuscript and the injuries in a couple of scenes struck me wrong enough to do some digging before revision. A couple of things I’m still looking for is how long a person remains conscious with arterial or venous bleeding (in one scene, this is from a femoral injury) and whether/how much accelerated heart rate from exertion speeds bleeding?
It’s hard in medicine to give actual time frames. The best demonstration I ever saw of how fast it took to bleed out was from a physician that drilled a hole into a two liter bottle of pop and then squeezed it mimicking a heartbeat. He said the size of the hole could be equated with an injury to the popliteal artery (which is behind your knee) and that bottle was empty in about two minutes.
Devastating injuries to larger arteries (your aorta for instance) can cause the patient to bleed out (hemorrhage or exsanguinate) in 1-2 minutes. It’s fast. For instance, if you rupture your descending aorta in a hospital and they know exactly what is wrong with you, and even have a couple of IV’s in place, your chances of survival are still not awesome.
Some general rules:
Arterial bleeding is faster than venous bleeding. This is because the pumping action of the heart causes more brisk blood loss. That being said, all bleeding can lead to death if not controlled. It’s probably safe to assume that bleeding from an artery without any intervention could lead to unconsciousness in one to three minutes and death in under five minutes.
Uncontrolled venous bleeding might take upwards of twenty minutes or days. Again, if not controlled in any way. Again, this could be variable. The author has a lot of leeway.
Does a fast heart rate accelerate bleeding? Yes. The faster your heart beats, the more blood spills, particularly from an arterial bleed. This is a double edged sword because your body will compensate by increasing your heartbeat during blood loss to compensate for all those red blood cells on the pavement and not in your body carrying oxygen.
Here are other posts on the topic of blood loss:
What other questions do you have about characters bleeding to death?