Why are tying the tourniquets or restricting bandages not recommended or in fact to be avoided to treat a snakebite before getting the proper medical attention?
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asked Aug 22, 2016 at 14:29
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5Snake bite = maybe loose a limb. Tourniquet = pretty much guaranteed to loose a limb.– ShemSegerCommented Aug 22, 2016 at 14:38
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1ooh... tourniquets and snakebits, my favorite sources of medical mythconceptions! Weda, I think a distinction should be made re: crotalid vs elapid, as the first aid for the latter would be the pressure immobilization technique.– requiemCommented Aug 22, 2016 at 17:54
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8Tourniquets risk more than just the limb. Consider what happens in a limb that's had a tourniquet applied for hours. With no blood or lymph flow, a huge load of toxic waste products build up in the limb. When you release that tourniquet, all those waste products are going to flood the body. That right there can kill you.– Carey GregoryCommented Aug 22, 2016 at 22:57
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@requiem: Absolutely brilliant point. The best I can do is to restrict the question to Crotalid.– WedaPashi ♦Commented Aug 23, 2016 at 6:44
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2 Answers
There are several issues with tourniquets for snake bite:
It's likely too late anyway
The venom will spread rapidly though your system (as Weda says, the lymphatic system is the main carrier, not blood). The chances of you getting a tourniquet on before this has happened is minuscule.
It keeps all the venom in one place
Even if you do somehow manage to contain the venom, it's all in one place now! This means that a single area gets an incredibly high dose of venom. Bear in mind many snakes deliver a bite strong enough to kill several adult humans, now concentrate all that venom into a single limb. The damage caused is massive. The tissue dies and infection gets in.
The tourniquet is likely going to damage the limb as much as the bite
Stopping the blood is going to (obviously) starve the limb of blood. This is going to cause necrosis (dying off of tissue) which causes infection. Tourniquets are not to be used lightly. They should only ever be used as a last resort to prevent someone bleeding out. A limb that has had a tourniquet applied for a long period of time is a dead limb and will likely need to be amputated.
Eventually the tourniquet needs to be removed
So now you have large amounts of damaged tissue, etc in this single limb; eventually someone has to remove this tourniquet or else you're going to lose that limb anyway. Doing so releases all the venom and damaged tissue, necrosis, infection, etc. into your blood stream. Rather than containing the venom, you've concentrated it and released it anyway along with lots of other nasties...
The best thing to do if you get bitten, is to get antivenom FAST! Your priority should be this; don't waste your time or effort trying to suck the venom out or contain it. Simply get to the nearest antivenom ASAP.
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2Not only must a tourniquet eventually be removed, proper tourniquet procedure is tor it to me relieved at lest every 15 minutes, preferably more often. If attempting to stop venom, this largely defeats the purpose. Tourniquets are normally recommended in modern first aid only by those well trained in the use, and only for stopping massive blood loss or when it is the limb will be lost to save the person. With snake bites the tourniquet often causes more damage than the bite. Many people have suffered considerable damage from harmless snakes when well meaning people applied a tourniquet.– dlbCommented Aug 23, 2016 at 14:28
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5I can't provide a reference, but on my last tourniquet training (mid-2017, in UK) I was taught that relieving every 15 minutes is no longer considered best practice, and that a tourniquet should be locked tight until the patient is in a hospital environment where the release of normal blood toxins can be managed. Agreed that you should assume the loss of the limb when applying a tourniquet, and avoid them unless the alternative is the loss of the entire patient. Commented Jul 28, 2017 at 9:57
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3@TobySpeight You're right: never loosen a tourniquet. Doctors will administer medications that will help the body debride necrotic tissue. Also, as a result of improvements in medicine during the Gulf wars, we are now able to have soldiers be given a tourniquet, continue fighting, and later have the tourniquet removed and still preserve the limb, even after 6 hours. Much relies on the tourniquet itself, which we've discovered the width of it makes all the difference. A wide band is now the rage in tourniquet technology. Commented Aug 4, 2017 at 16:25
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I am confused about your second point. As I understand it, there are different types of snake venom, which have different effects. Some might attack the nervous system, others block certain hormone transmitters etc. Doesn't that mean that certain types of venom might not affect certain types of tissue at all, i.e. containing them in one limb is no problem at all? Commented Feb 17, 2019 at 11:43
I keep on telling people that they should never try to restrict the blood flow by using a tourniquet or a tight restricting bandage. It has been a stupid myth among people, visualizing that the snake bites a person and the venom gets mixed in blood like you dip a color paint brush into the water bowl and water turns into a different color. This is not how it happens.
Most of the snake bits are Subcutaneous, sometimes Intramuscular (Ones that you might have taken on your hips when you were kid) and very very rarely Intradermal (Just a scratch along the layers of the skin) rather than being Intravenous (Injecting liquid substances directly into a vein), unless the snake fangs are so big and you are utterly unlucky.
Now how does it correlate to sucking venom out of a snake bite? Taking a deeper dive, you'd need to know how the venom gets into the victim's blood, what People usually call as Envenomation which means absorption of the venom into the bloodstream. The venom is absorbed firstly into Lymphatic System, which is a part of the Circulatory system. Again, Lymphatic system does not carry bloodstream, it carries Lymph. Lymph gets mixed with Blood at left or right Subclavian vein. But before that, the Lymph is passed through Lymph Nodes. Lymph nodes act like a filter for something that doesn't belong to the body, something which is foreign. But, these are not meant to deal with any kind of Toxins. So they get exhausted and that results in swollen or tender lymph nodes. That exactly why the ones who survive a snake bite sustain significant damage to Lymphatic system.
Ask anyone who has had a serious scorpion bite, or tell your doctor that you have been bitten by something you don't know about. The doctor might check your body for swelling around groin or armpits. That's where the Lymph nodes are. Later the toxins reaching Kidneys do their damage.
The point is, does the venom directly gets transported through bloodstream, no, it doesn't! using a tourniquet to stop the blood flow is a useless thing to do. The aim should be to prevent lymphatic spread rather than restricting the blood supply altogether.
The reason behind roughly explaining how it takes place, is to clarify why do should do certain things.
answered Aug 22, 2016 at 14:31
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If the snake happened to hit or nick a vein or artery then venom would enter the blood stream but still tourniquet or a restricting bandage is not recommended. Commented Aug 22, 2016 at 15:46
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Why do you think a tourniquet will not stop/slow lymphatic spread? There are SOO... Many variables. Commented Aug 22, 2016 at 16:17
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1@JamesJenkins One of the variables is a limb needs blood flow to say alive. Commented Aug 22, 2016 at 16:49
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And some snake bites can prove fatal in less time then it takes to loose a limb to bloodflow. I am not saying your answer is wrong, in some cases. But different cases it is. Commented Aug 22, 2016 at 17:07
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1@JamesJenkins It is not my answer. Are you finding any modern medical recommendation to use a tourniquet for even the most deadly snake bite? Even if you can die in 30 minutes that alone is not rational to use a tourniquet. It is not necessarily related to how fast can a snake bit kill you. Commented Aug 22, 2016 at 19:20