Given the media outcry against gun ownership, it's easy to forget the wounds that are caused by knives and other sharp instruments. Trauma incurred from these injuries may be minor or major; penetrating trauma such as caused by a stab wound should not be discounted as a major injury; it can be life-threatening, depending on the organs and blood vessels damaged.
Penetrating trauma is divided into perforating and non-perforating. A perforating wound is one in which the object causing the damage goes into one side of the body and then exits through the other side. A wound from .223 or NATO .556 would, commonly, be an example of this type of penetrating trauma. One of my first classes in medical school showed a slide of Major General Henry Barnum, who received a minie ball through the hip in the battle of Antietam. Years later, he could still pass a thin rod from the entry wound all the way out the other side. General Barnum's hip, incidentally, is still on display in the National Museum of Medicine, where it has been for over 100 years.
Bullets and other high-speed projectiles cause damage related to the shock wave produced as the bullet passes through the body. This is called cavitation. Many bullets will fragment in the body as well, sometimes causing damage further from the entry wound than expected. Luckily, low speed projectiles such as knives will not do this. Your concerns are related specifically to the area of entry and the structures located directly in the path of the offending instrument.
Stab wounds are an example of a non-perforating wound: the projectile causing the damage enters the body and either stays there or exits where it entered. Most knife wounds would fit in this category, as the knife doesn’t pass entirely through and out of the body. Some sharp instruments might do this, say a crossbow bolt or a spearhead, but let’s assume that you’ll be unlikely to see these. Most knife wounds you'll see will be minor lacerations. Blood loss and failure of damaged organs will be the major issue to deal with.
A little about blood: Blood carries oxygen to the tissues and organs and removes waste products. It is made up of several components, including:
• · Red blood cells: These cells carry oxygen to body tissues.
• · White blood cells: These cells work to, among other things, fight infection and disease.
• · Platelets and other clotting factors: These allow blood to coagulate and lessen blood loss.
• · Plasma: A yellowish liquid in which the above are suspended.
Your immediate action upon encountering a victim of a wound with a sharp instrument may save their life. Bleeding from arteries and internal organs can be very brisk. If you are a typical 180 lb. (about 70 kg.) adult, you have approximately 9-10 pints (about 5 liters) of blood in your body. Athletes and those living at very high altitudes may have more. You can’t afford to lose more than 40% of total blood volume without needing major resuscitative efforts. To get an idea of how much blood this is, empty a 2 liter bottle of fruit punch or cranberry juice on the floor. You’ll be surprised at how much fluid that represents.
Hemorrhage (bleeding) is classified by the American College of Surgeons (of which I am a Fellow) as follows:
Class I: Hemorrhage is less or equal to 15% of blood volume (1.5 pints/3/4 liter) in an average adult male. A person donating 1 pint of blood is giving slightly less than 0.5 liters, for example. At this level there are almost no signs or symptoms, although some may feel vaguely faint.
Class II: Hemorrhage is 15 to 30% loss of total blood volume (2-3 pints/1-1.5 liters). The body tries to compensate at this point with, among other things, a faster heartbeat to speed oxygen to tissues. This patient will appear pale and skin will be cool. They will feel weak.
Class III: Hemorrhage is 30 to 40% loss of total blood volume (3-4 pints/1.5-2 liters). At this point, the heart will be beating very quickly and is straining to get enough oxygen to tissues and blood pressure is low. Smaller blood vessels in extremities are constricting to keep the body core circulation going. This patient will be confused, pale, and in hypovolemic (low blood volume) shock. Blood transfusion is usually necessary.
Class IV: Hemorrhage is more than 40% of total blood volume (greater than 4 pints/2 liters). The heart can no longer maintain blood pressure and circulation. Without major resuscitative help at this point, organs will fail and the patient will likely be comatose and die.
In most circumstances, sharp instrument injuries will be minor. After controlling bleeding, your goal is to clean the wound thoroughly and dress it. Wound closure may be an option in some wilderness cases, but most backcountry stab wounds will be dirty and should be left open (subject of another article).
If you're attending to an actively bleeding wound from a sharp object, you will need a level head and quick action. This is, sometimes, not as easy as it sounds; most people not accustomed to dealing with these issues on a daily basis will experience a type of paralysis that may waste precious time. If modern medical care is available, contact emergency services immediately.
In the meantime, follow these steps:
· - Assess the safety of the situation. Make sure the situation is secure; it makes no sense for you to become the next casualty.
· -Put on gloves if possible. Your hands are full of bacteria and you will reduce the risk of infection by doing so. Non-latex (nitrile) gloves are superior in avoiding allergic reactions to latex, more commonly seen than you’d think. If no gloves are available, plastic bags/wrap or, at least, hand sanitizers/soap will be useful if you have to touch the wound with bare hands.
· -Verify the victim’s breathing and mental status. Clear airways if obstructed and determine if they are alert enough to help you by following commands.
· Remove clothing carefully to fully inspect the wound and identify other injuries. Make sure that you have a bandage scissors or EMT shears in your medical pack.
· - Elevate the feet above the level of the heart and head (the “shock position”) to increase blood flow to the brain.
· - If the sharp instrument is still in the body, don’t remove it. It may be providing pressure on damaged blood vessels and decreasing the bleeding. Stabilize the wound in place with dressings or in any way you can. If there is no chance of emergency services reaching you, such as in a backcountry trip in an underdeveloped country, you may have to remove it at one point or another. Don’t do this unless you are where the bulk of your medical supplies are.
· -Apply pressure with some type of dressing, even your shirt if necessary. Most non-arterial bleeding will stop with steady pressure on the wound. If the sharp instrument is in place and help is on the way, place pressure down on either side towards the blade to prevent it from slipping out and decrease bleeding.
· -Elevate the injured area about the heart. Make it more difficult to pump blood out of the body.
· -Some recommend applying additional pressure with your other hand to major arteries about the level of the wound (especially for extremities). These areas are called “pressure points”. For example, a major artery (the popliteal artery) is found behind the knee. Pressure here might decrease bleeding from a lower leg wound. There is an entire map of pressure points for most parts of the body [that can be found with a quick web search.]
· - If this fails, consider applying a tourniquet to stop the bleeding. Tourniquets are to be used only when absolutely necessary, as they also stop the circulation of undamaged arteries and veins. This will cause damage or death of tissue beyond the level of the wound if left on too long. They also, after a very short time, hurt like a son of a gun. If a tourniquet is on, you may choose to loosen it after a period of time to determine if the body's clotting mechanisms have stopped the bleeding. Unfortunately, this can sometimes cause further bleeding, so this is mostly a strategy for when help in NOT on the way. If you are transporting a patient to a modern medical facility, make sure you mark a "T" on the victim's forehead or otherwise notify emergency personnel.
· - In certain circumstances, the use of blood clotting agents such as QuickClot or Celox may be helpful. They are effective in stopping bleeding, although they are sometimes difficult to clean out later. We keep these products in all our medical packs, even individual first aid kits.
· - Once bleeding has subsided, don’t remove a dressing unless you have to. There are clots that can be dislodged if you do, and this may restart the bleeding. Add additional dressings on top if help is on the way. In survival situations, you will eventually have to change and clean wound dressings.
· -Secure everything with a pressure dressing, of which there are various on the market. The Israeli Battle Dressing, known as The Emergency Bandage in the U.S., has a hinge which can apply up to 30 pounds of pressure if used properly.
· - Keep the victim warm: Throw a blanket or a coat over them. If help is coming, keep them as still and calm as possible to avoid further bleeding. Monitor breathing, pulses, and mental status.
· - An unconscious patient should be placed in the “recovery position”. This will, among other things, allow fluid to drain from airways and help them breathe.
All of the above may not be necessary if you practice preventative measures. In other words, don’t run with scissors. With some foresight, you may be able to avoid a mishap that could turn into a tragedy.
About the Authors: Amy Alton, A.R.N.P. and Joe Alton, M.D. (aka "Nurse Amy" and Dr. Bones" are the producers and hosts of the popular Doom & Bloom podcast.