Emergency bleeding control

Emergency bleeding control describes actions that control bleeding from a patient who has suffered a traumatic injury or who has a medical condition that has caused bleeding. Many bleeding control techniques are taught as part of first aid throughout the world, though some more advanced techniques such as tourniquets, are often taught as being reserved for use by health professionals, or as an absolute last resort, to mitigate associated risks, such as potential loss of limbs. To manage bleeding effectively, it is important to be able to readily identify types of wounds and types of bleeding.
Types of wounds.
Wounds are normally described in a variety of ways. Descriptions may include wound size (length) and thickness; plainly visible wound characteristics such as shape and open or closed; and origin, acute or chronic. The most common descriptors of wounds are these:
Blood vessels affected.
External bleeding is generally described in terms of the origin of the blood flow by vessel type. The basic categories of external bleeding are:
External wound management.
The type of wound (incision, laceration, puncture, etc.) has a major effect on the way a wound is managed, as does the area of the body affected and presence of any foreign objects in the wound. Key principles of wound management are:
Elevation.
Elevation was commonly recommended for the control of haemorrhage. Some protocols continue to include it, but recent studies have failed to find any evidence of its effectiveness and it was removed from the PHTLS guidance in 2006.
Direct pressure.
Placing pressure on the wound constricts the blood vessels manually, helping to stem blood flow. When applying pressure, the type and direction of the wound may have an effect, for instance, a cut lengthways on the hand would be opened up by closing the hand into a fist, whilst a cut across the hand would be sealed by making a fist. A patient can apply pressure directly to their own wound, if their consciousness level allows. Ideally a barrier, such as sterile, low-adherent gauze should be used between the pressure supplier and the wound, to help reduce chances of infection and help the wound to seal. Third parties assisting a patient are always advised to use protective latex or nitrile medical gloves to reduce risk of infection or contamination passing either way. Direct pressure can be used with some foreign objects protruding from a wound; padding is applied from each side of the object to push in and seal the wound - objects are never removed.
Pressure points.
In situations where direct pressure and elevation are either not possible or proving ineffective, and there is a risk of exsanguination, some training protocols advocate the use of pressure points to constrict the major artery that feeds the point of the bleed. This is usually performed at a place where a pulse can be found, such as in the femoral artery. There are significant risks involved in performing pressure point constriction, including necrosis of the area below the constriction, and most protocols give a maximum time for constriction (often around 10 minutes). There is particularly high danger if constricting the carotid artery in the neck, as the brain is sensitive to hypoxia and brain damage can result within minutes of application of pressure. Pressure on the carotid artery can also cause vagal tone induced bradycardia, which can eventually stop the heart. Other dangers in use of a constricting method include rhabdomyolysis, which is a buildup of toxins below the pressure point, which if released back into the main bloodstream may cause kidney failure.
Tourniquet.
Another method of achieving constriction of the supplying artery is a tourniquet - a band tied tightly around a limb to restrict blood flow. Tourniquets are routinely used to bring veins to the surface for cannulation, though their use in emergency medicine is more limited. Tourniquet use is restricted in most countries to professionals such as physicians and paramedics, as this is often considered beyond the reach of first aid and those acting in good faith as a good samaritan. A key exception is the military, where many armies carry a tourniquet as part of their personal first aid kit.
Improvised tourniquets, in addition to creating potential problems for the ongoing medical management of the patient, usually fail to achieve force enough to adequately compress the arteries of the limb. As a result, they not only fail to stop arterial bleeding, but may actually increase bleeding by impairing venous bloodflow.
Clotting agents.
Some protocols call for the use of clotting accelerating agents, which can be either externally applied as a powder or gel, or pre-dosed in a dressing or as an intravenous injection.
These may be particularly useful in situations where the wound is not clotting, which can be due to external factors, such as size of wound, or medical factors such as haemophilia.
Recombinant factor VIIa (rFVIIa) is not, as of 2012, supported by the evidence for most cases of major bleeding. Its use brings a significant risk of arterial thrombosis, and therefore it should only be used in clinical trials or with patients with factor VII deficiency.
Internal wound management.
Internal wounds (usually to the torso) are harder to deal with than external wounds, although they often have an external cause. The key dangers of internal bleeding include hypovolaemic shock (leading to exsanguination), causing a tamponade on the heart or a haemothorax on the lung. The aortic aneurysm is a special case where the aorta, the body's main blood vessel, becomes ruptured through an inherent weakness, although exertion, raised blood pressure or sudden movements could cause a sudden catastrophic failure. This is one of the most serious medical emergencies a patient can face, as the only treatment is rapid surgery.
In the event of bleeding caused by an external source (trauma, penetrating wound), the patient is usually inclined to the injured side, so that the 'good' side can continue to function properly, without interference from the blood inside the body cavity.
Treatment of internal bleeding is beyond the scope of simple first aid, and a person giving first aid should consider it potentially life-threatening. The definitive treatment for internal bleeding is always surgical treatment, and medical advice must be sought urgently for any victim of internal bleeding.