WOUNDS

Everyone suffers a wound from time to time. Most of these are simple injuries which heal without any difficulty, but others can sometimes be fatal or result in some kind of permanent disability or disfigurement.

The seriousness of a wound depends on what structures in the body are injured rather than on the wound's actual size. A small puncture to a vital organ like the heart or brain may cause death, while a large wound involving only skin may have no lasting effects.

TYPES

Wounds fall into several categories: abrasions, contusions, lacerations, incisions and punctures. Gunshot wounds can have one or more features of these, but are included here because they very often require special treatment.

ABRASION

An abrasion is a graze. An abrasion occurs when the skin is rubbed forcibly against something rough. The outer layer of the skin, the epidermis, is rubbed away, exposing the deeper layer, the dermis. This deeper layer contains small blood vessels, so a little bleeding occurs. It also contains many nerve endings which are left exposed by the graze, resulting in the intense stinging pain that accompanies such wounds.

CONTUSION

A contusion is a bruise. It occurs when a part of the body is struck by something blunt, leaving the skin unbroken. The tissues beneath the skin, the fat, muscles and internal organs, receive the force of the blow. Small blood vessels in these tissues burst, and blood leaks into the tissues. This causes the tissues to swell and become tight; when this happens, further bleeding stops, but the tissue tightening causes pain.

Blood which is circulating through the body is a bright red colour. Blood which seeps into the tissues in a contusion gradually loses most of the oxygen which it is carrying, and as it does so it turns a bluish-black colour. This is why bruises are dark blue to black at first. Later the blood is broken down and reabsorbed by the body, and the bruise gradually becomes greenish-yellow or light yellow. Occasionally the blood collects in a pool among the tissues rather than sweeping out into the tissues; this is called a haematoma.

GUNSHOT WOUNDS

These, and wounds caused by bomb blast shrapnel, cause extensive damage to tissue and are particularly likely to become infected.

The amount of damage a bullet causes obviously depends on the actual tissues which the bullet passes through. But in addition, the speed of the bullet is important. Low-velocity bullets, that is, those fired by hand-guns, tend to damage only those tissues which the bullet track passes through. High-velocity bullets, that is, most rifle bullets, create a 'shock wave' as they pass through tissues. In such cases tissue may be badly damaged even at some distance from the bullet track itself.

LACERATION

A laceration means a tear, but it is commonly used to refer to any sort of cut. Lacerations can vary from a trivial wound which just goes through the skin, to very deep wounds involving important structures such as nerves, blood vessels and tendons. Lacerations can occur through contact with something sharp like a knife or a piece of glass, or they can occur with a blunt blow - for example striking the forehead on the floor may split open the skin.

INCISION

This word is commonly used to mean a cut made with a clean sharp instrument as in an operation. Therefore the only difference between an incision and a laceration is that an incision is 'intentional', as in a surgical operation, and the damage is limited to the actual tissues which were intended to be cut.

PUNCTURE

A puncture is a wound made by a pointed object such as a needle or a thorn. Punctures are deeper than they are wide, and serious damage can be done to deep structures without much obvious damage on the surface. Because these wounds are often made by long thin objects, it is common for a little piece of the object to break off inside, leaving a 'foreign body'.

WOUND HEALING

Wounds heal in one of two ways: they either resolve completely, leaving no trace, or they heal by scarring. A wound can heal without leaving a trace only if the wounded tissue has not been completely disrupted. Grazes heal in this way because only the top layer of the skin is rubbed away, leaving behind the deeper layer. This deeper layer contains the cells which multiply and migrate to the surface to form the top layer, and when the top layer has been removed this process continues until normal skin has been restored. Occasionally the site of a deep graze can be seen years later as a slightly pale area of skin, but most grazes heal without any trace whatever.

Contusions also heal completely since the wound consists mainly of blood seeping into the tissues. This blood is broken down and absorbed by the body, so bruises gradually soften and disappear. Since the structures in the bruised area are not damaged, no scarring results.

Other types of wound heal by scarring. When the injury occurs, there is a gap in the tissue which becomes filled with blood. This blood becomes clotted, and soon after, the blood clot is invaded by cells called fibroblasts. These cells lay down a simple type of fibrous tissue which helps to tie the sides of the wound together. At the same time the fibrous tissue is penetrated by small blood vessels from the surrounding tissues. This blood supply brings with it more fibre-producing cells as well as a good supply of raw materials: oxygen, protein, sugar and so on. The healing wound is a very busy area at this early stage of healing, and this is shown by the fact that a healing wound is slightly swollen and firm, and the scar is a bright red to pink. Over the next few months the early fibrous tissue becomes more highly organized, with the protein fibres lined up to resist the stresses in the wound. The scar becomes more 'mature' and is seen to become softer and whiter. In some areas scars become almost invisible and blend in very well with the surrounding tissue a good example is a scar on the palm of the hand. In other areas such as the abdomen and chest, the scar tends to widen as it heals, leaving a permanent, obvious scar.

In relatively simple tissues such as skin or fat, a small scar has little or no effect. In more specialized tissues scarring may stop their function altogether. For example, if a nerve is cut the impulses passing from the brain along the nerve can be stitched back together, but if the cut area fills with scar tissue the nerve will still not work. Special techniques for repairing nerves can minimize this problem.

TREATMENT

Nature is a great healer of wounds. Any treatment given does not affect this healing process, but it sets the stage for healing without complications and with a minimum of side-effects.

ABRASIONS

These generally heal quickly and completely. The only treatment required is cleaning of the wound followed in some cases by a dressing. Cleaning is best done with a mild soap and water - cold water is more soothing. Ideally the graze should then be left exposed to the air. Within a few hours a tough scab forms over it, acting as a natural protective dressing. In practice it may be better to cover the graze with a dressing to prevent it from rubbing on clothing or becoming dirty. Plastic materials tend to keep the graze moist and dark, favouring infection, so a material which 'breathes' is better.

CONTUSIONS

These require little attention. The application of a cold compress or ice pack as soon as possible a r the injury helps to prevent swelling, and this may be very worthwhile in, for example, a black eye. Bruises resolve at their own speed and there is little that can be done to hasten this process.

GUN SHOT WOUNDS

Treatment consists of early surgery to explore the path of the bullet. All tissue that has been so badly damaged that it cannot survive must be removed at this first operation. It is often necessary to remove large amounts of tissue, or even to amputate a limb, to achieve a clean wound. Major bleeding must be stopped, and damaged vessels repaired to ensure a blood supply to the surrounding tissues. Damaged bowel must be removed to prevent leakage and serious infection, and broken bones must be cleaned, splintered or put in traction.

Complicated surgery to reconstruct damaged tissue is left to a later operation - this first operation is performed to save life and to set the stage for a clean, healthy wound.

Techniques of treating gunshot wounds have improved greatly in recent years, so that most people who reach a hospital alive now survive and recover.

LACERATIONS

Lacerations often need treatment. Bleeding is best controlled by direct pressure over the cut, using clean gauze or cloth. Elevation of the lacerated part also helps to reduce bleeding. Firm pressure applied for several minutes generally stops bleeding from small vessels. If a larger vessel is cut, continuous pressure may be necessary until the victim reaches hospital. Even if a large artery is cut it is better to apply the pressure directly to the wound rather than to use a tourniquet. This is because a tourniquet can do serious damage both in the tissues which are being squeezed and in the rest of the limb which is having its blood supply stopped.

Because all tissues have a certain degree of stretchiness, any cut tends to retract' or become larger. For example, a straight cut of 15 cm (6 in) to the skin becomes a 15 cm by 2.5 cm (6 in by 1 in) wide wound. This is why many lacerations need to be stitched together to allow the cut edges to heal in the shortest time and with the smallest scar. The stitches need to be left in place for a long enough time for healing to make the wound strong enough to hold itself together. In a wound which has merely gone through the skin, only the skin itself is stitched. In deeper wounds several layers of tissue may be divided, and each layer is stitched separately.

There are two main types of stitches: absorbable and non-absorbable. Absorbable stitches are made of materials which slowly dissolve and are removed by the body; the commonest is 'catgut' which is in fact made of sheep's intestines. Non absorbable sutures are made of silk, nylon or steel. The type of suture which is used depends on the judgement of the doctor. AS a general rule, non-absorbable sutures are stronger and are less likely to react in the tissues, while absorbable sutures are convenient in that they don't need to he removed.

Dressings for lacerations may be the only treatment needed or they may be used after stitching. A firm dressing will help to stop bleeding and make the wound more comfortable. Adhesive strips may be used instead of stitches to pull the wound together. But in general, dressings are used simply as a protection against rubbing or knocking the wound while it is healing. There are many types of dressing materials, but none has any magical effect on wound healing; often leaving the wound open to the fresh air is as good a treatment as any.

PUNCTURE

A puncture wound needs treatment if the puncturing object is large or dirty. Because the wound is deep it is easy to underestimate the amount of damage just by looking at the surface. It may be necessary for the track of the puncture to be opened by means of an operation and any damage tissue cleaned and repaired.

COMPLICATIONS

Whenever the skin is broken, bacteria enter the wound from outside. Whether these bacteria actually cause an infection depends on their strength and number and on the ability of the tissues to resist the bacteria. Of these two factors the most important is the 'resistance'. For example, a young healthy person who gets a cut on a fingertip rarely gets an infection in the wound; the tissues have a good blood supply and the individual's defences take care of any bacteria which get into the cut.

If a wound contains a lot of badly damaged tissue, infection is much more likely to occur. The damaged tissue will have a poor blood supply so the body's cells may have difficulty in reaching the area where infection is beginning. The bacteria actually feed and multiply on the dead tissue, and as they multiply they will begin to break down and destroy previously normal tissue.

Symptoms of a wound infection take 24 to 48 hours to develop after the injury. The victim notices increasing pain in the wound as the infection causes swelling and tightness in the tissues. The pain becomes constant and throbbing, while the wound itself swells and becomes red and hot. Later, fluid may begin to escape from the wound - clear fluid at first but later it may become pus. The victim will feel unwell and may have a fever.

The best treatment of an infected wound is prevention. Any wound should be thoroughly cleaned. Superficial wounds need only be washed with mild soap or an antiseptic. Deeper wounds should be examined by a doctor. If there is dirt ground into the tissues or if there is a lot of bruised, crushed tissue, all this will need to be removed, leaving clean healthy tissue. Where there are very dirty wounds, antibiotics may be given.

In established wound infections the wound must be opened up so that any fluid or pus can drain away and the dead and damaged tissue can be removed. If the wound has previously been sutured, the stitches are generally removed. It may be helpful to elevate the infected area as this helps to get rid of the swelling. Antibiotics should be taken until the wound is well settled - a minimum of five days.

One particular type of infection which must be guarded against is 'lockjaw' or tetanus. The tetanus bacteria give off tiny spores which are very hardy and live in soil and animal excrement. If the spores become established in a wound they give off toxins which attack the nervous system, causing severe muscle spasms. Muscle spasms attacking the jaw muscles cause a forcible biting action, hence the term lockjaw. Once t is con it] n starts, treatment is difficult and many victims die. Lockjaw is prevented by cleaning wounds thoroughly and giving vaccine against tetanus. Most people receive the vaccine as children, and booster doses are needed every five years to maintain resistance; in practice most people receive a booster when they actually suffer a wound rather than being vaccinated regularly.

Another complication is foreign bodies. This includes any piece of foreign material which is left behind in a wound. Foreign bodies cause two problems: they may press on important structures causing pain and damage, and they cause inflammation in the tissues. The cells of the body are able to recognize when a piece of foreign material is present, and then try to get rid of the 'intruder'. This process results in inflammation which continues until the foreign body is removed. Some foreign material is 'inert' - that is, it does not cause much of this type of reaction. Stainless steel and glass can remain in the body for years with little or no reaction. Biological materials such as cloth or wood cause very intense reactions and must be removed for this reason.

It is common belief that foreign bodies such as needles move around in the body and may end up lodged in a vital organ. In fact this does not happen. A needle or a piece of glass in the hand or foot usually needs to be removed because it hurts when standing or gripping, but the same foreign body in a large muscle such as the thigh is best left alone as it will never cause any harm. There are many war veterans who have shrapnel embedded in various parts of their bodies for decades, without suffering any ill effects.

It is important to remove foreign bodies if infection is present, as they tend to maintain an infection despite treatment, thus impeding wound healing.

FIRST AID

FIRST AID IN MULTIPLE INJURIES

Look for signs of breathing. Make sure the mouth and throat are clear - there may be false teeth, chewing gum or blood blocking the throat. If breathing has stopped, begin mouth-to-mouth resuscitation

If the victim is unconscious, roll him gently onto his side. This position helps to keep the breathing tubes clear.

Control areas of bleeding by direct pressure on each wound. This may require several pairs of hands, each person concentrating on one wound.

Keep the victim warm but not hot.

Support any obvious fractures with splints, cushions or blankets.