Soft-Tissue Trauma

Skin & soft-tissue basics

The soft tissues of the body are the skin, the fat, the muscle, the blood vessels, the connective tissue, the membranes, the glands and the nerves. The skin is the largest of them, and it does more than cover what lies beneath. It protects the deeper tissues, it maintains the body's water balance, it regulates temperature, it excretes waste, and it absorbs shock.

Skin is built in 3 layers, and how deep a wound reaches is much of what determines how serious it is. The outermost layer is the epidermis, which contains no blood vessels and no nerves. Beneath it lies the dermis, the layer that holds the vessels, the nerves and the glands; once the dermis has been opened, the wound carries a major risk of infection and of bleeding. Deepest is the subcutaneous layer, which is largely fat and which insulates the body and absorbs shock.

Closed wounds

In a closed wound the skin is not broken and the damage is entirely beneath the surface. The table below sets out the three kinds of closed wound and what distinguishes each one.

Table 30.1Closed wounds

Care follows one pattern whatever the type. Begin with the ABCs and oxygen (O2). If the mechanism suggests bleeding inside the body, treat the patient for internal bleeding and shock. Splint painful or deformed extremities, monitor for shock to develop, and transport promptly.

Open wounds

An open wound is one in which the surface of the skin is broken, so that blood can leave the body and contamination can enter it. The table below describes the open wounds you will meet and the point that matters most about each.

Table 30.2Open wounds

Explosions produce a pattern of injury of their own, and blast injuries are described by 4 mechanisms. The primary mechanism is the pressure wave itself, which damages organs. The secondary mechanism is shrapnel driven into the patient. The tertiary mechanism is the patient being thrown by the force of the blast. The quaternary mechanism covers the rest of what an explosion does, such as chemical exposure and burns.

High-pressure injection injuries deserve particular suspicion, because they look minor on the surface and are devastating internally. Elevate and splint the limb, never apply cold, and persuade the patient to accept transport even if there is no pain at all.

General open wound care & special situations

Care of an open wound runs in a set order. Expose the wound, then clean the surface only; controlling the bleeding takes priority over cleaning. Use direct pressure; if the bleeding from an extremity is life-threatening — spurting, pulsing with the heartbeat, or pooling fast — apply a tourniquet straight away rather than working up to it. Elevation is no longer part of bleeding control: it delays the pressure that actually works and has never been shown to stop bleeding on its own. Treat for shock and give O2, cover the wound with a sterile dressing, and hold the dressing in place with a bandage, checking the distal pulse once the bandage is on.

Three situations call for something beyond that sequence. An impaled object is never removed in the field; stabilize it where it lies with bulky dressings packed against both sides of it. With an avulsion or an amputation, save the separated part: wrap it in a sterile dressing moistened with saline and keep it cool, never placing it directly on ice and never immersing it in water, since the avulsed tissue has lost its oxygen supply and will die.

Genital injuries bleed heavily, because the tissue is highly vascular. Control the bleeding, keep the patient's dignity and privacy in mind throughout, and consider the possibility of sexual abuse or assault, particularly in a child.

Classifying burns by depth

Burns are classified first by depth, which is to say by how far through the skin the heat has destroyed tissue. The table below gives the three depths, the layers each one involves and what each looks like on the patient.

Table 30.3Classifying burns by depth

Depth alone does not describe a burn; you also need its extent, expressed as a percentage of the body surface area. The Rule of Nines divides the adult body into regions of 9%: the head and neck, each arm, the chest, the abdomen, the upper back, and the lower back with the buttocks are 9% each, and so are the front and the back of each leg. The genitals account for the remaining 1%. A child's proportions are different, and only two regions change: the head and neck take 18% rather than 9%, and each leg takes 13.5% rather than 18%. Everything else is counted as it is in an adult, so each arm is still 9%, the chest and abdomen together and the entire back are 18% each, and the genitals are 1%. A child's head takes a larger share of the body surface and the legs a smaller one, which is why a burn of the same size is a bigger burn in a child.

Burn center criteria & thermal burn care

Some burned patients need a burn center rather than the nearest emergency department. Transport to a burn center is indicated for:

• Partial-thickness (2nd-degree) burns covering more than 10% of the body surface area (BSA).
• Burns of the face, the genitalia, the hands, the feet or a major joint.
• Any full-thickness (3rd-degree) burn.
• Electrical burns.
• Inhalation burns.
• Burns accompanied by other trauma.
• Patients with special needs.

Care of a thermal burn begins by stopping the burning process. Turn next to the airway and breathing, looking for a hoarse voice, stridor, soot and singed nasal hair, any of which points toward an inhalation injury, and then complete the primary assessment. Treat for shock and give O2, classify the burn by depth and extent, and cover it with a dry sterile dressing.

Never put ointments, sprays or butter on a burn, never break blisters, and never apply ice. A cool wet dressing is appropriate only for a small isolated burn; used over more than 10% of the body surface area it risks hypothermia. Immersion and scald burns raise the possibility of abuse, especially in children.

Chemical, electrical & radiation burns

A chemical burn goes on burning as long as the chemical remains on the patient. Brush a dry chemical off first, then flush with copious flowing water for at least 20 minutes and keep flushing en route. The two families of chemicals behave differently. Acids coagulate the tissue they touch, which tends to limit their own penetration; the exception is hydrofluoric acid, which penetrates deeply while showing minimal signs on the surface. Alkalis liquefy tissue, so they reach deeper and need longer irrigation.

At an electrical injury, assume the source is still live unless it has been confirmed off. The signs to look for are entry and exit burns, paralysis, dysrhythmia or cardiac arrest, and seizures. Manage the airway and breathing with the risk of swelling in mind, have basic life support (BLS) and the automated external defibrillator (AED) ready, take spine precautions, and search for at least 2 burn sites rather than stopping at the first one you find. Cover the burns with dry sterile dressings and transport promptly, since cardiac problems can appear after a delay.

Radiation produces both an immediate and a delayed injury: burns at the time of exposure, and radiation sickness later. Do not approach a radiation incident without the proper protection and training.

Dressing & bandaging principles

A dressing is the sterile material placed over the wound itself; a bandage is what holds the dressing in place, and it does not need to be sterile. A bandage is applied neither too tightly nor too loosely, and no loose ends are left hanging. Leave the fingers and toes exposed so that you can keep watching circulation, the one exception being digits that are themselves burned. Wrap from the distal end of the limb toward the proximal end.