The skin, also known as the integument, is the largest organ in the body and is composed of 2 distinct layers: the epidermis (outermost layer) and the dermis (inner layer). The integument serves several important functions.
The skin serves 4 functions:
The epidermis is primarily responsible for preventing water loss and protecting the body from the external environment and mechanical forces. The innermost portion of this layer is made of living cells that begin at the base of the layer and push outward toward the surface. As these cells move outward, they become filled with a protein called keratin and die. They are then known as the stratum corneum, which makes up the tough, outer layer of skin. The epidermis also contains sporadically placed melanocytes that are responsible for the production of melanin. A person with more melanocytes will have a darker skin.
The dermis lies immediately underneath the epidermis and is made up of tough elastic fibers called collagen and elastin. These work together to make the skin resistant to tearing and distortion. Also within the dermis lie the capillaries responsible for thermoregulation. White blood cells called macrophages and lymphocytes are located throughout the dermis as well and serve as a first-line defense against any pathogens that may get across the skin or as a result of cuts or abrasions. The following structures also lie within the dermis:
A layer largely consisting of fat (adipose) cells that provides insulation and cushioning, subcutaneous tissue underlies the dermis and is superficial to the major muscle groups. The subcutaneous tissue also is highly vascular.
Hemorrhage can be either internal or external, but either can be severe enough to lead to hypovolemic, specifically hemorrhagic, shock. Humans contain between 65 and 70 mL/kg of circulating blood at any time, which correlates to approximately 5 L of blood in an average-sized adult. The loss of just 1 L of blood in an adult, whether internally or externally, will lead to vital sign changes and the onset of signs of shock. To broaden this number, the body cannot tolerate a loss of more than 20% of the circulating volume. The type of vessel lacerated will determine how quickly the body will lose blood and what the bleeding looks like if the bleeding is external.
Under normal circumstances, minor bleeding will clot off and stop in about 10 minutes. The following conditions or situations will interfere with normal clotting processes.
Closed wounds are widely varied in severity and can lead to life-threatening blood loss. The following are examples of closed wounds or internal hemorrhages, complete with symptoms and prehospital treatment.
Contusions. Commonly known as bruises, contusions involve breaks in the capillary vessels underneath the skin, without actually breaking the skin. These generally are not life threatening, and little prehospital treatment is required.
Hematomas. Larger subcutaneous vessels and sometimes arteries can be ruptured and bleed more heavily than the capillary vessels in contusions. This results in a raised, blood-filled area resembling a large blister. This bleeding can continue to the point where pressure builds up and underlying tissues are deprived of blood and therefore O2. This can result in necrosis to the area. Although not life threatening, untreated hematomas can lead to significant tissue damage. The paramedic should apply ice or a cold pack to the area if possible. Also, mark the edges with a pen so that later assessments will clearly reveal whether the hematoma is still growing. Definitive treatment is sterile drainage at the hospital.
Within all 4 limbs, individual muscle groups are surrounded by a tough covering called fascia, which confines the muscles to a finite compartment. Bleeding or swelling that occurs within this compartment raises the pressure within the compartment. Compartment syndrome results when the pressure within the compartment rises too high and circulation to the muscle within the compartment is compromised. If this is allowed to continue for an extended period of time, irreversible tissue death (necrosis) can set in. This can happen with soft-tissue injuries or fractures to the limb.
Symptoms of compartment syndrome include the 6 Ps:
Prehospital treatment for compartment syndrome is limited to rapid transport and delivery of the patient to the emergency department before the extremity is pulseless. Narcotic pain relief may be attempted, but it is usually unsuccessful at relieving pain. Splinting the extremity to prevent further injury is recommended; however, it is critically important to make sure that there are pulses after splinting if they existed before splinting. Applying the splint too tight can increase the possibility of compartment syndrome. The administration of high-flow O2 will maximize the amount of O2 the tissue is receiving. Providing intravenous crystalloid fluid also will maximize the flushing of toxins resulting from rhabdomyolysis.
Internal bleeding from injury to internal organs can be difficult to find or assess. If the patient has sustained abdominal or chest injuries, presume that there is internal bleeding. This maintains a high index of suspicion so that the patient will receive a higher level of care. If the abdomen is firm to palpation or if there is any bruising over either flank (the Grey Turner sign) or around the umbilicus (the Cullen sign), there may be internal bleeding. Rebound tenderness is a sign of peritoneal irritation, which could be from blood in the perineum or other toxins from ruptured bowels.
Hemorrhage should be suspected and transport initiated to a trauma center for emergency surgery. Initiate cardiac monitoring and an intravenous line. Consider a 200–500 mL bolus or run the intravenous line wide open if the patient is already showing signs of shock.
Open wounds bleed externally, so the amount of blood lost often is visible. This means that it is much more likely to accurately estimate the amount of blood lost, making it easier to anticipate the onset of shock. Open wounds have a greater capacity to bleed than internal wounds, which often can be self-limiting because of the confined space in which to bleed.
With open wounds, however, there is a greater likelihood of contamination of the wound with bacteria and other debris. Although this does not necessarily pose an acute threat to the patient, in an isolated open wound, such as an abrasion sustained from a low-speed fall from a pedal bicycle, the wound should be irrigated with sterile water before placing the bandage. Deeper wounds and burns may require more aggressive debridement at the hospital.
Abrasions are very shallow wounds that occur when the skin is dragged across a rough surface. This will essentially remove parts of the epidermis, exposing the nerve endings found in the dermis to air. This is what causes the most pain. Rinsing the abrasion may cause the patient more pain in the short term, but it may be better for the patient to help minimize the chances of infection. Cover lightly with a bandage.
An amputation is the partial or complete separation of a digit or limb from the patient. In a partial amputations, the limb remains attached to the person only via an isthmus of skin. In complete amputations, the limb is completely detached. Bleeding in an amputation often is less than anticipated because the vessels are able to constrict. The paramedic should be cautious about jagged, exposed bone ends that could catch on something or cause a laceration to the rescuers.
A unique amputation is the degloving injury. In this injury pattern, the bones are usually left intact, with only the skin removed from the body—the way one would remove a glove or a sock. Often times, the skin is removed overall intact, but the appearance is particularly gruesome. This, and any shredding or tearing full amputation, often will have excessive bleeding because the vessels were not cut cleanly transverse.
Treatment for an amputation begins with cleaning the remaining part of any debris. Wrap the stump with sterile roller gauze. In the unlikely event that the bleeding is profuse, immediately consider a tourniquet placed on the proximal limb. For the amputated part, rinse it with saline and wrap loosely with gauze soaked in sterile water or saline. Place the part in a plastic bag and seal the bag. Place the bag inside a cooler with cold packs or ice but do not let the part or any portion of the part freeze. The part should not be submerged in water and should not be in direct contact with the ice. Transport the patient immediately, whether or not the part can be located.
An avulsion occurs when a flap of skin is torn loose, either partially or completely. In a partial avulsion, the skin flap is still attached to the patient; in a complete avulsion, the chunk of skin is completely removed, almost like removing a piece of cheese from a block of cheese with a cheese slicer.
Bleeding with an avulsion is dependent on its location. An avulsion of the scalp or facial skin may bleed profusely, whereas an avulsion of the back or dorsal forearm, for example, may ooze only. Begin treatment for an avulsion by washing the area where the flap was removed with sterile water. Return the flap to its original anatomic position. If it was a complete avulsion, give the best approximation of its original location. Cover the wound with a dry sterile dressing. If available, apply a cold pack to extend the time that the flap of skin will remain viable.
Human and animal bites, though often minor soft-tissue injuries, expose the patient to a wide variety of infections. The human mouth contains far more strains of bacteria that can cause infection than either the dog or cat. Wild animals can have any number of bacteria in their mouths and also may have the virus that causes rabies. Any bite, especially human, where the skin is broken should be seen at a hospital.
Treatment for bites with broken skin should include the following:
When an extremity is crushed under a considerable weight, such as a car that fell off a jack or during a building collapse, extensive damage to the body can occur the longer the body is under the weight. The crush weight alone can splinter bones and rupture muscles. A person can recover from these injuries if the weight can be removed relatively quickly. If the crushing object is in place for more than 4 hours, however, crush syndrome develops, especially when arterial blood flow compromised.
Primarily, crush syndrome results in tissue necrosis to the area under or distal to the crushing object. This results in rhabdomyolysis in all the muscles in this region because of the lack of circulation. Rhabdomyolysis is the breakdown of skeletal muscle, which releases myoglobin into the bloodstream. The myoglobin can cause ARF if not treated aggressively. In addition to rhabdomyolysis, all cells, including the muscle cells in the area, release into the bloodstream waste products of metabolism. These waste products include acids from anaerobic respiration, CO2, urea, and potassium from both cellular death and metabolism. This combines for an isolated area of metabolic acidosis. Clots also can form throughout the extremity because of hemostasis.
As a result of all this developing while the crushing object is in place, the level of toxins in the crushed extremities can reach lethal quantities in 4 hours depending on the extent of the area crushed. Therefore, removal of the object without first initiating medical treatment could result in almost immediate patient death from cardiac arrest. After ensuring scene safety and accessing the patient, conduct as much of the primary survey as possible and address any threats of the ABCs. At this point, it is important to monitor the patient while coordinating efforts to remove the crushing object from the patient. Take the following steps just prior to removal of the crushing object.
Mannitol can be used to accelerate diuresis. Lasix should not be used because it can add to the acid present in the blood. If medications are not an option, apply a tourniquet proximal to the crush if possible. Consult medical command before readministering of the medications and for assistance in establishing the intravenous fluid flow rate.
Lacerations are cuts that often extend deep into the dermis and sometimes beyond. The severity of the laceration will depend on the structures that were damaged from the laceration. An incision is a special kind of laceration, where the edges are very precise and the cut was made intentionally, generally with a surgeon’s scalpel. Apply direct pressure and elevation and move quickly to a tourniquet if arterial bleeding is noted or if the bleeding does not stop with direct pressure and elevation.
Any instrument that penetrates the skin and underlying structures is a puncture wound. This can be from a knife, a nail, or a shard of wood kicked up by a saw blade. With puncture wounds, always assume that it is deeper than can be assessed and that more than just skin and subcutaneous tissue are involved. The penetrating objects also can deliver bacteria and debris deep into the body, so infection is a common complication. Shock can develop quickly, from blood loss or damage to fluid-filled, hollow organs, such as a bladder or the GI tract.
If the penetrating object has been removed prior to EMS arrival, treatment is much the same as that for a laceration: Clean with sterile water or saline and bandage.
A more unique situation presents when the penetrating object has been left in the patient. This is now called an impaled object and should not be removed; the object may be tamponading internal bleeding. The only reasons to manipulate an impaled object would be if its presence is too cumbersome to get the patient into the ambulance or if the object is attached to something else, such as a fencepost or car antenna. At any rate, motion of the object itself or of the patient around the object should be limited to minimize the chances of causing or worsening internal bleeding.
Treatment of the impaled object is more complicated than a laceration or an open puncture wound. First, minimize movement of the soft tissues immediately surrounding the impaled object because this could further damage those structures. Apply bulky padding around the impaled object so that its motion is limited. Bulky dressings can include rolls of gauze or blankets and towels, depending on the size of the impaled object. The only time an impaled object should be removed is if it interferes with the airway or the performance of CPR. Removal of an object impaled through the facial cheek is acceptable because it may interfere with the airway, and the paramedic can provide direct pressure to both sides of the wound, minimizing bleeding.
Hemostatic agents are chemicals that are introduced into a wound that has bleeding that is not able to be stopped with direct pressure and is usually in an area where a tourniquet cannot be placed. They come as a powder or embedded in specialized dressings. The chemicals absorb the water from the blood and activate the clotting cascade. These were designed for the military and are not typically recommended in areas where transport times are short.
The only definitive care for internal bleeding is generally surgery. The best treatment a paramedic can do for a patient in the field is to recognize that the patient is, in fact, bleeding internally or maintain a high index of suspicion that the patient could have internal injuries and rapidly transport the patient to the hospital. During transport, the patient should receive at least 1, preferably 2, large-bore intravenous lines with fluids running wide open. Although this will maintain blood pressure, it will not replace the O2-carrying power of blood, so even this will eventually become insufficient.