01-4 Trauma: Extremities, Burns, Bites, Misc Flashcards
I. A 25-year-old man is shot with a .22-caliber revolver. The entrance wound is in the anteriolateral aspect of his thigh, and the bullet is seen by x-rays to be embedded in the muscles, posterolateral to the femur.
Apart from the obvious need to fix a bone that might have been shattered by a bullet, the issue in low-velocity gunshot wounds (or stab wounds) of the extremities is the possibility of injury to major vessels. In the first vignette, the anatomy precludes that possibility. Thus that patient only needs cleaning of the wound and tetanus prophylaxis. The bullet can be left where it is.
II. A 25-year-old man is shot with a .22-caliber revolver. The entrance wound is in the anteromedial aspect of his upper thigh, and the exit wound is in the posterolateral aspect of the thigh. He has normal pulses in the leg, and no hematoma at the entrance site. X-rays show the femur to be intact.
In the second patient, the anatomy of the area makes vascular injury very likely, and lack of symptoms does not exclude that possibility. At one time, all of these would have been surgically explored. Arteriogram then became the preferred diagnostic modality, and, currently, Doppler studies or CT angio offer non-invasive alternatives.
III. A 25-year-old man is shot with a .22-caliber revolver. The entrance wound is in the anteromedial aspect of his upper thigh, and the exit wound is in the posterolateral aspect of the thigh. He has a large, expanding hematoma in the upper, inner thigh. The bone is intact.
In the third example, it is clinically obvious that there is a vascular injury. Surgical exploration is in order. Arteriogram preceding surgical exploration is done only in parts of the body where the very specific site of the vascular injury dictates the use of a particular incision versus another (for instance at the base of the neck and thoracic outlet).
A young man is shot through the arm with a .38-caliber revolver. The path of the bullet goes right across the extremity, from medial to lateral sides. He has a large hematoma in the inner aspect of the arm, no distal pulses, radial nerve palsy, and a shattered humerus.
That he will need surgery is clear, but the issue here is what to do first. A very delicate vascular repair, and an even more fragile nerve reanastomosis, would be at risk of disruption when the orthopedic surgeons start manipulating, hammering, and screwing the bone. Thus the usual sequence begins with fracture stabilization, then vascular repair (both artery and vein if possible), and last nerve repair. The unavoidable delay in restoring circulation will make a fasciotomy mandatory.
In a hunting accident, a young man is shot in the leg with a high-powered, big-game hunting rifle. He has an entrance wound in the upper outer thigh that is 1 cm in diameter, and an exit wound in the posteromedial aspect of the thigh that is 8 cm in diameter. The femur is shattered.
Even though the major vessels are not in the path of this bullet, this young man will need to go to the operating room to have extensive debridement of the injured tissues. High-velocity bullets (military weapons and big-game hunting rifles) produce a cone of destruction.
A 6-year-old girl has her hand, forearm, and lower part of the arm crushed in a car accident. The entire upper extremity looks bruised and battered, although pulses are normal and the bones are not broken.
In addition to possible hyperkalemia, crushing injuries lead to two concerns; the myoglobinemia– myoglobinuria–acute renal failure issue, and the delayed swelling that may lead to a compartment syndrome. For the first, plenty of fluids, osmotic diuretics (mannitol), and alkalinization of the urine help protect the kidney. For the latter, fasciotomy is the answer.
You get a phone call from a frantic mother. Her 7-year-old girl spilled Drano all over her arms and legs. You can hear the girl screaming in pain in the background.
Management. The point of this question is that chemical injuries—particularly alkalis—need copious, immediate, profuse irrigation. Instruct the mother to do so right at home with tap water, for at least 30 minutes before rushing the girl to the ER. Do not pick an option where you would be “playing chemist,” i.e., soak an alkaline burn with an acid or vice versa.
While trying to hook up illegally to cable TV, an unfortunate man comes in contact with a high-tension electrical power line. He has an entrance burn wound in the upper outer thigh, and an exit burn lower on the same side.
Management. The issue here is that electrical burns are always much bigger than they appear to be. There is deep tissue destruction. The patient will require extensive surgical debridement, but there is also another item (more likely to be the point of the question): myoglobinemia, leading to myoglobinuria and to renal failure. Patient needs lots of IV fluids, diuretics (osmotic if given that choice, i.e., mannitol), perhaps alkalinization of the urine.
If asked about other injuries to rule out, they include posterior dislocation of the shoulder and compression fractures of vertebral bodies (from the violent muscle contractions), and late development of cataracts and demyelinization syndromes.
A man is rescued by firemen from a burning building. On admission it is noted that he has burns around the mouth and nose, and the inside of his mouth and throat look like the inside of a chimney.
What is it? There are two issues here: carbon monoxide poisoning and respiratory burns, i.e., smoke inhalation producing a chemical burn of the tracheobronchial tree. Both will happen with flame burns in an enclosed space. The burns in the face are an additional clue that most
patients will not have.
For the first issue we determine blood levels of carboxyhemoglobin, and put the patient on 100% oxygen (oxygen therapy will shorten the half-life of carboxyhemoglobin). For the second issue, diagnosis can be made with bronchoscopy, but the actual degree of damage—and the need for supportive therapy—is more likely to be revealed by monitoring of blood gases.
Management. Revolves around respiratory support, with intubation and use of a respirator, if needed.
A patient has suffered third-degree burns to both of his arms when his shirt caught on fire while lighting the backyard barbecue. The burned areas are dry, white, leathery, anesthetic, and circumferential all around arms and forearms.
What is it? You are meant to recognize the problem posed by circumferential burns: the leathery eschar will not expand, while the area under the burn will develop massive edema, thus circulation will be cut off. (Or in the case of circumferential burns of the chest, breathing will be compromised.) Note that if the fire was in the open space of the backyard, respiratory burn is not an issue.
Management. Compulsive monitoring of Doppler signals of the peripheral pulses and capillary filling. Escharotomies at the bedside at the first sign of compromised circulation. In deeper burns, fasciotomy may also be needed.
A toddler is brought to the ER with burns on both of his buttocks. The areas are moist, have blisters, and are exquisitely painful to touch. The story is that the kid accidentally pulled a pot of boiling water over himself.
What is it? Burns, of course. There are several issues. First, how deep. The description is classic for second-degree burns. (Note that in kids third-degree burn is deep bright red, rather than white leathery as in the adult.) How did it really happen? Scalding burns in kids always brings
up the possibility of child abuse, particularly if they have the distribution that you would expect if you grabbed the kid by the arms and legs and dunked him in a pot of boiling water.
Management. For the burn is Silvadene (silver sulfadiazine) cream. Management for the kid requires reporting to authorities for child abuse.
An adult man who weighs x kilograms sustains second- and third-degree burns over—whatever. The burns will be depicted in a front-and-back drawing, indicating what is second-degree (moist, blisters, painful) and what is third-degree (white, leathery, anesthetic). The question will be about fluid resuscitation.
The first order of business will be to figure out the percentage of body surface burned. The rule of nines is used. In the adult, the head is 9% of body surface, each arm is 9%, each leg has two 9%s, and the trunk has four 9%s.
An adult who weighs x kilograms has third-degree burns over… (the calculated surface turns out to be more than 20%). Fluid administration should be started at a rate of what?
If you are simply asked how fast should the infusion start, rather than what is the calculated total for the whole day, the answer is Ringer lactate (without sugar) at 1,000 ml/h.
An adult man who weighs x kilograms has third-degree burns over… (a set of drawings provides the area). How much is the estimated amount of fluid that will be needed for resuscitation?
If asked this way, we need to remember the old Parkland formula: 4 ml of Ringer lactate (without sugar) per kilogram of body weight, per percentage of burned area (up to 50%) “for the burn,” plus about 2L of 5% dextrose in water (D5W) for maintenance. Give one half in the first
8 hours, the second half in the next 16 hours. The second day requires about one half of that calculated amount, and is the time when colloids should be given if one elects to use them. By the third day there should be a brisk diuresis, and no need for further fluid. Remember that these amounts are only a guess, to be fine-tuned by the actual response of the patient (primarily hourly urinary output). Higher amounts are needed in patients who have respiratory burn, electrical burns, or recent escharotomies. The use of the formulas is now less frequently done, since physicians typically end up adjusting the rate of fluid administration on the basis of the urinary output after initial resuscitation.
After suitable calculations have been made, a 70-kg adult with extensive third degree burns is receiving Ringer lactate at the calculated rate. In the first 3 hours his urinary output is 15, 22, and 18 ml.
Most experts aim for an hourly urinary output of at least 0.5 ml/kg, or preferably 1 ml/kg body weight per hour. For patients with electrical burns the flow should be even higher (1 to 2 ml/kg per hour); thus by any criteria this fellow needs more fluid.
