A 28-year-old white male who was the restrained front passenger of a vehicle traveling in excess of 60 mph is brought to the ED via ambulance. The driver of the vehicle was found dead at the scene. Ambulance personnel report it took 5–10 minutes to extricate the patient. On arrival, he is mumbling incoherently. He is initially able to give his name, but he is slurring his words. He denies any medical problems, medications, or allergies. Vitals signs include temperature of 35.5°C, pulse 148, respirations 35, blood pressure of 65/30, and oxygen saturation of 81% on 100% oxygen by face mask. On exam, he is in severe respiratory distress. Lung sounds are absent on the right and diminished on the left. Heart sounds are muffled. You determine that this patient needs immediate treatment for a pneumothorax.
Which of the following is most appropriate at this time?
- A) Perform needle decompression on the left.
- B) Perform needle decompression on the right.
- C) Place a chest tube on the left.
- D) Place a chest tube on the right.
- E) Perform a chest radiograph and act on the basis of the results.
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Answer: B Discussion The correct answer is B. The combination of hypotension, hypoxia, and absent breath sounds suggests a tension pneumothorax. Immediate decompression of the affected hemithorax should be performed by placing a large-bore (14- or 16-gauge) needle through the chest wall to relieve intrathoracic pressure. Traditionally this was accomplished by placing a needle in the second intercostal space at the midclavicular line. However, due to high risk of mediastinal vascular injuries, current practices recommend placing the needle in the traditional location for chest tube—that, is the fifth or sixth intercostal spaces at the midaxillary line. Of particular note is answer E. Tension pneumothorax should never be diagnosed on a chest radiograph. It is a true emergency that requires treatment on the basis of clinical exam.
Following needle decompression, your patient’s vital signs are now improved: pulse 122, respirations 28, blood pressure 88/40, and oxygen saturation of 92% on 100% oxygen by face mask. Due to the extent of injuries and continued respiratory difficulties, you intubate the patient. In proceeding with your “ABC” evaluation, you consider the patient’s circulatory status. You estimate that he weighs about 70 kg.
Assuming that there is no further fluid loss, what is the APPROPRIATE fluid resuscitation to return his vascular volume to normal?
- A) 1,500 cc.
- B) 3,000 cc.
- C) 4,500 cc.
- D) 6,000 cc.
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Answer: C Discussion The correct answer is C. What follows is a way to estimate the patient’s fluid loss—of interest to test-writers but of less interest in the ED. Each 10% of volume lost is equivalent to 500 cc of intravascular volume depletion in a 70 kg male. A 10% volume loss will result in no changes in vital signs. A 20% volume loss results in isolated tachycardia. At 30% volume loss, there is hypotension, tachycardia, possibly altered mentation, and peripheral vasoconstriction resulting in hypothermia. At 50% volume loss, there is marked hypotension, tachycardia, altered mentation, and vasoconstriction. Given this patient’s exam, you can estimate a loss of 30% of his intravascular volume for a total of 1,500 cc of estimated loss (average intravascular volume in 70 kg man = 5,000 cc, thus a 30% volume loss =1,500 cc). Then you must remember that intravascular volume will redistribute to the extravascular space, so fluids should be replaced at a 3:1 ratio. In this case, correct fluid administration for an estimated 30% fluid loss would be 4,500 cc. Use crystalloid solution (normal saline or Ringer’s lactate) via 2 large-bore IV catheters. Note, however, that once a patient has not responded to 2 liters of crystalloid, blood may be necessary.
Following improvement in his vital signs, the patient is placed in external fixation device for femur fracture. Operating room fixation is deferred secondary to instability of the patient’s medical status. He is admitted to the intensive care unit on a respirator with Ccollar following negative FAST examination (Focused Assessment with Sonography for Trauma, a sonographic evaluation to rule out fluid in perihepatic, perisplenic, pelvic, and pericardial spaces). Repeat chest x-ray on arrival shows the endotracheal tube and chest tube in appropriate positions. Several rib fractures are noted. There is opacity over the left chest that was not present on the initial trauma chest series.
Which of the following is true of this condition?
- A) It occurs in fewer than 25% of patients with significant blunt trauma to the chest.
- B) Treatment includes aggressive intravenous steroid and fluid administration.
- C) The condition starts to resolve in 48–72 hours.
- D) Treatment includes appropriate antibiotics.
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Answer: C Discussion The correct answer is C. The condition, pulmonary contusion, begins to resolve in 48–72 hours. However, 2–3 weeks may be required for complete resolution. Answer A is incorrect. Pulmonary contusion occurs in up to 70% of trauma patients with significant blunt chest trauma. It is usually, but not always, associated with fractured ribs. There may also be a flail segment noted. A chest x-ray demonstrates an infiltrative pattern over the affected area, usually about 1 hour posttrauma, but as long as 6–7 hours later. The condition results in a ventilation-perfusion mismatch and is associated with hypoxemia and an increased A-a gradient. If a patient is able to maintain oxygenation and ventilation, intubation may not be required. Answers B and D are incorrect. Treatment currently only involves intubation as necessary, observation, and tincture of time.
You elect to proceed with pulmonary artery catheter placement due to the severity of this patient’s condition. Overnight he begins to decompensate. The nurse pages you with his vital signs and Swan-Ganz readings: temperature 37.0, pulse 100, respirations 20 (ventilator set at 14), blood pressure 82/30, PCWP 24 mm Hg (normal 5–15), CI 2.0 L/min/m2 (normal 2.5–3.5), SVR 2,000 dyne-sec/cm2 (normal 1,000–1,500), and oxygen delivery of 700 ml/min (normal 900–1,200).
What is the cause of shock at this time?
- A) Hypovolemic shock.
- B) Neurogenic shock.
- C) Cardiogenic shock.
- D) Septic shock.
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Answer: C Discussion The correct answer is C. This patient appears to be in cardiogenic shock (elevated pulmonary capillary wedge pressure, decreased cardiac index). Cardiogenic shock may be caused by myocardial failure, valve failure, dysrhythmias, and tamponade. Treatment is directed at the underlying disorder. Shock is classified into hypovolemic; cardiogenic (pump failure); distributive, secondary to inappropriate arterial dilatation (e.g., adrenal insufficiency, anaphylaxis); neurogenic (following cord injury and loss of autonomic function) or noninfectious systemic (inflammatory response system); and obstructive (venous return compromise from cardiac tamponade, tension pneumothorax, etc.).
Part of the injuries sustained by this patient include burns to the abdomen and back.
Which of the following is FALSE regarding burn wound management in general?
- A) The Parkland formula for fluid resuscitation calls for 2–4 mL/kg/% body surface area burned, with half of the volume in the first 8 hours and the other half over the next 16 hours.
- B) Escharotomy should be performed on all partialthickness burns.
- C) Patients with chemical burns should be treated first with at least half an hour of tap water irrigation.
- D) Prevention of wound infection via topical antimicrobial agents, such as silver sulfadiazine cream, or via silvercoated dressings is the standard of care.
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Answer: B Discussion The correct answer is B. Escharotomy is not necessary unless there is a full-thickness wound that is circumferential and is compromising vascular supply. The thinking about this is changing and some suggest escharot omy of all fullthickness burns. Answer A is a correct statement about the Parkland formula. Answer C is also correct with the addendum that any particulate matter should be brushed off prior to irrigation. Water may activate some substances such as sodium hydroxide. Answer D is also a correct statement.
Which of the following is true regarding fluid administration in burn and dehydrated patients?
- A) A peripheral line will deliver fluid more rapidly than a central line of an equivalent gauge.
- B) Albumin is the fluid of choice in the treatment of burns and should be considered for all patients with significant fluid deficits
- C) D5 one-half normal saline is the preferred fluid for fluid resuscitation in patients other than burn patients.
- D) All of the above are true.
- E) None of the above are true.
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Answer: A Discussion The correct answer is A. A peripheral line will deliver fluid more rapidly than a central line of an equivalent gauge, according to Poiseuille’s law (flow is directly proportional to tube radius and inversely proportional to tube length). The shorter the catheter, the more quickly fluid is delivered (think of a short traffic jam as opposed to a longer one on the same size road). Answer B is incorrect. Albumin is not considered helpful in most situations and is certainly not the fluid of choice. In fact, albumin may increase adverse outcomes. Answer C is also incorrect. Normal saline—or lactated Ringer’s if you are a surgeon—are the fluids of choice in treating dehydration. Remember that lactated Ringer’s is actually slightly hypotonic and thus may worsen cerebral edema. There is no evidence favoring lactated Ringer’s over normal saline.