A previously healthy 24-year-old man is brought to the emergency department after a bicycle crash.  The patient was mountain biking downhill when he struck a prominent tree root and was thrown from his bike.  He tried to brace his fall with his hands, but his chest struck a large rock as he landed.  He did not hit his head or lose consciousness.  The patient has moderate central chest pain and severe right wrist pain.  Blood pressure is 142/86 mm Hg, pulse is 110/min, and respirations are 20/min.  Oxygen saturation is 98% on room air.  Physical examination is significant for sternal bruising with point tenderness, abrasions on both palms, and a deformed right wrist with an overlying laceration.  Breath sounds, heart sounds, and abdominal examination are normal.  Focused assessment with sonography for trauma is negative for free intraabdominal or pericardial fluid.  Noncontrast CT scan of the chest reveals a hairline sternal fracture.  Radiographs of the right wrist reveal a severely displaced, open fracture of the right distal radius.  The patient is hospitalized for operative irrigation, debridement, and fixation of the wrist fracture.  Throughout the day, the patient is noted to be persistently tachycardic even though he is afebrile and normotensive, with normal respirations and oxygen saturation.  Pain control is adequate.  ECG shows sinus tachycardia with frequent premature ventricular contractions.  Which of the following is the best next step in management of this patient?

25- year-old student involved in a road traffic accident, was brought to the emergency department in shock. Examination showed low blood pressure and tenderness on the left mid- and posterior axillary line. X-ray revealed that his 10th ribs was fractured near their angle on the left

A 45-year-old man comes to the emergency department due to a 1-day history of constant upper abdominal pain, nausea, and several episodes of vomiting.  The pain is partially relieved by sitting up or bending forward.  He has also had mild shortness of breath.  The patient's other medical history includes hyperlipidemia and hypertension.  He uses tobacco and alcohol.  There is a family history of coronary artery disease and hypertension.  Temperature is 38.1 C (100.6 F), blood pressure is 110/70 mm Hg, pulse is 114/min, and respirations are 22/min.  There is dullness to percussion and decreased breath sounds at the left lung base.  Abdominal examination shows epigastric tenderness.  Laboratory results are as follows:Hematocrit 44%Leukocytes 16,000/mm3Calcium 7.8 mg/dLGlucose 250 mg/dLWhich of the following plays a principal role in initial management of this patient's current condition? A.Antiplatelet agents B.Broad-spectrum antibiotics C.Calcium gluconate D.Exploratory laparotomy E.Insulin infusion F.Isotonic crystalloids G.Proton pump inhibitors

A 57-year-old woman is brought into the emergency department because of the sudden onset of severe left-sided chest pain and shortness of breath. She had flown back to the United States yesterday following a tour of Southeast Asia. Other than feeling tired after her long trip, she was in her usual state of good health, but this afternoon she had the sudden onset of stabbing left chest pain and noted severe shortness of breath. She denies any previous history of peripheral vascular, cardiac, or respiratory disease. Past medical history is unremarkable, and she is not currently taking any medications. On examination, the patient is in severe discomfort. Temperature is 100.5°F (38°C) orally, pulse 130, respirations 26, and BP 130/90. Pulse oximetry reveals an O2 saturation of 88% while the patient is breathing room air. Physical examination is otherwise unremarkable. Stat labs show normal kidney function. A chest radiograph and ECG are obtained.  What is the most appropriate action at this time?

A 58-year-old man comes to the emergency department due to sudden onset of severe right leg pain several hours ago; the leg has since become numb.  He has never had similar symptoms and has no history of trauma, fever, or chills.  The patient recently had an acute anterior wall myocardial infarction that resulted in cardiogenic shock; he is undergoing cardiac rehabilitation.  Temperature is 36.7 C (98.1 F), blood pressure is 120/70 mm Hg, pulse is 90/min and regular, and respirations are 16/min.  Cardiopulmonary examination is unremarkable.  Compared with the left leg, the right leg appears pale and is cool to the touch.  In the right lower extremity, the popliteal pulse is normal, but more distal pulses are not palpable.  Pulses in the other extremities are normal.  Neurologic examination shows loss of sensation over the dorsum of the right foot and mild weakness with dorsiflexion.  Which of the following is the most likely cause of this patient's symptoms?

A 29-year-old woman is brought to the emergency room after falling off her third floor apartment balcony. The patient suffered blunt abdominal trauma, a right femur fracture, and a left humeral fracture. On physical examination, her blood pressure is 70/30 mmHg and her heart rate is 120 beats per minute. After the administration of 5 units of packed red blood cells, the patient reports a “pins and needles” sensation on her distal toes and around her mouth. Laboratory testing confirms a calcium level of 6.9 mg/dL and a magnesium level of 1.1 mEq/L. Which of the following is the underlying cause of this patient's hypocalcemia and hypomagnesemia?