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A 59-year-old woman with acute congestive heart failure is admitted to the intensive care unit. She was transferred from the medical floor where she was found to be in florid pulmonary edema with hypoxemia and respiratory distress. She was intubated by the anesthesia airway team at that time of transfer. She was transferred to the medical intensive care unit for aggressive diuresis and ventilator management. On arrival to the unit, it is determined that the patient will require frequent arterial blood samplings to monitor her ventilation status. A decision is made to place an indwelling arterial catheter for this purpose. The artery that carries with it the highest risk for complications when used for arterial cannulation is the
A. brachial artery
B. dorsalis pedis artery
C. femoral artery
D. radial artery
E. ulnar artery
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A. brachial artery
associated with median nerve injury
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The correct answer is A. A concern when indwelling arterial catheters are placed is that the vessel thromboses. If this occurs, perfusion to the tissues distal to the thrombosis depends upon collateral flow. The brachial artery is an end artery and its collaterals are distal to the insertion site in the antecubital fossa. Therefore, if it were to thrombose, there would be no inflow to the forearm.
The dorsalis pedis (choice B) is found on the dorsum of the foot and has extensive collateral flow via the posterior tibial artery.
The femoral (choice C) is located in the anterior leg at the floor of the femoral triangle and is sub-served by many collaterals.
The radial (choice D) and the ulnar (choice E) are the most common sites for insertion of an arterial catheter. These two arteries are collaterals of one another and it is very rare that the ulnar (the less used artery for cannulation) is not patent.
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A 67-year-old man is seen in the emergency department for syncope. His wife brought him to the hospital and reports that over the past few days he has had 4 syncopal events with loss of consciousness. During these episodes, she reports that she felt his pulse and that his heart rate was very slow, less than 30/min. The patient reports that occasionally he feels his heart beat very fast within his chest. His past medical history is otherwise remarkable for coronary artery disease and a myocardial infarction 8 months ago. A follow-up echocardiogram after the myocardial infarction revealed depressed left ventricular function with an estimated ejection fraction of 45%. There was mild left ventricular free wall dyskinesis. In the emergency department, while attached to the monitors, the patient becomes asystolic. He is positioned flat on his back with a CPR board placed under him and his airway is secured. The most appropriate next step is to
A. administer lytic therapy, intravenously
B. begin transcutaneous pacing
C. give amiodarone, intravenously
D. give epinephrine, intravenously
E. perform an emergency PTCA and stenting
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D. give epinephrine, intravenously
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The correct answer is B. It appears from this patient's history that he has sick-sinus syndrome with alternating tachycardia and bradycardia. This condition is common in patients with severe coronary disease as this patient has. He has advanced ischemic cardiomyopathy and is at high risk for a number of arrhythmias. For asystole, especially in an emergency department, the treatment of choice is pacing until native rhythm can be restored. In fact, this patient will require implantation of a permanent pacer.
Since there is no evidence of ischemia at this time intravenous lytic therapy (choice A) is inappropriate.
Amiodarone intravenously (choice C) is inappropriate in this setting. Amiodarone has been shown to be superior to lidocaine in the management of pulseless VT/VF after cardioversion or countershock and epinephrine. It has taken a class IIb indication (demonstrated benefit) in these scenarios. It is also used as an adjunct to electrical cardioversion of reentrant ventricular tachycardia and rapid atrial tachycardias. It has no role in management of asystole.
Epinephrine (choice D) is used as core therapy for many algorithms on ACLS, including asystole. However, it is not to be used before pacing when the latter is available. Pacing restores flow, while epinephrine makes the restoration of flow more likely. Pacing is superior to drug delivery for this reason.
Although profound bradycardia (heart block) and asystole can be seen with ischemia, the treatment for the rhythm is pacing and atropine. To manage the underlying etiology, emergency PTCA and stenting (choice E), if ischemia were found, would be appropriate in settings where catheterization labs are rapidly available. In hospitals where such facilities are not available at all hours, intravenous lytic therapy is used. For this patient however, there is no evidence of ischemia at this time.
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A 23-year-old motor vehicle accident victim is brought to the emergency department. She was a restrained passenger in a head-on collision. She has no medical history and has no allergies. Her injuries are limited to a fractured right femur. She is awake and talking to you coherently. Her temperature is 37 C (98.6 F), blood pressure is 99/67 mm Hg, pulse is 120/min, and respirations are 24/min. Examination is unremarkable. Laboratory studies show that her hematocrit is 18%, prothrombin time is 12.4 seconds, and partial thromboplastin time is 29 seconds. Her blood type is A-. The most appropriate intervention at this time is to
A. administer type A- packed red blood cells
B. administer type A+ packed red blood cells
C. administer type AB- packed red blood cells
D. administer type B- packed red blood cells
E. administer type O+ packed red blood cells
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A 27-year-old man comes to the emergency department because of increasing fatigue, malaise, chills, and low-grade fevers over the last 2 weeks. He reports no recent sick contacts and denies any significant past medical history. The patient does mention that he uses heroin frequently but not since last week. His temperature is 38.8 C (101.8 F), blood pressure is 85/60 mm Hg, and heart rate is 120/min. On physical examination, the patient appears gaunt, malnourished, and dehydrated. A faint systolic murmur is audible on cardiac auscultation. Needle tracks are found at both antecubital fossa. Petechiae are noted across his back and splinter hemorrhages are found under the nail beds of his right hand. Laboratory studies show:
wbc21000
hct 33
platelet 2.5 lac
bun 46 creat 1.6
A chest radiograph shows normal lungs and cardiac silhouette. An electrocardiogram reveals sinus tachycardia. Urinalysis shows 2+ proteinuria, 3+ red blood cells, and 1+ ketones. The patient is admitted to the hospital where he becomes progressively more confused and disoriented. Three sets of blood cultures are drawn and intravenous fluids are initiated. The most appropriate next step in management is to
A. begin nafcillin and gentamicin, intravenously
B. begin penicillin and clindamycin, intravenously
C. obtain an immediate evaluation by cardiac surgery
D. order an urgent transesophageal echocardiography
E. start methadone therapy
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