Sujet de la discussion : MedeSpace.Net :: United State Médical Licensing Examination

Publié par La Pharmacienne le 10-12-2008 16:50
#12

Bonsoir:

Choose the one best response to this question:

4. A 73-year-old female develops substernal chest pain, severe nausea, and vomiting while mowing the lawn. In the emergency department she has cool extremities, right arm and left arm blood pressure of 85/70 mmHg, heart rate of 65/min, clear lungs, and no murmurs. She has no urine output. A Swan-Ganz catheter is placed and reveals cardiac index of 1.1 L/min per m2, PA pressure of 20/14 mmHg, PCW pressure of 6 mmHg, and RA pressure of 24 mmHg. The patient most likely has:

A. gram-negative sepsis
B. occlusion of the left main coronary artery
C. occlusion of the right coronary artery
D. perforated duodenal ulcer
E. ruptured aortic aneurysm


PA pressure = Pulmonary Artery pressure
PCWP = Pulmonary Capillary Wedge Pressure = c'est la PCP ou la PAPO
RA pressure = Right Atrial pressure = pression de Oreillette Droite
Blood pressure = pression artérielle
Heart rate = pouls ( parfois ils parlent de "pulse" )
infarction = infarctus
Right ventricular failure = insuffisance ventriculaire droite


Answer:
The answer is C.
This patient has a right ventricular infarction. The combination of findings consistent with bradycardia, cardiogenic shock, low normal left ventricular and PA pressures, and markedly elevated right atrial pressure is consistent with acute right ventricular (RV) failure. An acute pulmonary embolus may also cause acute RV failure, but the PA pressure is usually elevated. RV infarction is usually due to occlusion of the right coronary artery; the bradycardia is due to sinus or AV node ischemia. Right-sided precordial ECG will show ST-segment elevation. Occlusion of the left main artery will cause cardiogenic shock, but the PCW pressure will be elevated. Perforated duodenal ulcer and ruptured aortic aneurysm will cause hypovolemic shock with low RA and PCW pressures. Gram-negative sepsis will generally have an normal or increased cardiac index with normal filling pressures and low blood pressure