Ok, so apparently this case was too easy as everyone answered correctly.  Just to refresh your memories:

A 42-year old man who was in a motor vehicle crash comes to the ED where you clear his airway. He has intact, normal breath sounds bilaterarlly and appears to be ventilating and oxygenating well. Initial assessment of the cardiovascular system reveals hypotension with a BP of 80/60, a heart rate of 110 bpm, distended neck veins, and muffled heart sounds on auscultation. You perform a procedure that quickly corrects his blood pressure as well as confirms your suspected diagnosis. You performed..

As everyone selected, you performed a pericardiocentesis.  I chose this case particularly after our first case with the hypotension and distended neck veins which were similar presenting factors in this case.  The difference however in other findings led to a completely different diagnosis as well as treatment.  For instance, in our last case we had absent lung sounds which led to the diagnosis of pneumothorax.  Here, the lung sounds were present, but it was the heart sounds that were muffled leading to the diagnosis of tamponade and to a pericardiocentesis. 

Just as a final note, the classical findings in a tamponade are known as “Beck’s Triad”: Hypotension, Distended Neck Veins and Muffled Heart Sounds

Please let me know if you have any questions.

Glenn