In today's VETgirl online veterinary CE podcast, we will be evaluating two methods of pericardiocentesis based off a study by Cook et al entitled Prospective evaluation of pericardial catheter placement versus needle pericardiocentesis in the management of canine pericardial effusion. Pericardial effusion in dogs is a condition we see with some degree of frequency in the ER. The urgency of this condition arises from the buildup of trapped fluid in the small sac surrounding the heart, located between the pericardial lining and the myocardium. Normally this space is so small that you can't really see it on an emergency ultrasound scan without a cardiologist and a diagnostic ultrasound. When enough fluid builds up in the pericardial sac, this space becomes easier to see on emergency ultrasounds. But more importantly, as the fluid accumulates, the pressure in this trapped space compresses the heart chambers, preventing adequate filling of the heart, and results in less blood exiting the heart, and so less blood and oxygen is supplied to our vital organs. This condition is called cardiac tamponade and represents one of the causes of “obstructive shock.” Clinical signs that may clue us in to the presence of cardiac tamponade include Beck's triad of: 1) low blood pressure 2) muffled heart sounds 3) and jugular venous distention, and often the patient is also tachycardic which is the body's compensatory response to the lower cardiac filling volumes.