Pericardial Disease in 2019: What Shall I Do After Pericardiocentesis?

The pericardium consists of two layers: the outer (fibrous pericardium) and the internal (serous pericardium). The serous pericardium forms an enclosed pericardial cavity that is lined with mesothelial cells, and is composed of a parietal layer and a visceral layer. The volume of pericardial fluid is typically about 0.25 ml / kg in dogs. Lymphatic drainage of the pericardium is carried out by lymphatic vessels that drain into the tracheal or sternal lymph nodes, or into the pleural veins that drain on the right side. Normally, intrapericardial pressure (that of the pericardial space) is zero, exerting no negative effect on the cardiac filling. However, if the pericardial space is filled, in particular in a quick manner, it leads to a large increase in intrapericardial pressures, and changes in ventricular filling.
Cardiac tamponade is not "all or nothing", and progresses and varies in intensity with increasing intrapericardial pressure. Initially, intracardiac pressure is still greater than the pericardial pressure, and cardiac filling is decreased (according to Starling's law), although only slightly. With increasing intrapericardial pressure, stage 2 is reached, and the pericardial pressure is identical or lower than the pressure of the right atrium and the filling pressure of the right ventricle. In stage 3, intrapericardial pressure can rise above the pressures of left ventricular filling. [...]