Pericardiocentesis is often done therapeutically, but may occasionally be done for diagnostic purpose alone. In the interventional era, an important situation in which pericardiocentesis is done is when cardiac tamponade develops following an interventional procedure. This is often life saving or gives time for definitive repair of a perforation.
In the non-interventional setting, pericardiocentesis is done for pericardial effusion which is significant enough to produce a tamponade. Now-a-days echocardiographic confirmation of effusion or hemorrhage into the pericardium is almost invariably done before aspiration. This increases the safety margin of the procedure as the operator gets an idea of the amount effusion and also whether it is localised to certain regions.
Most often the aspiration is done from the subxiphoid route, though the apical route may be rarely resorted to. The risk of the apical route is trauma to the coronary arteries while the risk of cardiac chamber perforation is low from this route as the left ventricular punctures seal off. On the other hand subxiphoid route is unlikely to hit the coronaries, though trauma to right ventricle or atrium can be hazardous in a rare case. Most often the procedure is done under fluoroscopic guidance, though echocardiographic is also useful. The subxiphoid route is used for introducing a pigtail catheter into the pericardial space for intermittent aspiration if the effusion is expected to recollect. After initial percutaneous puncture reaches the pericardial space, which is confirmed by aspirating the fluid out, a guide wire is introduced under fluoroscopic guidance so that it lies behind the left atrium in the oblique sinus. If it is frankly hemorrhagic effusion, attaching a pressure transducer assembly to the needle hub may be useful in differentiating an inadvertent right ventricular puncture as it will show right ventricular pressure tracing. Once the guide wire is in situ, a sheath with dilator is initially introduced, followed by the pigtail catheter through the sheath. The sheath can then be pulled back, leaving the pigtail catheter inside. If the catheter is being retained there after an initial aspiration, a good aseptic coverage of the portion outside the body is needed. Measurement of the pressure within the pericardial space is useful in identifying effusive constrictive pericarditis. Puffs of dye may be used during the initial puncture if there is a doubt regarding the exact position of the needle tip, whether it is in the pericardial space or within a cardiac chamber.
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