Aetiology and management of acute cardiac tamponade.
OBJECTIVE
To review current concepts in the aetiology and management of patients with cardiac tamponade.


METHODS
A review of articles reported on acute cardiac tamponade.


RESULTS
Cardiac tamponade is defined as a haemodynamically significant cardiac compression caused by pericardial fluid. The fluid may be blood, pus, effusion (transudate or exudate) or air and treatment involves correction of the cardiac diastolic restriction by removing pericardial fluid during either pericardiocentesis or thoracotomy. Pericardiocentesis is usually performed for urgent management of an acute tamponade. A thoracotomy is required when a tamponade exists following coronary artery bypass grafting, cardiac rupture, penetrating or closed cardiac trauma and aortic dissection or where a pericardial clot is likely. Removal of pericardial fluid by percutaneous catheterisation of the pericardial sac traditionally uses the subxiphoid 'blind' approach., However, pericardial aspiration is often currently performed under transthoracic echocardiographic guidance with the commonest site of needle entry being on the chest wall at or near the apex and the needle directed perpendicular to the skin. The pericardial fluid is drained using an indwelling 'pigtail' catheter, preferably with close monitoring of the pulmonary artery wedge pressure, as rapid removal of large volumes of pericardial fluid (> 500 mL) may result in a 'decompressive syndrome' causing pulmonary oedema. The fluid is sent for culture and Gram-stain and analysed for glucose, protein, lactate dehydrogenase, haemoglobin and white cell count. If appropriate the fluid is also analysed for amylase, and cholesterol and sent for cytology, serology and parasitic studies and viral, mycobacterial and fungal cultures.


CONCLUSIONS
Cardiac tamponade may present as an acute or subacute syndrome of elevated central venous pressure and hypotension. Pericardiocentesis using echocardiographic guidance and right heart catheter control is often the method of choice for acute removal of fluid.
Department of Anaesthesia and Intensive Care, Mater Misericordiae Hospital, Dublin, Ireland.
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Collins