'Tamponade' following cardiac surgery: terminology and echocardiography may both mislead

Echocardiography is widely considered the gold standard for the diagnosis of tamponade. While a relatively common complication of cardiac surgery in adults, determining whether haemodynamics are compromised by a pericardial collection early post-operatively can be difficult. The aim of the current study was to determine the nature and magnitude of the diagnostic challenge posed by cardiac tamponade following cardiac surgery. We therefore examined the accuracy of echocardiography in the diagnosis of tamponade in this patient group.

From January 2000 to January 2002, 2297 adult patients underwent cardiac surgery in a tertiary referral cardiothoracic centre. A retrospective analysis of prospectively collected data, from all patients diagnosed with post-operative bleeding and/or tamponade was performed. Data included demographics, surgery, anticoagulation/anti-platelet medication, clinical/echocardiographic features of tamponade and surgical findings at re-exploration.

The diagnosis of 'tamponade' was confirmed at re-exploration in 148 patients. When it occurred early (<72 h) following cardiac surgery trans-thoracic echocardiography failed to visualise the majority of collections (60%), necessitating trans-esophageal echocardiography. Effusions were small (160+/-17 ml) and localised (92%), showing no echocardiographic features of classical tamponade (79%). Where patients developed tamponade late (>72 h) following cardiac surgery, clinical features were atypical, effusions larger (640+/-71 ml, P<0.0001)) and global (77%). Classical echocardiographic features of tamponade were usually present (70%) and readily visualised using trans-thoracic echocardiography.

Haemodynamically significant pericardial collections occurring early following cardiac surgery rarely cause classical clinical or echocardiographic features of tamponade. Recognition of this as a separate diagnostic entity is necessary to ensure appropriate surgical intervention is not delayed.