Diagnostic echocardiography in an unstable intensive care patient

A previously fit and well 57-year-old gentleman who had recently undergone a colonoscopy and biopsy of a polyp presented with a 4-day history of progressive breathlessness and abdominal discomfort. The day after admission, he became haemodynamically unstable, developed ischaemic legs and suffered a brief cardiac arrest. Blood tests demonstrated a coagulopathy and hypoglycaemia. Continued haemodynamic instability post-arrest and clinical findings of high right-sided heart pressures were investigated by bedside screening echocardiogram. This demonstrated a massive pericardial effusion causing tamponade of the right ventricle. Heavily blood stained pericardial fluid was drained, with marked improvement in haemodynamic stability. Retrospective review of the admission-electrocardiogram (ECG) and chest X-ray demonstrated electrical alternans and cardiac enlargement. The differential diagnosis included bowel malignancy causing a haemorrhagic metastatic pericardial effusion and a type A aortic dissection. Therefore a computerised tomography (CT) scan of chest, abdomen, pelvis and aorta was performed. This was negative for disseminated malignancy and showed a type B aortic dissection, but was inconclusive for a type A aortic dissection. A subsequent transoesophageal echocardiogram confirmed the diagnosis of type B dissection and ruled out a type A dissection. The histology of the colonic polyp was negative for malignancy, but it was subsequently discovered that the patient had metastatic adenocarcinoma from a primary lung cancer diagnosed from pleural fluid cytology. With hindsight the presenting clinical picture was of type B aortic dissection with concurrent but not directly related pericardial tamponade. LEARNING POINTS: Basic echocardiography skills are increasingly being used acutely by physicians' as part of resuscitative care in intensive care unit (ICU) patients. The availability of expert skills in transoesophageal echocardiography are essential in ICU, as demonstrated in this case, where it was needed for discriminating between sub types of aortic dissection. Cardiac tamponade is a clinical diagnosis, although the presence of electrical alternans on an ECG with associated tachycardia is highly suggestive of cardiac tamponade.