The role of trans-oesophageal echocardiography for perioperative cardiovascular monitoring during orthotopic liver transplantation

Abstract

Patients undergoing orthotopic liver transplantation frequently display considerable physiological changes during the procedure as a result of both the disease process and the surgery. Anaesthesia is often challenging and relies upon advanced monitoring techniques to provide data pertinent to peri-operative management. Traditionally the pulmonary artery flotation catheter has been regarded as the gold standard for cardiac output and right heart monitoring. This review examines whether trans-oesophageal echocardiography merits a place in the continuing evolution of this technically advanced and challenging anaesthetic field. The anaesthetic management of patients undergoing orthotopic liver transplantation (OLT) is complicated and often challenging. The procedure itself predisposes to inherent cardiovascular instability and despite pre-operative screening for suitability for transplantation, patients frequently present with both independent coexistent pathologies and dysfunction of other physiological systems consequent upon, or associated with the cause of their end-stage liver disease. Rapid and potentially catastrophic haemodynamic, metabolic and coagulation changes frequently occur intraoperatively which require early and accurate identification in order to allow expedient management. Pulmonary artery flotation catheterisation (PAFC) is an established intravascular monitoring tool which, whilst providing direct measurements, only indirectly offers left sided cardiac information. It is unable to demonstrate structural abnormality and provides limited dynamic information. By contrast, trans-oesophageal echocardiography (TOE) provides direct visualisation of cardiac structure, filling and dynamic function, and has the distinct advantage of remaining a relatively non-invasive procedure. PATHOGENESIS AND PHYSIOLOGY OF CARDIOVASCULAR INSTABILITY DURING ORTHOTOPIC LIVER TRANSPLANTATIONPerioperative cardiovascular instability may result from pre-existent comorbidity both related and unrelated to the primary liver disease as well as perioperative changes resulting directly from the procedure.Patients with end stage liver disease often have deranged cardiovascular physiology, presenting with a high cardiac output and a low systemic vascular resistance. This low cardiac afterload has the potential to mask coexistent cardiovascular disease from pre-operative detection.A recent review of cardiac morbidity and mortality in patients presenting for OLT suggests that the incidence of significant pathology is much higher than has been previously anticipated. 1 Indeed Carey et al. demonstrated that 32% of patients over the age of 50 put forward for OLT pre-operative evaluation had moderate or severe coronary artery disease at coronary angiography. Whilst 58% of these were known to have coronary Abbreviations: OLT, orthotopic liver transplantation; PAFC, pulmonary artery flotation catheter; TOE, trans-oesophageal echocardiography Address reprint requests to

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