Hemodynamic monitoring during liver transplantation: A state of the art review.

Orthotopic liver transplantation can be marked by significant hemodynamic instability requiring the use of a variety of hemodynamic monitors to aide in intraoperative management. Invasive blood pressure monitoring is essential, but the accuracy of peripheral readings in comparison to central measurements has been questioned. When discrepancies exist, central mean arterial pressure, usually measured at the femoral artery, is considered more indicative of adequate perfusion than those measured peripherally. The traditional pulmonary artery catheter is less frequently used due to its invasive nature and known limitations in measuring preload but still plays an important role in measuring cardiac output (CO) when required and in the management of portopulmonary hypertension. Pulse wave analysis is a newer technology that uses computer algorithms to calculate CO, stroke volume variation (SVV) and pulse pressure variation (PPV). Although SVV and PPV have been found to be accurate predicators of fluid responsiveness, CO measurements are not reliable during liver transplantation. Transesophageal echocardiography is finding an increasing role in the real-time monitoring of preload status, cardiac contractility and the diagnosis of a variety of pathologies. It is limited by the expertise required, limited transgastric views during key portions of the operation, the potential for esophageal varix rupture and difficulty in obtaining quantitative measures of CO in the absence of tricuspid regurgitation.