The goal of this clinical trial is to compare two different hemodynamic monitoring techniques during orthotopic liver transplantation.

The main question it aims to answer is: if using a different hemodynamic monitoring might help reducing the intraoperative hypotension time. Participants will be randomized to one of two arms of hemodynamic monitoring:

• conventional monitoring with pulmonary artery catheter
• monitoring with transesophageal echocardiography Researchers will compare the two groups to see if there is any difference in the intraoperatory hypotension time and in secondary outcomes such as organ dysfunctions or mortality.

Intraoperative hypotension is an independent risk factor for the development of complications and postoperative mortality. In non-cardiac surgery, in particular, the time spent under a mean arterial pressure (MAP) of 55 correlates with an increase in myocardial ischemic damage, acute renal failure, and 30-day mortality.

Orthotopic liver transplantation (OLT) is a complex and risky procedure both from a surgical and an anesthesiological standpoint. Difficulties in hemodynamic management arise from the pathophysiological alterations in cirrhotic patients, high-impact surgical procedures (e.g., caval and portal clamping), high bleeding risk, and post-reperfusion syndrome (PRS).

In liver transplantation, the pulmonary artery catheter (PAC) remains the "gold standard" for hemodynamic instability monitoring and is placed in over 90% of patients in the USA.

Transesophageal echocardiography (TEE) is a semi-invasive ultrasound monitoring procedure. As recognized in a recent position paper by the Society for the Advancement of Transplant Anesthesia (SATA), there has been a considerable increase in the use of TEE during OLT in recent years, despite the lack of randomized controlled trials (RCTs) confirming its effectiveness. According to the SATA task force, the increased intraoperative use of TEE is imputable to the chance for a more thorough understanding of hemodynamic pathophysiology and the possibility of identifying new findings, otherwise not identifiable with PAC (cardiac tamponade, gas embolism, intracardiac thrombus, papillary muscle/chordae rupture, left ventricular outflow tract obstruction, etc.). The overall complication rate of TEE in the articles analyzed by SATA was found to be 0.47% compared to 5-10% for PAC complications, thus supporting the safety of the procedure.

Currently, there is a lack of published RCTs comparing these monitoring methods to determine if there is an optimal intraoperative monitoring system during OLT.

The research hypothesis of this study is that TEE monitoring allows for better hemodynamic management during OLT, reducing the duration of hypotension and providing better guidance fo fluid-pharmacological therapy compared to standard monitoring (PAC).

The primary outcome is to compare the impact of two different hemodynamic monitoring systems (TEE and PAC) on intraoperative hemodynamic optimization during OLT.

Inclusion Criteria:

• Candidate for Liver Transplantation
• Acceptance of informed consent to participate in the study.

Exclusion Criteria:

• Bleeding esophageal varices
• Bleeding gastro-esophageal ulcer
• Gastro-esophageal anomalies (congenital, acquired or post-surgical)