Intraoperatory Hemodynamic Monitoring in OLT

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.

• New Onset Renal Failure [Time frame: From the end of the surgical procedure until discharge from hospital (whole duration of Hospital admission, considered within 3 months)]
• New Onset Neurological disturbances [Time frame: From the end of surgery for the first 24 hours after withdrawal of sedation in the ICU.]
• New Onset Cardiological events [Time frame: From the end of the surgical procedure until discharge from hospital (whole duration of Hospital admission, considered within 3 months)]
• Cumulative Incidence of Early Graft Dysfunction / Primary Non Function [Time frame: According to definition (up to 7 days after procedure).]
• Duration of Post-Reperfusion Syndrome [Time frame: First 5 minutes after portal graft anastomosis.]
• Total amount of fluids administered during surgery [Time frame: From incision to end of procedure (for the entire surgical procedure in a period ranging from 0 to 24 hours)]
• Cumulative dosage of vasoactive amines administered during surgery [Time frame: From incision to end of procedure (for the entire surgical procedure in a period ranging from 0 to 24 hours)]
• Cumulative incidence of adverse events attributable to the hemodynamic monitoring used [Time frame: From the end of the surgical procedure until discharge from hospital (whole duration of Hospital admission, considered within 3 months)]
• Duration of ICU admission [Time frame: From a minimum of 2 days to a maximum of 3 months]
• Mortality at 30 and 90 days [Time frame: 1 month and 3 months after surgical procedure.]