Hemodynamic monitoring in liver transplantation 'the hemodynamic system'

Hemodynamic Monitoring During Liver Transplantation for Patients on Perioperative Extracorporeal Membrane Oxygenation (ECMO) Support: A Narrative Review

Background and Objectives: Indications for liver transplants are increasing worldwide due to the growing number of transplants performed on patients with significant cardiovascular and respiratory risk factors. Additional support for this trend comes from the growing use of marginal organs, which is made possible by donations made after circulatory death (DCD). Liver transplantation (LT) in such high-risk patients may be challenging and may require perioperative Extracorporeal Membrane Oxygenation (ECMO). There is a lack of evidence on the best hemodynamic monitoring techniques for patients undergoing ECMO support during the perioperative period of LT. This review aims to provide a comprehensive overview of the hemodynamic monitoring standards of patients supported by ECMO before, during, and after LT. Materials and Methods: Comprehensive research was conducted through the PubMed database, and 153 articles regarding patients who needed perioperative ECMO support were found. Among these, 18 articles were finally included in our analysis as the authors specified hemodynamic monitoring techniques and data. The articles included case reports, letters to the editor, and correspondence. Results: We identified 20 cases of patients supported by ECMO as a planned preoperative strategy (9 patients), as a rescue therapy during surgery (7 patients), and as a postoperative support (4 patients). Cardiac catheterism and echocardiography (transthoracic and transesophageal) were the authors' most cited hemodynamic monitoring techniques. Conclusions: Data on hemodynamic monitoring methods used to manage patients supported by ECMO during the whole perioperative period of LT are poor and derived from descriptive low-quality studies. However, a multimodal approach that includes continuous monitoring of pulmonary pressures and echocardiography can increase diagnostic accuracy and improve the decision-making process to manage this complex patient population.

Bridging the critically ill patient with acute to chronic liver failure to liver transplantation

Liver transplantation (LT) has emerged as an effective therapy for severe forms of acute-on-chronic liver failure (ACLF), an entity characterized by the development of multiorgan failure and high short-term mortality. The aim of critical care management of ACLF patients is to rapidly treat precipitating events and aggressively support failing organs to ensure that patients may successfully undergo LT or, less frequently, recover. Malnutrition and sarcopenia are frequently present, adversely impacting the prognosis of these patients. Management of critical care patients with ACLF is complex and requires the participation of different specialties. Once the patient is stabilized, a rapid evaluation for salvage LT should be performed because the time window for LT is often narrow. The development of sepsis and prolonged organ support may preclude LT or diminish its chances of success. The current review describes strategies to bridge severe ACLF patients to LT, highlights the minimal evaluation required for listing and the currently suggested contraindications to proceed with LT, and addresses different aspects of management during the perioperative and early posttransplant period.

A comparison of hemodynamic measurement methods during orthotopic liver transplantation: evaluating agreement and trending ability of PiCCO versus pulmonary artery catheter techniques

BACKGROUND

Significant hemodynamic changes occur during liver transplantation, emphasizing the importance of precious and continuous monitoring of cardiac output, cardiac index, and other parameters. Although the monitoring of cardiac output by pulse indicator continuous cardiac output (PiCCO) was statistically homogeneous compared to the clinical gold standard pulmonary artery catheterization (PAC) in previous studies of liver transplantation, there are fewer statistical methods for the assessment of its conclusions, and a lack of comparisons of other hemodynamic parameters (e.g., SVRI, systemic vascular resistance index). Some studies have also concluded that the agreement between PiCCO and PAC is not good enough. Overall, there are no uniform conclusions regarding the agreement between PiCCO and PAC in previous studies. This study evaluates the agreement and trending ability of relevant hemodynamic parameters obtained with PiCCO compared to the clinical gold standard PAC from multiple perspectives, employing various statistical methods.

METHODS

Fifty-two liver transplantation patients were included. Cardiac output (CO), cardiac index (CI), SVRI and stroke volume index (SVI) values were monitored at eight time points using both PiCCO and PAC. The results were analyzed by Bland-Altman analysis, Passing-bablok regression, intra-class correlation coefficient (ICC), 4-quadrant plot, polar plot, and trend interchangeability method (TIM).

RESULTS

The Bland-Altman analysis revealed high percentage errors for PiCCO: 54.06% for CO, 52.70% for CI, 62.18% for SVRI, and 51.97% for SVI, indicating poor accuracy. While Passing-Bablok plots showed favorable agreement for SVRI overall and during various phases, the agreement for other parameters was less satisfactory. The ICC results confirmed good overall agreement between the two devices across most parameters, except for SVRI during the new liver phase, which showed poor agreement. Additionally, four-quadrant and polar plot analyses indicated that all agreement rate values fell below the clinically acceptable threshold of over 90%, and all angular deviation values exceeded ± 5°, demonstrating that PiCCO is unable to meet the acceptable trends. Using the TIM, the interchangeability rates were found to be quite low: 20% for CO and CI, 16% for SVRI, and 13% for SVI.

CONCLUSIONS

Our study revealed notable disparities in absolute values of CO, CI, SVRI and SVI between PiCCO and PAC in intraoperative liver transplant settings, notably during the neohepatic phase where errors were particularly pronounced. Consequently, these findings highlight the need for careful consideration of PiCCO's advantages and disadvantages in liver transplantation scenarios, including its multiple parameters (such as the encompassing extravascular lung water index), against its limited correlation with PAC.