Hemodynamic monitoring in liver transplantation 'the hemodynamic system'.

PURPOSE OF REVIEW: The purpose of this article is to provide a comprehensive review of hemodynamic monitoring in liver transplantation. RECENT FINDINGS: Radial arterial blood pressure monitoring underestimates the aortic root arterial blood pressure and causes excessive vasopressor and worse outcomes. Brachial and femoral artery monitoring is well tolerated and should be considered in critically ill patients expected to be on high dose pressors. The pulmonary artery catheter is the gold standard of hemodynamic monitoring and is still widely used in liver transplantation; however, it is a highly invasive monitor with potential for serious complications and most of its data can be obtained by other less invasive monitors. Rescue transesophageal echocardiography relies on few simple views and should be available as a standby to manage sudden hemodynamic instability. Risk of esophageal bleeding from transesophageal echocardiography in liver transplantation is the same as in other patient populations. The arterial pulse waveform analysis based cardiac output devices are minimally invasive and have the advantage of real-time beat to beat monitoring of cardiac output. No hemodynamic monitor can improve clinical outcomes unless integrated into a goal-directed hemodynamic therapy. The hemodynamic monitoring technique should be tailored to the patient's medical status, surgical technique, and the anesthesiologist's level of expertise. SUMMARY: The current article provides a review of the current hemodynamic monitoring systems and their integration in goal-directed hemodynamic therapy.

The evolving role of ECMO in liver transplantation.

PURPOSE OF REVIEW: To review the indications for extra-corporeal membrane oxygenation (ECMO) in liver transplantation (LT) recipients and their optimal management on ECMO. RECENT FINDINGS: Recent studies have reported a 30-40% survival rate among LT recipients that receive ECMO. Increasingly, case reports have documented successful outcomes of LT performed for patients on preoperative ECMO. Outcomes appear to be superior with patients in the immediate peri-LT period with reversible causes of severe, acute respiratory, and/or cardiovascular collapse. Mortality is most commonly secondary to infection. Volume optimization with CRRT may improve outcomes and perfusion to the graft, especially for patients on veno-arterial ECMO. There is little consensus on management of anticoagulation in these patients, but it can likely be held temporarily when the patient is coagulopathic and/or experiencing bleeding complications. SUMMARY: ECMO should be considered in the peri-LT period for patients with severe, acute, and reversible causes of respiratory and/or cardiovascular collapse, with acceptable outcomes in patients that would otherwise not be expected to survive. Management of the post-LT patient on ECMO is challenging with a slowly enlarging body of literature to inform decision making.

Liver Transplantation in Patients with Sickle Cell Disease in the United States.

BACKGROUND: Up to 30% of patients with sickle cell disease (SCD) develop chronic liver disease via etiologies including sickle cell hepatopathy, acquired viral hepatitis, or secondary hemochromatosis. It is unclear how many patients with SCD ultimately undergo liver transplantation (LT) and what factors are associated with survival after LT. In this study, we examined LT outcomes in these patients by reviewing the Scientific Registry of Transplant Recipients (SRTR) and our institutional experience. METHODS: Analysis of the SRTR identified 23 LT recipients and five simultaneous liver and kidney transplantation (SLKT) recipients with SCD. Patient demographics and graft and patient survival were analyzed. Two patients with SCD at our institution underwent SLKT. RESULTS: Review of the SRTR revealed that recipients with SCD had significantly higher model for end-stage liver disease scores (33 versus 21, P = 0.004), preoperative intensive care unit admission (43.5% versus 19.1%, P = 0.007), preoperative dialysis (17.4% versus 4.9%, P = 0.009), and were more likely to be status 1 (26.1% versus 12.1%, P = 0.041) when compared with the reference population of African American LT recipients. Despite being higher risk at the time of LT, patients with SCD had equivalent posttransplant graft and patient survival when compared with the reference population (P = 0.5 and P = 0.2, respectively) and a 2:1 propensity score-matched group (P = 0.5 and P = 0.2, respectively). Two recent SLKT recipients with SCD from our institution have performed well with stable allograft function. CONCLUSIONS: Data from the SRTR demonstrate that patients with SCD can expect equivalent graft and patient survival after LT despite exhibiting more comorbidities at the time of LT. The low number of patients with SCD who underwent LT in the SRTR in comparison with the rate of chronic liver disease in this population raises the question as to whether a disparity in access to LT exists for this complex population.

Intraoperative hemodialysis during liver transplantation: a decade of experience.

Liver transplantation (LT) for patients with renal dysfunction is frequently complicated by major fluid shifts, acidosis, and electrolyte and coagulation abnormalities. Continuous renal replacement therapy (CRRT) has been previously shown to ameliorate these problems. We describe the safety and clinical outcomes of intraoperative hemodialysis (IOHD) during LT for a group of patients with high Model for End-Stage Liver Disease (MELD) scores. We performed a retrospective study at our institution of patients who underwent IOHD from 2002 to 2012. Seven hundred thirty-seven patients underwent transplantation, and 32% received IOHD. The mean calculated MELD score was 37, with 38% having a MELD score ≥ 40. Preoperatively, 61% were in the intensive care unit, 19% were mechanically ventilated, 43% required vasopressor support, and 80% were on some form of renal replacement therapy at the time of transplantation, the majority being on CRRT. Patients on average received 35 U of blood products and 4.8 L of crystalloids without significant changes in hemodynamics or electrolytes. The average urine output was 450 ml, and the average amount of fluid removal with dialysis was 1.8 L. The 90-day patient and dialysis-free survival rates were 90% and 99%, respectively. One-year patient survival rates based on the pretransplant renal replacement status and the MELD status were not statistically different. This is the first large study to demonstrate the safety and feasibility of IOHD in a cohort of critically ill patients with high MELD scores undergoing LT with good patient and renal outcomes.

The role of intraoperative hemodialysis in liver transplant patients.

PURPOSE OF REVIEW: Orthotopic liver transplant (OLT) is a major surgical procedure that can be both challenging and lengthy. One of the common findings in end-stage liver disease is renal failure, whether acute or chronic, which may complicate the intraoperative course. RECENT FINDINGS: The use of intraoperative hemodialysis is described by several centers to aid during OLT cases with impaired renal function or kidney failure. Unfortunately, there is a paucity of available data, which is limited to sporadic case reports, and only few structured studies in which continuous renal replacement therapy was used versus intraoperative hemodialysis, which is the main focus of this article. The rationale behind the use of intraoperative hemodialysis during OLT in patients with kidney dysfunction or failure is that the procedure is usually complicated by major hemodynamic changes, metabolic derangement, and coagulation abnormalities, which we think can be better managed intraoperatively using hemodialysis. In our institution, we performed over 140 cases of OLT using intraoperative hemodialysis since 2003 until the present. A retrospective cohort study is being conducted during the writing of this article. Preliminary data collection report zero percentage intraoperative mortality and 48 h postoperatively. SUMMARY: Hemodialysis is widely acknowledged as a treatment option to stabilize patients with renal failure, and one of the most challenging situations is during OLT in which the role of intraoperative hemodialysis is becoming more important today more than ever before.