Intraoperative continuous renal replacement therapy during liver transplantation: a pilot randomized-controlled trial (INCEPTION)

Intraoperative kidney replacement therapy in acute liver failure

Paediatric acute liver failure (PALF) is often characterised by its rapidity of onset and potential for significant morbidity and even mortality. Patients often develop multiorgan dysfunction/failure, including severe acute kidney injury (AKI). Whilst the management of PALF focuses on complications of hepatic dysfunction, the associated kidney impairment can significantly affect patient outcomes. Severe AKI requiring continuous kidney replacement therapy (CKRT) is a common complication of both PALF and liver transplantation. In both scenarios, the need for CKRT is a poor prognostic indicator. In adults, AKI has been shown to complicate ALF in 25-50% of cases. In PALF, the incidence of AKI is often higher compared to other critically ill paediatric ICU populations, with reports of up to 40% in some observational studies. Furthermore, those presenting with AKI regularly have a more severe grade of PALF at presentation. Observational studies in the paediatric population corroborate this, though data are not as robust-mainly reflecting single-centre cohorts. Perioperative benefits of CKRT include helping to clear water-soluble toxins such as ammonia, balancing electrolytes, preventing fluid overload, and managing raised intracranial pressure. As liver transplantation often takes 6-10 h, it is proposed that these benefits could be extended to the intraoperative period, avoiding any hiatus. Intraoperative CKRT (IoCKRT) has been shown to be practicable, safe and may help sicker recipients tolerate the operation with outcomes analogous with less ill patients not requiring IoCKRT. Here, we provide a comprehensive guide describing the rationale, practicalities, and current evidence base surrounding IoCKRT during transplantation in the paediatric population.

Liver Transplantation in Acute-on-Chronic Liver Failure

In recent years there has been a significant increase in the incidence of acute-on-chronic liver failure (ACLF). This syndrome is characterized by infections, organ failures, and high short-term mortality. Although progress in the management of these sick patients has been evident, liver transplantation (LT) remains the best treatment modality to date. Several studies have reported LT as a feasible option, despite organ failures. The outcomes following LT are inversely related to the grade of ACLF. This review discusses the current literature on the feasibility, futility, timing, and outcomes of LT in patients with ACLF.

Intraoperative Renal Replacement Therapy in Orthotopic Liver Transplantation

Acute kidney injury in patients admitted to the hospital for liver transplantation is common, with up to 80% of pretransplant patients having some form of acute kidney injury. Many of these patients start on dialysis prior to their transplant and have it continued intraoperatively during their surgery. This review discusses the limited existing literature and expert opinion around the indications and outcomes around intraoperative dialysis (intraoperative renal replacement therapy) during liver transplantation. More specifically, we discuss which patients may benefit from intraoperative renal replacement therapy and the impact of hyponatremia and hyperammonemia on the dialysis prescription. Additionally, we discuss the complex interplay between anesthesia and intraoperative renal replacement therapy and how the need for clearance and ultrafiltration changes throughout the different phases of the transplant (preanhepatic, anhepatic, and postanhepatic). Lastly, this review will cover the limited data around patient outcomes following intraoperative renal replacement therapy during liver transplantation as well as the best evidence for when to stop dialysis.

Management of the acute on chronic liver failure in the intensive care unit

Acute on chronic liver failure (ACLF) reflects the development of organ failure(s) in a patient with cirrhosis and is associated with high short-term mortality. Given that ACLF has many different 'phenotypes', medical management needs to take into account the relationship between precipitating insult, organ systems involved and underlying physiology of chronic liver disease/cirrhosis. The goals of intensive care management of patients suffering ACLF are to rapidly recognize and treat inciting events (e.g. infection, severe alcoholic hepatitis and bleeding) and to aggressively support failing organ systems to ensure that patients may successfully undergo liver transplantation or recovery. Management of these patients is complex since they are prone to develop new organ failures and infectious or bleeding complications. ICU therapy parallels that applied in the general ICU population in some complications but differs in others. Given that liver transplantation in ACLF is an emerging and evolving field, multidisciplinary teams with expertise in critical care and transplant medicine best accomplish management of the critically ill ACLF patient. The focus of this review is to identify the common complications of ACLF and to describe the proper management in critically ill patients awaiting liver transplantation in our centres, including organ support, prognostic assessment and how to assess when recovery is unlikely.

Chronic Kidney Disease After Liver Transplantation

Improved survival after liver transplantation has led to an aging cohort of recipients at risk of renal dysfunction. The etiology of renal dysfunction is typically multifactorial; calcineurin inhibitors nephrotoxicity, pretransplant renal dysfunction, and perioperative acute kidney injury are important risk factors. Metabolic complications such as hypertension, diabetes mellitus, and metabolic-associated fatty liver disease also contribute to the development of renal disease. Most LT recipients will eventually develop some degree of renal dysfunction. Criteria to select candidates for simultaneous liver and kidney transplantation have been established. Both delayed introduction of CNIs and renal-sparing immunosuppressive regimens may reduce progression of renal dysfunction.

Post-Liver Transplant Acute Kidney Injury

Acute kidney injury (AKI) is a common condition following liver transplantation (LT). It negatively impacts patient outcomes by increasing the chances of developing chronic kidney disease and reducing graft and patient survival rates. Multiple definitions of AKI have been proposed and used throughout the years, with the International Club of Ascites definition being the most widely now used for patients with cirrhosis. Multiple factors are associated with the development of post-LT AKI and can be categorized into pre-LT comorbidities, donor and recipient characteristics, operative factors, and post-LT factors. Many of these factors can be optimized in an attempt to minimize the risk of AKI occurring and to improve renal function if AKI is already present. A special consideration during the post-LT phase is needed for immunosuppression as certain immunosuppressive medications can be nephrotoxic. The calcineurin inhibitor tacrolimus (TAC) is the mainstay of immunosuppression but can result in AKI. Several strategies including use of the monoclonoal antibody basilixamab to allow for delayed initiation of tacrolimus therapy and minimization through combination and minimization or elimination of TAC through combination with mycophenolate mofetil or mammalian target of rapamycin inhibitors have been implemented to reverse and avoid AKI in the post-LT setting. Renal replacement therapy may ultimately be required to support patients until recovery of AKI after LT. Overall, by improving renal function in post-LT patients with AKI, outcomes can be improved.

Intraoperative Renal Replacement Therapy: Practical Information for Anesthesiologists

Previous publications regarding perioperative renal replacement therapy (RRT) have focused on the general care of the RRT-dependent patient and provided a broad overview of the various RRT modalities. The goal of this review article is to provide anesthesiologists with specific practical information regarding the possible intraoperative advantages and limitations of each modality, mandatory equipment to institute intraoperative therapy, and background knowledge necessary to communicate effectively with nephrologists and/or support staff regarding the intraoperative RRT goals.

Liver Transplantation in Acute-on-chronic Liver Failure

Liver transplantation (LT) has revolutionized outcomes for cirrhotic patients. Current liver allocation policies dictate patients with highest short-term mortality receive the highest priority, thus, several patients become increasingly ill on the waitlist. Given cirrhosis is a progressive disease, it can be complicated by the occurrence of acute-on-chronic liver failure (ACLF), a syndrome defined by an acute deterioration of liver function associated with extrahepatic organ failures requiring intensive care support and a high short-term mortality. Successfully bridging to transplant includes accurate prognostication and prioritization of ACLF patients awaiting LT, optimizing intensive care support pre-LT, and tailoring immunosuppressive and anti-infective therapies post-LT. Furthermore, predicting futility (too sick to undergo LT) in ACLF is challenging. In this review, we summarize the role of LT in ACLF specifically highlighting (a) current prognostic scores in ACLF, (b) critical care management of the ACLF patient awaiting LT, (c) donor issues to consider in transplant in ACLF, and (d) exploring of recent post-LT outcomes in ACLF and potential opportunities to improve outcomes including current care gaps and unmet research needs.

Hepatorenal Syndrome

Development of acute kidney injury in patients with chronic liver disease is common and portends a poor prognosis. Diagnosis remains challenging, as traditional markers, such as serum creatinine, are not reliable. Recent development of novel biomarkers may assist with this. Pathophysiology of this condition is multifactorial, relating to physiologic changes associated with portal hypertension, kidney factors, and systemic inflammatory response. Mainstay of treatment remains use of vasoconstrictors along with albumin. Recent guidelines streamline the selection of patients that will require simultaneous liver and kidney transplantation. Posttransplant kidney injury is common relating to multiple factors.

Acute-on-chronic liver failure: Definitions, pathophysiology and principles of treatment

The term acute-on-chronic liver failure (ACLF) defines an abrupt and life-threatening worsening of clinical conditions in patients with cirrhosis or chronic liver disease. In recent years, different definitions and diagnostic criteria for the syndrome have been proposed by the major international scientific societies. The main controversies relate to the type of acute insult (specifically hepatic or also extrahepatic), the stage of underlying liver disease (cirrhosis or chronic hepatitis) and the concomitant extrahepatic organ failure(s) that should be considered in the definition of ACLF. Therefore, different severity criteria and prognostic scores have been proposed and validated. Current evidence shows that the pathophysiology of ACLF is closely associated with an intense systemic inflammation sustained by circulating pathogen-associated molecular patterns and damage-associated molecular patterns. The development of organ failures may be a result of a combination of tissue hypoperfusion, direct immune-mediated damage and mitochondrial dysfunction. Management of ACLF is currently based on the supportive treatment of organ failures, mainly in an intensive care setting. For selected patients, liver transplantation is an effective treatment that offers a good long-term prognosis. Future studies on potential mechanistic treatments that improve patient survival are eagerly awaited.

Intraoperative Continuous Renal Replacement Therapy During Liver Transplantation: A Meta-Analysis

Continuous renal replacement therapy (CRRT) is frequently used to treat recipients with renal failure before or after liver transplantation (LT), though evidence supporting its use during surgery remains unclear. Therefore, we conducted a quantitative meta-analysis to evaluate the effect of intraoperative continuous renal replacement therapy (IORRT) in recipients with pretransplant severe renal dysfunction. We searched PubMed, Embase, and the Cochrane database for trials focusing on LT recipients supported with or without IORRT. Outcomes assessed were mortality, preoperative characteristics, intraoperative data, and predefined postoperative outcomes. Seven trials with 1051 recipients were eligible. Preoperatively, the IORRT group recipients had higher Model for End-Stage Liver Disease scores (weighted mean difference [WMD], 6.19; 95% confidence interval [CI], 2.51-9.87), Charlson scores (WMD, 0.45; 95% CI, 0.09-0.80), acute liver failure (odds ratio [OR], 1.82; 95% CI, 1.27-2.61), serum creatinine (WMD, 71.33 μmol/L; 95% CI, 1.98-140.69 μmol/L), total bilirubin level (WMD, 5.05 μmol/L; 95% CI, 1.75-8.35 μmol/L), intensive care unit admission (OR, 3.53; 95% CI, 1.23-10.13), vasoactive therapy (OR, 3.80; 95% CI, 2.64-5.46), ventilator care (OR, 2.52; 95% CI, 1.18-5.35), and renal replacement therapy (RRT) (OR, 29.37; 95% CI, 7.66-112.54) compared with control patients. IORRT patients also required more intraoperative blood product transfusion and had more post-LT RRT (OR, 25.67; 95% CI, 4.92-133.85). However, there were no significant differences in short-term mortality (OR, 2.12; 95% CI, 0.82-5.44) between the groups. In addition, worse longterm mortality was seen in the IORRT group. In conclusion, IORRT is feasible and safe and may help sicker recipients tolerate the LT procedure to achieve short-term clinical outcomes comparable with less ill patients without IORRT. More high-quality evidence is needed to verify our conclusion in the future.

Intraoperative Dialysis During Liver Transplantation

BACKGROUND

Orthotopic liver transplantation (LT) is a technically complex surgical procedure associated with a major risk of hemodynamic instability and metabolic derangement, especially in patients with coexisting renal dysfunction. Some centers have applied intraoperative renal replacement therapy (ioRRT) to support patients with preoperative renal failure and prevent critical complications. Although there is a strong theoretical rationale for this treatment, there remains a paucity of definite data demonstrating its benefits.

METHODS

This was a retrospective observational study of all adult patients undergoing intraoperative dialysis in our center from January 2010 till December 2016.

RESULTS

The study group consisted of 88 patients with a mean MELD score of 31.4. Six patients underwent simultaneous liver and kidney transplantation. Forty-four (50%) recipients were admitted to the intensive care unit before transplantation, and 19 (21.6%) needed mechanical ventilation. Twenty-eight (31.8%) of the procedures were retransplantations, and 40 (45.4%) patients had been undergoing renal replacement therapy before LT. The mean preoperative serum creatinine was 2.82 ± 1.13 mg/dL. The majority of patients (54.5%) was operated on using the veno-venous bypass technique. The mean arterial blood pH and potassium levels after reperfusion were 7.2 ± 0.12 and 4.04 ± 0.95 mmol/L, respectively. Postreperfusion syndrome (PRS) occurred in 11 (13.9%) patients in whom dialysis started at least 15 minutes before reperfusion. Dialysis circuit clotting occurred in 9.1% of cases. There were no other adverse events of ioRRT.

CONCLUSION

Our data suggests that intraoperative dialysis in severely ill patients with a high MELD score is safe and effective. Lower than expected PRS occurrence needs to be confirmed in a study with a control group.

Acute kidney injury: A critical care perspective for orthotopic liver transplantation

Acute kidney injury (AKI) is associated with high perioperative mortality in patients undergoing liver transplantation (LT). In the era of Model of End-stage Liver Disease score-based allocation, more patients with impaired renal function are receiving LT. The majority of preoperative AKI is secondary to azotemia, including hepatorenal syndrome - a progressive form of renal impairment unique to liver failure. Prompt recognition and initiation of cause-directed therapies are central to improving post-transplant survival. Given that, the healthcare providers must develop an expertise in liver failure-related renal complications, specifically their management and perioperative implications. Notably, AKI may complicate intraoperative course, exacerbating hemodynamic instability, metabolic acidosis, and electrolyte and coagulation abnormalities. Adjunctive intraoperative continuous renal replacement therapy has been employed; however, prospective studies remain necessary to validate potential benefits.