Benefits of Intraoperative Continuous Renal Replacement Therapy During Liver Transplantation in Patients With Renal Dysfunction

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.

Successful use of intra-operative continuous renal replacement therapy in pediatric liver transplant recipients: Single center case series

BACKGROUND

Acute kidney injury (AKI) is common in pediatric patients undergoing liver transplantation (LT), with an incidence 17%-55%. Fluid, metabolic, and acid-base aberrancies are often pronounced pre-operatively and further worsened by events during LT, making intra-operative continuous renal replacement therapy (CRRT) an option for critically ill LT recipients.

METHODS

All pediatric LT performed at our institution who underwent intra-operative CRRT between January 2017 and August 2021 were included. Patient demographics and clinical data including graft outcomes, intra-operative findings, and timing and indications for CRRT were collected from the electronic medical record.

RESULTS

CRRT was used in nine of the 76 (12%) pediatric LT performed at our center during the study period. Ages at LT ranged from 39 to 17.7 years. Recipients requiring CRRT were more likely to have acute liver failure, status 1A, and higher calculated MELD/PELD scores. CRRT was initiated pre-transplant in three recipients and continued post-transplant in six recipients. Median duration of CRRT was two (range 0-14) days. Indications included hyperammonemia (3/9), acidosis (3/9), fluid overload (6/9), and hyperkalemia (2/9). The CRRT group had a significantly longer post-transplant intensive care unit length of stay in comparison to those that did not require CRRT (median 6, range 3-40 days vs. median 3, range 0-121 days, p = .02], but there were no significant differences in reoperations, hospital length of stay, or recipient or graft survival.

CONCLUSIONS

We demonstrate that CRRT can be safely performed in pediatric LT recipients, including young infants through adolescents.

Intraoperative dialysis with the use of a mobile dialysis system during liver transplantation

PURPOSE

Over the last few years, transplant centers have started to use various intraoperative renal replacement therapy (ioRRT) modalities during liver transplantation (LT) in patients with pre-existing renal impairment. Here, we present a study on the safety and clinical outcomes of intraoperative hemodialysis (ioHD) performed using a mobile dialysis system during LT.

PATIENTS AND METHODS

We retrospectively analyzed 102 adult patients undergoing LT with ioHD; pre-existing renal failure and/or intraoperative metabolic derangement were ioHD treatment indications.

RESULTS

Our study cohort consisted of three groups: LT with preoperative serum creatinine (sCr) ​< ​2 ​mg/dL (Group 1:n ​= ​22), LT with preoperative sCr ≥2 ​mg/dL (Group 2:n ​= ​73), and simultaneous liver-kidney transplantation (Group 3:n ​= ​7). Among the procedures, 30% were re-transplantations. The mean calculated Model for End-stage Liver Disease score in Group 2 was 39.2, and 67% of patients were hospitalized in the intensive care unit. Patients in Group 1 were less acutely ill but developed severe intraoperative derangements and, therefore, underwent urgent ioHD intraoperatively. However, it was delayed when compared to Group 2. All groups achieved post-reperfusion potassium levels <4 ​mmol/L and a decrease in central venous pressure. No serious procedural complications occurred. Post-reperfusion syndrome occurred in 12.7% of patients. Elevated mortality was likely due to the high illness severity in the cohort.

CONCLUSIONS

Performing ioHD with a mobile dialysis system during LT was safe and effective, while being easier to perform than continuous techniques. Its effect on intra- and postoperative outcomes should be addressed in a study with a control group.

Peritransplant Renal Dysfunction in Liver Transplant Candidates

Renal function is intricately tied to Model for End-Stage Liver Disease score and overall prognosis among patients with cirrhosis. The estimation of glomerular filtration rate (GFR) and etiology of renal impairment are even more magnified among cirrhotic patients in the period surrounding liver transplantation. Novel biomarkers including cystatin C and urinary neutrophil gelatinase-associated lipocalin have been demonstrated to more accurately assess renal dysfunction and aid in the diagnosis of competing etiologies. Accurately identifying the severity and chronicity of renal dysfunction among transplant candidates is an imperative component with respect to stratifying patients toward simultaneous liver-kidney transplantation versus liver transplantation alone.

Hyponatremia and Liver Transplantation: A Narrative Review

Hyponatremia is a common electrolyte disorder in patients with end-stage liver disease (ESLD) and is associated with increased mortality on the liver transplantation (LT) waiting list. The impact of hyponatremia on outcomes after LT is unclear. Ninety-day and one-year mortality may be increased, but the data are conflicting. Hyponatremic patients have an increased rate of complications and longer hospital stays after transplant. Although rare, osmotic demyelination syndrome (ODS) is a feared complication after LT in the hyponatremic patient. The condition may occur when the serum sodium (sNa) concentration increases excessively during or after LT. This increase in sNa concentration correlates with the degree of preoperative hyponatremia, the amount of intraoperative blood loss, and the volume of intravenous fluid administration. The risk of developing ODS after LT can be mitigated by avoiding large perioperative increases in sNa concentration . This can be achieved through measures such as carefully increasing the sNa pretransplant, and by limiting the intravenous intra- and postoperative amounts of sodium infused. SNa concentrations should be monitored regularly throughout the entire perioperative period.

Anesthesia for Combined Heart and Liver Transplantation

A heart or liver transplantation procedure performed in isolation itself presents multiple challenges for the perioperative team. Accordingly, combining both transplants yields a vastly more complicated surgery, with many unique multisystem and multidisciplinary considerations. Although combined heart and liver transplantations are being performed with increasing frequency, nationwide experience is relatively limited at most institutions. The aim of this review is to discuss the perioperative challenges presented to the anesthesiology teams and provide evidence-based guidance for the management of these daunting procedures.

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.

Peri-transplant renal dysfunction in patients with non-alcoholic steatohepatitis undergoing liver transplantation

Non-alcoholic fatty liver disease (NAFLD) is currently the most common etiology of chronic liver disease (CLD) caused by an accumulation of fat in the liver and globally is the leading indication of liver transplantation. Emerging data has recognized an increased association of NAFLD with risk of other metabolic liver diseases like type 2 diabetes mellitus, chronic kidney disease (CKD) and cardiovascular diseases. Pathophysiologically, NAFLD patients have a state of low-grade systemic inflammation, insulin resistance and atherogenic dyslipidemia which causes renal dysfunction. Patients with NAFLD cirrhosis awaiting liver transplant (LT) face unique challenges and have a significantly higher requirement of simultaneous-liver-kidney transplant as compared to other etiologies. Further, NAFLD not only recurs but also occurs as a de novo manifestation post-LT. There is also a significantly higher risk of waiting list stagnation and dropouts due to burdensome cardiometabolic disorders in NAFLD patients. The current review aims to understand the prevalence and pathogenetic basis of renal dysfunction in NAFLD. Additionally, the review describes the choice of immunosuppression protocols and use of intraoperative renal replacement therapy in context of intra and post-operative renal dysfunction in NAFLD patients. Prospective controlled trials focusing on NAFLD and development of CKD are needed to assess the existence of a causal and/or a bidirectional relationship between NAFLD and CKD.

2019 Clinical Update in Liver Transplantation

Liver transplantation continues be the standard for treatment of end-stage liver disease, and even with recent advances in organ preservation, the anesthetic management continues to require understanding of multiple organ systems beyond the liver. Multiple factors contribute to hemodynamic changes after reperfusion of the liver graft that anesthesiologists should be aware of before unclamping. Concomitant renal dysfunction in end-stage liver disease is not uncommon, and preparation for continuous renal replacement therapy may need to be considered in certain cases. Cardiac evaluation of liver transplantation patients with an emphasis on arrhythmias, including atrial fibrillation, can help prevent both intraoperative and postoperative complications detrimental to the patient and graft. Finally, combined liver and thoracic organ transplantations may be indicated for certain disease processes that affect multiple organs. These cases require an understanding of the surgical technique and acknowledgment that some goals of the procedures may be in direct opposition to each other.

Predictive utility of the C-reactive protein to albumin ratio in early allograft dysfunction in living donor liver transplantation: A retrospective observational cohort study

BACKGROUND

This study was performed to determine the association between the ratio of C-reactive protein to albumin (CRP/ALB) and the risk of early allograft dysfunction (EAD) in patients undergoing living donor liver transplantation (LDLT).

PATIENTS AND METHODS

A total of 588 adult patients undergoing LDLT were retrospectively investigated, after 22 were excluded because of signs of overt infection or history of ALB infusion. The study population was classified into high and low CRP/ALB ratio groups according to EAD. All laboratory variables, including CRP and ALB, had been collected on the day before surgery. A percentage value for the CRP/ALB ratio (%) was calculated as CRP/ALB × 100.

RESULTS

After LDLT, 83 patients (14.1%) suffered EAD occurrence. A higher CRP/ALB ratio was independently associated with risk of EAD, Model for End-stage Liver Disease score, fresh frozen plasma transfusion, and donor age. Based on a cutoff CRP/ALB ratio (i.e., > 20%), the probability of EAD was significantly (2-fold) higher in the high versus low CRP/ALB group. The predictive utility of CRP/ALB ratio for EAD was greater than those of other inflammatory markers. In addition, patients with a high CRP/ALB ratio had poorer survival than those with a low CRP/ALB ratio during the follow-up period.

CONCLUSIONS

The easily calculated CRP/ALB ratio may allow estimation of the risk of EAD after LDLT and can provide additional information that may facilitate the estimation of a patient's overall condition.

Analysis of pre- and intraoperative clinical for successful operating room extubation after living donor liver transplantation: a retrospective observational cohort study

BACKGROUND

Early extubation after liver transplantation is safe and accelerates patient recovery. Patients with end-stage liver disease undergo sarcopenic changes, and sarcopenia is associated with postoperative morbidity and mortality. We investigated the impact of core muscle mass on the feasibility of immediate extubation in the operating room (OR) after living donor liver transplantation (LDLT).

METHODS

A total of 295 male adult LDLT patients were retrospectively reviewed between January 2011 and December 2017. In total, 40 patients were excluded due to emergency surgery or severe encephalopathy. A total of 255 male LDLT patients were analyzed in this study. According to the OR extubation criteria, the study population was classified into immediate and conventional extubation groups (39.6 vs. 60.4%). Psoas muscle area was estimated using abdominal computed tomography and normalized by height squared (psoas muscle index [PMI]).

RESULTS

There were no significant differences in OR extubation rates among the five attending transplant anesthesiologists. The preoperative PMI correlated with respiratory performance. The preoperative PMI was higher in the immediate extubation group than in the conventional extubation group. Potentially significant perioperative factors in the univariate analysis were entered into a multivariate analysis, in which preoperative PMI and intraoperative factors (i.e., continuous renal replacement therapy, significant post-reperfusion syndrome, and fresh frozen plasma transfusion) were associated with OR extubation. The duration of ventilator support and length of intensive care unit stay were shorter in the immediate extubation group than in the conventional extubation group, and the incidence of pneumonia and early allograft dysfunction were also lower in the immediate extubation group.

CONCLUSIONS

Our study could improve the accuracy of predictions concerning immediate post-transplant extubation in the OR by introducing preoperative PMI into predictive models for patients who underwent elective LDLT.

Long-term impact of dialysis-requiring AKI during the perioperative period of liver transplantation on postdischarge outcomes

BACKGROUND

Patients undergoing liver transplantation (LT) are prone to dialysis-requiring acute kidney injury (AKI-D). However, long-term prognoses among them need further investigation, as overall survival after LT is improving.

METHODS

A nationwide, population-based cohort study was conducted using the data of Korean National Health Insurance System between 2006 and 2015. The patients who received dialysis during the perioperative period of LT were in the AKI-D group, and the control group included those who did not undergo dialysis.

RESULTS

Among the 6879 patients who underwent LT, 968 were in the AKI-D group. All-cause mortality [adjusted hazard ratio (HR): 1.52 (1.26-1.83), P < 0.001], end-stage renal disease (ESRD) progression [adjusted HR: 2.93 (2.34-3.66), P < 0.001], and ICU readmission [adjusted HR: 1.70 (1.44-2.01), P < 0.001] within and after 90 days from discharge were increased in the AKI-D group. When analyzed among those who recovered from dialysis at discharge, overall outcomes were similar to those of the AKI-D group, except the long-term mortality.

CONCLUSIONS

AKI-D during the perioperative period of LT was associated with worse mortality, ESRD progression, and ICU readmission risk. The results of renal-recovered patients could indicate clinicians that achievement of dialysis independence is important to gain favorable long-term postdischarge survival.