Crystalloid flush with backward unclamping may decrease post-reperfusion cardiac arrest and improve short-term graft function when compared to portal blood flush with forward unclamping during liver transplantation

Anesthetic Considerations for Robotic Liver Transplantation

Liver transplantation has traditionally been performed through a large, bilateral subcostal incision. Recently, liver transplant programs across the world, including our own, have reported successful liver transplants via total robotic approaches on recipients with low Model for End-stage Liver Disease scores and preexisting abdominal wall laxity. This review discusses the unique anesthetic considerations of robotic liver transplantation based on our group's initial experience with this novel surgical approach. Robotic liver transplantation presents a unique set of considerations and challenges for the anesthesiologist, and a thorough understanding of liver disease, liver transplant surgery, venovenous bypass, and the various implications of robotic surgery is essential to ensure optimal patient outcomes. Specific management topics discussed here include appropriate patient selection, preoperative assessment, and intraoperative management. We also discuss certain theoretical and actual challenges that our group has experienced.

Postreperfusion Syndrome in Patients Receiving Vasoactive Drugs During Liver Graft Reperfusion

OBJECTIVES

The most widely used definition of postreperfusion syndrome in liver transplant is a 30% decrease in mean arterial pressure during the first 5 minutes after vascular unclamping. With these criteria, increased postoperative morbidity has been reported. Vasoactivedrugs couldpreventthis syndrome.Themain objective of our study was to determine the incidence and complications associated with postreperfusion syndrome inpatientswho receivedvasoactive support.

MATERIALS AND METHODS

We studied 246 patients who received norepinephrine infusions to maintain mean arterial pressure ≥60 mm Hg and who were monitored with a Swan-Ganz catheter. Patients received a bolus of adrenaline after vascular unclamping in cases of insufficient response to norepinephrine.

RESULTS

Among the study patients, 57 (23.17%) developed postreperfusion syndrome. Patients who developed postreperfusion syndrome did not present with morepostoperative complications interms ofrenal dysfunction (P = .69), repeat surgery (P = .15), graft rejection (P = .69), transplant replacement surgery (P = .76), hospital stay (P = .70), or survival (P = .17) compared with patients without postreperfusion syndrome.

CONCLUSIONS

In patients who underwent orthotopic liver transplant, in whom vasoactive drugs were administered, a diagnosis of self-limited postreperfusion syndrome during the first 5 minutes after unclamping may not be associated with postoperative complications. The administration of vasoconstrictors may have a preventive effect on the postoperative complications associated with postreperfusion syndrome or they may mask the real incidence of postreperfusion syndrome. A broader definition of postreperfusion syndrome should be accepted.

Bicarbonate ringer's solution could improve the intraoperative acid-base equilibrium and reduce hepatocellular enzyme levels after deceased donor liver transplantation: a randomized controlled study

BACKGROUND

Bicarbonate Ringer's (BR) solution is a direct liver and kidney metabolism-independent HCO3- buffering system. We hypothesized that BR solution would be more effective in improving acid-base equilibrium and more conducive to better liver function than Acetate Ringer's (AR) solution in conventional orthotopic liver transplantation (OLT) patients.

METHODS

Sixty-nine adult patients underwent OLT. Patients in the bicarbonate and acetate groups received BR solution or AR solution as infused crystalloids and graft washing solution, respectively. The primary outcome was the effect on pH and base excess (BE) levels. The secondary outcome measures were the incidence and volume of intraoperative 5% sodium bicarbonate infusion and laboratory indicates of liver and kidney function.

RESULTS

The pH and absolute BE values changed significantly during the anhepatic phase and immediately after transplanted liver reperfusion in the bicarbonate group compared with the acetate group (all P < 0.05). The incidence and volume of 5% sodium bicarbonate infusion were lower in the bicarbonate group than in the acetate group (all P < 0.05). The aspartate transaminase (AST) level at 7 postoperative days and the creatine level at 30 postoperative days were significantly higher in the acetate group than in the bicarbonate group (all P < 0.05).

CONCLUSION

Compared with AR solution, BR solution was associated with improved intraoperative acid-base balance and potentially protected early postoperative liver graft function and reduced late-postoperative renal injury.

Could retrograde reperfusion combined with washout technique broaden the applicability of marginal grafts in liver transplantation? Intra-operative and short-term outcomes of a prospective cohort

INTRODUCTION

many revascularization techniques were designed to reduce the imbalance of ischemia-reperfusion injury. This study's objective is to evaluate retrograde reperfusion (RR) compared to sequential anterograde reperfusion (AR), with and without the washout technique (WO).

METHOD

this prospective cohort study collected data from 94 deceased donor orthotopic liver transplants and divided it into three groups: RR with WO (RR+WO), AP with WO (AR+WO), and AP without WO (AR). This study did not assign the reperfusion technique to the participants. The primary outcome considered the early graft dysfunction, and secondary outcomes included post-reperfusion syndrome (PRS), post-reperfusion lactate, surgery fluid balance, and vasoactive drug dose during the surgery.

RESULTS

87 patients were submitted to the final analysis-29 in the RR+WO group, 27 in the AR+WO group, and 31 in the AR group. Marginal grafts prevalence was not significantly different between the groups (34% vs. 22% vs. 23%; p=0.49) and early graft dysfunction occurred at the same rate (24% vs. 26% vs. 19%; p=0.72). RR+WO reduced serum post-reperfusion lactate (p=0.034) and the incidence of significant PRS (17% vs. 33% vs. 55%; p=0.051), but norepinephrine dosing >0.5mcg/kg/min were not different during the surgery (20,7% vs. 29,6% vs. 35,5%, p=0.45).

CONCLUSIONS

primary outcome was not significantly different between the groups; however, intraoperative hemodynamic management was safer using the RR+WO technique. We theorized that the RR+WO technique could reduce the incidence of PRS and benefit marginal graft survival following diseased donor orthotopic liver transplantation.

Hypothermic Oxygenated Machine Perfusion (HOPE) Prior to Liver Transplantation Mitigates Post-Reperfusion Syndrome and Perioperative Electrolyte Shifts

(1) Background: Post-reperfusion syndrome (PRS) and electrolyte shifts (ES) represent considerable challenges during liver transplantation (LT) being associated with significant morbidity. We aimed to investigate the impact of hypothermic oxygenated machine perfusion (HOPE) on PRS and ES in LT. (2) Methods: In this retrospective study, we compared intraoperative parameters of 100 LTs, with 50 HOPE preconditioned liver grafts and 50 grafts stored in static cold storage (SCS). During reperfusion phase, prospectively registered serum parameters and vasopressor administration were analyzed. (3) Results: Twelve percent of patients developed PRS in the HOPE cohort vs. 42% in the SCS group (p = 0.0013). Total vasopressor demand in the first hour after reperfusion was lower after HOPE pretreatment, with reduced usage of norepinephrine (−26%; p = 0.122) and significant reduction of epinephrine consumption (−52%; p = 0.018). Serum potassium concentration dropped by a mean of 14.1% in transplantations after HOPE, compared to a slight decrease of 1% (p < 0.001) after SCS. The overall incidence of early allograft dysfunction (EAD) was reduced by 44% in the HOPE group (p = 0.04). (4) Conclusions: Pre-transplant graft preconditioning with HOPE results in higher hemodynamic stability during reperfusion and lower incidence of PRS and EAD. HOPE has the potential to mitigate ES by preventing hyperpotassemic complications that need to be addressed in LT with HOPE-pre-treated grafts.

Elevated effluent potassium concentrations predict the development of postreperfusion hyperkalemia in deceased liver transplantation: a retrospective cohort study

BACKGROUND

Postreperfusion hyperkalemia (PRHK) has garnered increasing attention in regard to deceased liver transplantation (LT), especially for LT using the expanded criteria donor grafts. However, the impact of the effluent potassium (eK⁺) concentration on PRHK has been largely overlooked. We evaluated whether elevated eK⁺ concentrations are associated with PRHK in deceased LT.

METHODS

In this single-institution, retrospective cohort study, we included all adults who underwent deceased LT with intraoperative eK⁺ concentration monitoring between November 2016 and December 2018. The eK⁺ concentrations were obtained from the effluent samples collected following a standard portal vein flush. PRHK was defined as any serum potassium (sK⁺) level of > 5.5 mmol/L following reperfusion. Logistic regression was performed to identify predictors for PRHK, and linear regression was used to examine predictors of the maximum percentage increase in the sK⁺ level following reperfusion.

RESULTS

Of the 86 patients who met the inclusion criteria, 54 (62.8%) developed PRHK. Independent predictors for PRHK included greater graft weight (OR 1.283 [95% CI 1.029-1.599] per 100 g, P = 0.027), an elevated eK⁺ concentration (OR 1.291 [95% CI 1.068-1.561] per mol/L, P = 0.008), and a higher sK⁺ level before reperfusion (OR 4.459 [95% CI 1.543-12.884] per mol/L, P = 0.006). An eK⁺ concentration of more than 6.9 mmol/L had a sensitivity of 59.26% and a specificity of 78.12% for predicting PRHK (area under the receiver operating characteristic curve, 0.694). Multiple linear regression analyses indicated that the eK⁺ and sK⁺ levels before reperfusion were significant predictors of the maximum percentage increase in the sK⁺ level following reperfusion. In addition, PRHK was associated with an increased risk of postreperfusion significant arrhythmias, severe postreperfusion syndrome, and postoperative early allograft dysfunction.

CONCLUSIONS

This study shows that the eK⁺ concentration could predict the risk of PRHK in deceased LT. Further prospective studies are warranted to clarify these associations.

Primary liver graft dysfunction and non-function: integrative literature review

Avoiding deaths in the waiting list for an organ is no longer the only focus of the transplant teams attention. Research and care in clinical practice has been increasingly focused on post transplant graft survival and functioning. In the present work, we performed an integrative literature review to identify the terminology used about liver graft dysfunction and non-function, as well as to investigate the incidence and risk factors of these clinical events. We chosen articles written in Portuguese, English and Spanish between 2012 and 2016, based on CINAHL, MEDLINE, Cochrane, LILACS, BDENF, IBECS, EMBASE and Web of Science. We selected 14 studies, in which we identified the incidence of hepatic graft dysfunction ranging from 7% to 27%. The terminology used to describe this clinical event was initial malfunction, graft hypofunction, marginal function or delay in function. The primary non-function of the liver graft was found in 1.4% to 8.4% of the patients, and the terminology used to describe the event was early dysfunction or graft loss. The risk factors found are related to donor, recipient, graft and transplant logistics variables. We conclude that knowledge of the different terminologies employed in the literature, related to dysfunction and primary non- function incidence, and of their risk factors are fundamental to qualify the control of the events, aiming to improve patients' survival after liver transplantation.

Expanded Criteria Donor-Related Hyperkalemia and Postreperfusion Cardiac Arrest During Liver Transplantation: A Case Report and Literature Review

Background

Liver transplantation (LT) using extended criteria donor (ECD) grafts is frequently associated with a high flush fluid potassium concentration (FFK) and acute hyperkalemia after reperfusion, which puts patients at greater risk of postreperfusion cardiac arrest (PRCA).

Case Report

Herein, we present a case with an extremely high FFK that was successfully pretreated to avoid the risk of PRCA. A 3-year-old boy with biliary atresia underwent LT from a 623-g donation after brain death liver graft with localized frostbite on the right lobe surface. The FFK was 18.8 mmol/L after flushing with 1000 mL of 5% albumin. To prevent PRCA due to acute hyperkalemia, further portal vein (PV) flush, retrograde reperfusion via the inferior vena cava, and antegrade reperfusion via the PV were adopted to remove the excessive potassium ions. Ultimately, the liver graft was reperfused when the perfused blood potassium concentration was 7.5 mmol/L without subsequent development of PRCA during the immediate reperfusion period. Nevertheless, the patient still experienced vasoplegic syndrome during the late reperfusion period.

Conclusions

Our case illustrates that the FFK measurement is helpful for identifying ECD-related hyperkalemia and for providing advance warning of PRCA. Future investigations are warranted to confirm the relationship between high FFK and PRCA and to observe the effectiveness of other interventions to prevent PRCA due to ECD-related hyperkalemia.

The Impact of Implantation Time During Liver Transplantation on Outcome: A Eurotransplant Cohort Study

Supplemental digital content is available in the text.

Background

The liver graft quickly rewarms during transplantation when the vascular anastomoses are being performed, potentially impacting on outcomes.

Methods

We investigated the relationship between implantation time and outcome in 5223 recipients of deceased-donor livers transplanted in Eurotransplant (2004-2013). Cox regression analyses were corrected for donor, preservation, and recipient variables. Transplant loss represents all-cause graft failure.

Results

Median implantation time was 41 minutes (interquartile range, 34-51). Implantation time independently associated with transplant loss (adjusted hazard ratio, 1.04 for every 10-minute increase; 95% confidence interval, 1.01-1.07; P = 0.007). The magnitude of the implantation time effect was comparable to the effect of each additional hour of cold ischemia (adjusted hazard ratio, 1.03; 95% confidence interval, 1.02-1.05; P < 0.001). The effect was most pronounced early posttransplant with no evidence of a significant effect beyond 3 months. A similar detrimental effect of implantation time was seen for graft and patient survivals. The increased risk for transplant loss in livers donated after circulatory determination of death could be attributed to donor warm ischemia time.

Conclusions

Implantation time associates with inferior liver transplant outcome in a continuous way. These findings need confirmation and further study of confounding factors is needed so steps toward improving outcomes can be made.

Association Between Flushed Fluid Potassium Concentration and Severe Postreperfusion Syndrome in Deceased Donor Liver Transplantation

Backgrounds

Predicting the occurrence of severe postreperfusion syndrome (PRS) is clinically challenging. We investigated whether the flushed fluid potassium concentration (FFK) was associated with severe PRS in deceased donor liver transplantation (DDLT).

Material/Methods

Forty adult DDLT recipients were enrolled in this retrospective study. Effluent solution samples were collected at the end of the portal vein flush, and the FFK was determined using a point-of-care blood gas analyzer. The risk factors associated with severe PRS and the clinical outcomes in 2 groups were compared.

Results

Severe PRS occurred in 22 out of 40 patients (55.0%). The FFK of the severe PRS group was significantly higher than that of the non-severe PRS group (median, 9.6 vs. 5.8, P<0.001). Other variables associated with severe PRS included the donor risk index (DRI), Child-Turcotte-Pugh score, donor type, donor warm ischemia time, and Model for End-stage Liver Disease score. The area under the receiver operator characteristic curve for the FFK was 0.982, and the best cut-off value of the FFK for predicting severe PRS was 6.75 mmol/L (100.0% sensitivity and 88.9% specificity). A significant positive correlation was observed between the FFK and DRI (R=0.714). Patients who experienced severe PRS had a higher early allograft dysfunction rate (63.6% vs. 22.2%, P=0.019) and a longer hospital stay (median, 33.0 vs. 24.0, P=0.034).

Conclusions

Both the severity of the recipient’s liver disease and the donor graft factors play an important role in the development of severe PRS in DDLT. An FFK of more than 6.75 mmol/L was associated with severe PRS after reperfusion.

Short-term effects of extracorporeal graft rinse versus circulatory graft rinse in living donor liver transplantation. A prospective randomized controlled trial

Living donor liver transplantation has shorter cold ischemia time, less preservative volume, and lower metabolic load compared to transplantation from deceased donors. We investigated the impact of rinsing the graft contents into the systemic circulation on operative course and postoperative outcomes. Donors had right hepatectomy, and grafts were preserved with cold histidine-tryptophan-ketoglutarate solution. On ending portal vein anastomosis, grafts were flushed by patient's portal blood either through incompletely anastomosed hepatic vein (extracorporeal rinse group, EcRg, n = 40) or into systemic circulation (circulatory rinse group, CRg, n = 40). The primary outcome objective was the lowest mean arterial blood pressure within 5 min after portal unclamping as a marker for postreperfusion syndrome (PRS). Secondary objectives included hemodynamics and early graft's and patient's outcomes. Within 5 min postreperfusion, mean arterial blood pressure was significantly lower in the CRg compared to the EcRg, yet this was clinically insignificant. Postoperative graft functions, early biliary and vascular complications, and three-month survival were comparable in both groups. Rinsing the graft into the circulation increased the incidence of PRS without significant impact on early graft or patient outcome in relatively healthy recipients.

Post reperfusion syndrome during liver transplantation: From pathophysiology to therapy and preventive strategies

This review aims at evaluating the existing evidence regarding post reperfusion syndrome, providing a description of the pathophysiologic mechanisms involved and possible management and preventive strategies. A PubMed search was conducted using the MeSH database, “Reperfusion” AND “liver transplantation” were the combined MeSH headings; EMBASE and the Cochrane library were also searched using the same terms. 52 relevant studies and one ongoing trial were found. The concept of post reperfusion syndrome has evolved through years to a multisystemic disorder. The implications of the main organ, recipient and procedure related factors in the genesis of this complex syndrome are discussed in the text as the novel pharmacologic and technical approaches to reduce its incidence. However the available evidence about risk factors, physiopathology and preventive measures is still confusing, the presence of two main definitions and the numerosity of possible confounding factors greatly complicates the interpretation of the studies.

Arrhythmogenic potential develops rapidly at graft reperfusion before the start of hypotension during living-donor liver transplantation

Background

Detailed profiles of acute hypothermia and electrocardiographic (ECG) manifestations of arrhythmogenicity were examined to analyze acute hypothermia and ventricular arrhythmogenic potential immediately after portal vein unclamping (PVU) in living-donor liver transplantation (LT).

Methods

We retrospectively analyzed electronically archived medical records (n = 148) of beat-to-beat ECG, arterial pressure waveforms, and blood temperature (BT) from Swan-Ganz catheters in patients undergoing living-donor LT. The ECG data analyzed were selected from the start of BT drop to the initiation of systolic hypotension after PVU.

Results

On reperfusion, acute hypothermia of < 34℃, < 33℃ and < 32℃ developed in 75.0%, 37.2% and 11.5% of patients, respectively. BT decreased from 35.0℃ ± 0.8℃ to 33.3℃ ± 1.0℃ (range 35.8℃–30.5℃). The median time to nadir of BT was 10 s after PVU. Difference in BT (ΔBT) was weakly correlated with graft-recipient weight ratio (GRWR; r = 0.22, P = 0.008). Compared to baseline, arrhythmogenicity indices such as corrected QT (QTc), Tp-e (T wave peak to end) interval, and Tp-e/QTc ratio were prolonged (P < 0.001 each). ST height decreased and T amplitude increased (P < 0.001 each). However, no correlation was found between ΔBT and arrhythmogenic indices.

Conclusions

In living-donor LT, regardless of extent of BT drop, ventricular arrhythmogenic potential developed immediately after PVU prior to occurrence of systolic hypotension.