The Minimal Flush Volume for Washout of Preservation Fluid in Liver Transplantation

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.

Changes in Blood Potassium after Reperfusion during Living-Donor Liver Transplantation: An Exploratory Study

The incidence of hyperkalemia (>5.5 mEq/L) or high blood potassium (5–5.5 mEq/L) during living-donor liver transplantation (LDLT) is reported to be more than 10%. It occurs more frequently in the early post-reperfusion period and is a major cause of post-reperfusion arrhythmia and cardiac arrest. Unlike deceased-donor liver transplantation, the pattern of blood potassium changes immediately after reperfusion has not been described in LDLT. From January 2021 to March 2021, fifteen consecutive patients were enrolled. Baseline blood potassium was measured from blood samples obtained 10-min (T_-10) and immediately before (T₀) reperfusion. During the first 5 min after reperfusion, blood potassium measurements were conducted every one minute (T₁–T₅). The blood potassium levels at T_-10 and T₀ were 3.8 ± 0.4 and 3.9 ± 0.4 mEq/L, respectively. After reperfusion, mean increases (95% CI) in blood potassium from T_-10 and T₀ were 0.5 (0.4–0.6) and 0.4 (0.3–0.5) mEq/L, respectively. Blood potassium peaked at T₁, returned to baseline at T₃, and fell below the baseline at T₅. Peak blood potassium after reperfusion showed strong correlations with blood potassium measured at T_-10 (p < 0.001) and T₀ (p < 0.0001). These findings can support the establishment of future research plans and perioperative management of blood potassium in LDLT.

Post-Reperfusion Syndrome in Liver Transplantation: Does a Caval Blood Flush Vent Help?

BACKGROUND Post-reperfusion syndrome (PRS) during liver transplantation can range from a benign event to a profound hemodynamic excursion from baseline with significant morbidity. Multiple variables can be responsible for the diverse presentations. Over time, our group noticed that a blood flush of the liver graft via a caval vent (in addition to a standard chilled flush via the portal vein) appeared to result in a milder reperfusion effect. Attenuation of PRS via caval vent seemed to minimize hemodynamic instability and reduce metabolic derangements associated with reperfusion. MATERIAL AND METHODS This was a prospective observational pilot study of standard practice with the addition of lab values and hemodynamic evaluations. We methodically observed normal clinical flow in 20 adult orthotopic liver transplant recipients. We analyzed blood and fluid samples at set time intervals during the peri-reperfusion phase. RESULTS Sixteen out of 20 patients received a blood flush via caval venting. Mean arterial pressure (MAP) and heart rate were better preserved in the patient population that received a caval blood flush vent. Elevations in central venous pressure (CVP) were similar between the 2 groups. Lab values (blood gas, electrolyte, and hemoglobin) of the patients' blood were similar, with no notable differences. Analysis of the initial blood flushed through the liver graft proved to be hypothermic, acidotic, and hyperkalemic. CONCLUSIONS Pre-reperfusion caval venting in liver transplantation (in addition to a portal vent and a chilled LR/albumin portal flush solution) appears to have favorable hemodynamic effects. The literature on this technique is sparse and larger studies are needed.

Compared efficacy of University of Wisconsin and histidine-tryptophan-ketoglutarate solutions in ex-situ liver resection and autotransplantation for end-stage hepatic alveolar echinococcosis patients

BACKGROUND

The University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) solutions are the two most frequently used liver graft preservation fluids. The present study aimed to compare their efficacy in end-stage hepatic alveolar echinococcosis patients who underwent ex-situ liver resection and autotransplantation (ELRA).

METHODS

A total of 81 patients received ELRA from August 2010 to March 2018. They were allocated into UW (n = 48) and HTK groups (n = 33) based on the type of solutions used. Demographic and operational data were retrospectively analyzed. Primary outcomes included 90-day mortality, incidence of early graft loss, primary dysfunction, and postoperative complications.

RESULTS

Demographic and operational characteristics were similarly distributed in the two groups. No statistically significant differences were observed with regard to 90-day mortality (12.77% vs. 12.12%) and early graft loss rate (8.51% vs. 9.09%) between the two groups. Patients in the UW and HTK groups showed a primary dysfunction rate of 27.66% and 27.27%, respectively. The UW group exhibited a higher incidence tendency of biliary complications, albeit with no statistical significance.

CONCLUSIONS

This is the largest cohort study comparing the efficacy of the UW and HTK organ-preserving solutions in end-stage hepatic alveolar echinococcosis patients in ELRA settings. UW and HTK solutions presented similar efficacy and safety. A randomized clinical trial with larger scale is needed for further investigation in future clinical applications.

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.

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.

Postreperfusion hyperkalemia in liver transplantation using donation after cardiac death grafts with pathological changes

BACKGROUND

With the increasing use of donation after cardiac death (DCD), especially of the graft liver with steatosis or other pathological changes, the frequency of postreperfusion hyperkalemia in liver transplantation has increased significantly. The present study aimed to determine the factors associated with developing postreperfusion hyperkalemia in liver transplantation from DCD.

METHODS

One hundred thirty-one consecutive adult patients who underwent orthotopic liver transplantation from DCD were retrospectively studied. Based on serum potassium within 5 minutes after reperfusion, recipients were divided into two groups: hyperkalemia and normokalemia. According to preoperative biopsy results, the DCD graft livers were classified into five categories. Univariate analysis was performed using Chi-square test to identify variables that were significantly different between two groups. Multivariate logistic regression was used to confirm the risk factors of developing hyperkalemia and postreperfusion syndrome. Correlation analysis was used to identify the relationship between the serum concentration of potassium within 5 minutes after reperfusion and the difference in mean arterial pressure values before and within 5 minutes after reperfusion.

RESULTS

Twenty-two of 131 liver recipients had hyperkalemia episodes within 5 minutes after reperfusion. The rate of hyperkalemia was significantly higher in recipients of macrosteatotic DCD graft liver (78.6%, P<0.001) than that in recipients of non-macrosteatotic DCD graft liver. The odds ratio of developing postreperfusion hyperkalemia in recipients of macrosteatotic DCD graft liver was 51.3 (P<0.001). Macrosteatosis in the DCD graft liver was an independent risk factor of developing hyperkalemia within 5 minutes after reperfusion. The highest rate of postreperfusion syndrome also occurred in the recipients with macrosteatotic DCD graft liver (71.4%, P<0.001). A strong relationship existed between the serum potassium within 5 minutes after reperfusion and the difference in mean arterial pressure values before and within 5 minutes after reperfusion in macrosteatotic DCD graft liver recipients.

CONCLUSION

Macrosteatosis in the DCD graft liver was an independent risk factor of developing hyperkalemia and postreperfusion syndrome in the recipients.

Transdiaphragmatic resuscitative open cardiac massage: description of the technique and a first case-series of an alternative approach to the heart

BACKGROUND

The purpose of this paper is to describe the transdiaphragmatic approach to the heart for open CPR in patients that arrest at laparotomy and to present a first case series of patients that have undergone this procedure.

METHODS

All patients who had undergone intraperitoneal transdiaphragmatic open CPR between January 1, 2002 and December 31, 2012 were retrieved from the operation registry at Bern University Hospital, Switzerland. Transdiaphragmatic access to the heart is initiated with a 10-cm-long anterocaudal incision in the central tendon of the diaphragm--approximately at 2 o'clock. Internal cardiac compression through the diaphragmatic incision can be performed from both sides of the patient. From the right side of the patient, cardiac massage is performed with the right hand and vice versa.

RESULTS

A total of six patients were identified that suffered cardiac arrest during laparotomy with open CPR performed through the transdiaphragmatic approach. Four patients suffered cardiac arrest during orthotopic liver transplantation and two trauma patients suffered cardiac arrest during damage control laparotomy. In three patients, cardiac activity was never reestablished. However, three patients regained a perfusion heart rhythm and two of these survived to the ICU. One patient ultimately survived to discharge.

CONCLUSIONS

In patients suffering cardiac arrest during laparotomy, the transdiaphragmatic approach allows for a rapid, technically easy, and almost atraumatic access to the heart, with excellent CPR performance. After this potentially life-saving procedure, pulmonary or surgical site complications are expected to occur much less compared with the conventionally performed emergency department left-sided thoracotomy.

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

During liver transplant (LT), the release of vasoactive substances into the systemic circulation is associated with severe hemodynamic instability that is injurious to the recipient and/or the post-ischemic graft. Crystalloid flush with backward unclamping (CB) and portal blood flush with forward unclamping (PF) are two reperfusion methods to reduce reperfusion-related cardiovascular perturbations in our center. The primary aim of this study was to compare these two methods. After institutional review board (IRB) approval, cadaveric whole LT cases performed between 2003 and 2008 were reviewed. Patients were divided into two groups based on reperfusion methods: CB or PF. After background matching with propensity score, the effect of each method on post-operative graft function was assessed in detail. In our cohort of 478 patients, CB was used in 313 grafts and PF in 165. Thirty-day graft survival was lower, and risk of retransplantation was higher in PF. Multivariable model showed that CB is an independent factor to reduce primary non-function, cardiac arrest and improve 30-d graft survival. Also, the incidence of ischemic-type biliary lesions was significantly higher in the PF group. Reperfusion methods affect intraoperative hemodynamics and post-transplant outcome. CB allows for control over temperature and composition of the perfusate, perfusion pressure, and the rate of infusion.

Post-reperfusion syndrome during renal transplantation: a retrospective study

Post-reperfusion syndrome (PRS) is a serious, widely reported complication following the reperfusion of an ischemic tissue or organ. We sought to determine the prevalence, risk factors and short-term outcomes of PRS related renal transplantation. We conducted a retrospective, case-control study of patients undergoing renal transplantation between July 2006 and March 2008. Identification of PRS was based on a drop in mean arterial pressure by at least 15% within 5 minutes of donor kidney reperfusion. Of the 150 consecutive renal transplantations reviewed, 6 patients (4%) met criteria for post-reperfusion syndrome. Univariate analysis showed that an age over 60, diabetes mellitus, Asian race, and extended criteria donors increased the odds of developing PRS by 4.8 times (95% CI [1.2, 20]; P=.0338), 4.5 times (95% CI [1.11, 18.8]; P=.0378), 35.5 times (95% CI [3.94, 319.8]; P=0.0078) and 9.6 times (95% CI [1.19, 76.28] P=0.0115) respectively. Short term follow-up revealed increased graft failure rate within 6 months (6% vs. 16% P=0.0125) and almost twice the number of hospital days post-transplant in PRS cohorts (5.43 ± 2.29 vs. 10.8 ± 7.29 P=<0.0001). Despite limited reporting, PRS appears to be a relatively common complication of renal transplantation and is associated with increase morbidity.

Sodium, potassium and glucose management in organ transplantation

PURPOSE OF REVIEW

To present current knowledge about the metabolic management of patients undergoing solid organ transplantation, and potential organ donors.

RECENT FINDINGS

Appropriate management of electrolytes and glucose improves outcome after transplantation, although conflicting evidence exists. Patients with cirrhosis-induced hyponatremia can be successfully transplanted but are at increased risk of postoperative complications. A new class of drugs, the vaptans, that antagonizes arginine vasopressin may be an effective treatment for hyponatremia in transplant candidates. Recent literature has documented the implications, predictors and potential therapies for perioperative hyperkalemia in the transplant population. The debate over appropriate targets for serum glucose in perioperative and critically ill patients has been lively. The documented risk of hypoglycemia associated with 'intensive insulin therapy' has led to the adoption of more conservative glycemic targets. Studies of glycemic control in transplant recipients are limited.

SUMMARY

In patients undergoing solid organ transplants, sodium management should aim to minimize an acute change in sodium concentration. Vaptans may be of future use in optimizing patients with cirrhosis prior to transplantation. Pending further studies, a perioperative 'middle ground' target glucose of between 140 and 180 mg/dl seems reasonable at this time.