Anesthesia for liver transplantation

Effects of Extracellular Calcium Concentration on Hepatic Ischemia-Reperfusion Injury in a Rat Model

OBJECTIVES

Hypocalcemia is frequently identified during liver transplant. However, supplementation of extracellular calcium could induce increased intracellular calcium concentration, as a potential factor for injury to the liver graft. We evaluated the effects of regulating extracellular calcium concentrations on hepatic ischemia-reperfusion injury.

MATERIALS AND METHODS

We randomly divided 24 Sprague-Dawley rats into 3 groups: group C received normal saline (n = 8), group L received citrate to induce hypocalcemia (n = 8), and group L-Co received citrate followed by calcium gluconate to ameliorate hypocalcemia (n = 8). Liver enzyme levels and extracellular calcium were measured before surgery, 1 hour after ischemia, and 2 hours after reperfusion. The primary outcome was liver enzyme levels measured 2 hours after reperfusion. In addition, we evaluated intracellular calcium levels, lactate dehydrogenase activity, and histopathological results in liver tissue.

RESULTS

Three groups demonstrated significant differences in extracellular calcium concentrations, but intracellular calcium concentrations in liver tissue were not significantly different. Group L showed significantly lower mean arterial pressure than other groups at 1 hour after ischemia (93.6 ± 20.8 vs 69.4 ± 14.2 vs 86.6 ± 10.4 mmHg; P = .02, for group C vs L vs L-Co, respectively). At 2 hours after reperfusion, group L showed significantly higher liver enzymes than other groups (aspartate aminotransferase 443.0 ± 353.2 vs 952.3 ± 94.8 vs 502.4 ± 327.3 U/L, P = .01; and alanine aminotransferase 407.9 ± 406.5 vs 860.6 ± 210.9 vs 333.9 ± 304.2 U/L, P = .02; for group C vs L vs L-Co, respectively). However, no significant difference was shown in lactate dehydrogenase and histological liver injury grade.

CONCLUSIONS

Administering calcium to rats with hypocalcemia did not increase intracellular calcium accumulation but instead resulted in less hepatic injury compared with rats with low extracellular calcium concentrations in this rat model study.

A Case Report of Cerebral Hypoperfusion During Liver Transplant with a Focus on the Role of Intraoperative Neuromonitoring

Acute hepatic failure is characterized by rapid deterioration of hepatic function with encephalopathy in a patient without pre-existing liver disease. Bispectral index values had a significant correlation with cerebral perfusion. Transcranial Doppler can assess changes in cerebrovascular function and has the advantages of being noteworthy and widely available. This is a case report of a hepatic encephalopathy occurring during a deceased donor liver transplant in a patient presenting fulminant hepatitis. We briefly discuss some diagnostic methods highlighting the challenges of the anesthesiologist in managing this kind of patient in the context of a major surgery.

Incidence of Postreperfusion Hyperfibrinolysis in Liver Transplantation by Donor Type and Observed Treatment Strategies

BACKGROUND

Hyperfibrinolysis is a possible complication during liver transplantation, particularly immediately after reperfusion.

METHODS

We performed a retrospective study to examine the incidence, treatment, and resolution of postreperfusion hyperfibrinolysis in patients undergoing liver transplantation at Duke University Hospital from 2015 to 2020.

RESULTS

Out of 535 patients undergoing liver transplantation, 21 or 3.9%, 95% CI (2.5-5.9), had hyperfibrinolysis after reperfusion. Hyperfibrinolysis occurred in 16 of 511 (3.1%) patients receiving livers from DBD donors, 5 of 18 (27.8%) patients receiving livers from donation after circulatory death (DCD) donors, and 0 of 6 (0.0%) patients receiving livers from living donors. Fibrinolysis was treated with cryoprecipitate (12/21), a combination of cryoprecipitate and tranexamic acid (3/21), or neither (6/21) and resolved within several hours in all cases.

CONCLUSIONS

Anesthesiologists should be aware of the possibility of postreperfusion hyperfibrinolysis in liver transplantation, particularly with DCD donors, and may consider treatment with cryoprecipitate or tranexamic acid. Further work is needed to identify any potential differences, such as faster resolution of fibrinolysis, between different treatment modalities.

The effect of thromboelastogram-guided transfusion on postoperative complications and transfusion requirement in the post-reperfusion period in liver transplantation surgery

Background/Aim: Liver transplantation surgery is one of the most common abdominal surgeries requiring blood transfusion. Coagulation parameters vary during the perioperative period because of the patient profile. Blood transfusion management should be carefully controlled to avoid causing dysfunction in the newly transplanted organ. Various laboratory parameters are used to achieve this. This study aimed to investigate the effect of transfusion managed by conventional coagulation tests or thromboelastogram (TEG) on blood product consumption and postoperative outcomes in the post-reperfusion period. Methods: The records of 90 recipients who underwent transplantation between January 1, 2012, and November 30, 2022, were retrospectively analyzed. Twenty patients who were administered blood transfusion under TEG guidance in the post-reperfusion period constituted the case group, while 20 patients non-consecutive randomly selected among other patients who were administered blood transfusion with conventional coagulation tests constituted the control group. In conclusion, 40 patients were included in this retrospective case-control study. We retrospectively analyzed demographic data, surgical data, perioperative laboratory parameters, intraoperative total and post-reperfusion blood and blood product transfusions, TEG parameters, and postoperative complications. Results: No difference was found between the groups regarding demographic data, etiological factors, surgical data, and preoperative laboratory parameters (P>0.05). There was a significant decrease in the amount of fresh frozen plasma (FFP) transfused in the case group compared to the control group in the intraoperative total and post-reperfusion period (P=0.011, P=0.003). There was no difference between the groups regarding other blood product transfusions and postoperative complications (P>0.05). Regarding the effects of intraoperative total and post-reperfusion blood and blood products on ventilator stay, intensive care unit stay, length of stay (LOS), hepatic artery thrombosis, graft rejection, postoperative kidney damage, and first 28-day mortality, only a weak negative correlation was found between intraoperative total and postreperfusion fibrinogen use and LOS (r=-0.325/P=0.041, r=-0.354/P=0.025). Conclusion: TEG-guided transfusion in the post-reperfusion period reduced total blood product consumption. Besides, the increase in the use of fibrin has led to a decrease in LOS. However, using TEG has no significant effect on postoperative mortality and morbidity. TEG and an objective assessment of patient clinical status may be an ideal guide for transfusion strategy.

Patterns of Use in Transesophageal Echocardiography for Liver Transplantation: A Systematic Review

Transesophageal echocardiography is frequently but not always used to guide anesthetic management during liver transplantation. We performed a systematic review of the literature to identify and summarize any studies reporting on the frequency and characteristics of TEE use for liver transplantation. Studies were identified by searching several relevant terms on PubMed and citation searching of relevant reviews. We identified 5 studies reporting the results of surveys performed between 2003 and 2018. Use of TEE for liver transplantation increased from 11.3% of centers in 2003 to greater than 90% of centers by 2014 and 2018. Only 38%-56% of centers use it routinely with the rest using it only in special circumstances. About a third of centers usually perform a comprehensive exam, with the majority performing a more limited exam based on the needs of the case. Use of TEE for liver transplantation is common but not universal. This review summarizes the current knowledge about the frequency and circumstances of use, but there is an opportunity for further systematic study and discussion.

Magnetic-assisted laparoscopic liver transplantation in swine

BACKGROUND

Although laparoscopic technology has achieved rapid development in the surgical field, it has not been applied to liver transplantation, primarily because of difficulties associated with laparoscopic vascular anastomosis. In this study, we introduced a new magnetic-assisted vascular anastomosis technique and explored its application in laparoscopic liver transplantation in pigs.

METHODS

Two sets of magnetic vascular anastomosis rings (MVARs) with different diameters were developed. One set was used for anastomosis of the suprahepatic vena cava (SHVC) and the other set was used for anastomosis of the infrahepatic vena cava (IHVC) and portal vein (PV). Six laparoscopic orthotopic liver transplantations were performed in pigs. Donor liver was obtained via open surgery. Hepatectomy was performed in the recipients through laparoscopic surgery. Anastomosis of the SHVC was performed using hand-assisted magnetic anastomosis, and the anastomosis of the IHVC and PV was performed by magnetic anastomosis with or without hand assistance.

RESULTS

Liver transplants were successfully performed in five of the six cases. Postoperative ultrasonographic examination showed that the portal inflow was smooth. However, PV bending and blood flow obstruction occurred in one case because the MVARs were attached to each other. The durations of loading of MVAR in the laparoscope group and manual assistance group for IHVC and PV were 13 ± 5 vs. 5 ± 1 min (P < 0.01) and 10 ± 2 vs. 4 ± 1 min (P < 0.05), respectively. The durations of MVAR anastomosis in the laparoscope group and manual assistance group for IHVC and PV were 5 ± 1 vs. 1 ± 1 min (P < 0.01), and 5 ± 1 vs. 1 ± 1 min (P < 0.01), respectively. The anhepatic phase was 43 ± 4 min in the laparoscope group and 23 ± 2 min in the manual assistance group (P < 0.01).

CONCLUSIONS

Our study showed that magnetic-assisted laparoscopic liver transplantation can be successfully carried out in pigs.

Calcium Chloride Requirement and Postreperfusion Rebound During Massive Transfusion in Liver Transplantation

OBJECTIVES

The administration of citrated blood products during massive transfusion requires calcium salt administration to prevent citrate toxicity and to maintain ionized calcium values. The literature does not provide adequate guidance for the amount of calcium required during massive transfusions during liver transplantation. This study was conducted to provide guidance on calcium salt replacement during a massive transfusion in liver transplant patients, with a focus on the phase of transplantation during which citrate metabolism was minimal.

DESIGN

An observational retrospective chart review.

SETTING

An academic single-institution study of hospitalized patients.

PARTICIPANTS

One hundred thirty-two patients after liver transplantation.

INTERVENTIONS

The study authors observed documented measurements of ionized calcium and observed the ratio of calcium salts to citrated bank blood products in patients undergoing liver transplantation with complete data sets. They also observed the effect of continuous venovenous hemofiltration on the distribution of ionized calcium values.

MEASUREMENTS AND MAIN RESULTS

Prereperfusion, an average of 1.09 g CaCl₂/L of citrated blood was administered to maintain ionized calcium in the normal range. Postreperfusion, less CaCl₂ was administered, and a rebound of ionized calcium occurred. Prereperfusion, continuous venovenous hemofiltration reduced the number of ionized calcium values outside of 2 standard deviations, meaning fewer values were critically low.

CONCLUSIONS

With massive transfusions up to 67 liters (approximately 13 blood volumes), 1.09 g CaCl₂/L citrated blood maintained ionized calcium in the normal range in the absence of citrate metabolism. This ratio may have value in empiric treatment when ionized calcium measurements are unavailable, and massive transfusion rates exceed metabolic capacity.

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.

Association between surgical volumes and hospital mortality in patients: a living donor liver transplantation single center experience

Background

Many factors cause hospital mortality (HM) after liver transplantation (LT).

Methods

We performed a retrospective research in a single center from October 2005 to June 2019. The study included 463 living donor LT patients. They were divided into a no-HM group (n = 433, 93.52%) and an HM group (n = 30, 6.48%). We used logistic regression analysis to determine how clinical features and surgical volume affected HM. We regrouped patients based on periods of surgical volume and analyzed the clinical features.

Results

Multivariate analysis revealed that donor age (OR = 1.050, 95% CI 1.011–1.091, p = 0.012), blood loss (OR = 1.000, 95% CI 1.000–1.000, p = 0.004), and annual surgical volumes being < 30 LTs (OR = 2.540, 95% CI 1.011–6.381, p = 0.047) were significant risk factors. A comparison of years based on surgical volume found that when the annual surgical volumes were at least 30 the recipient age (p = 0.023), donor age (p = 0.026), and ABO-incompatible operations (p < 0.001) were significantly higher and blood loss (p < 0.001), operative time (p < 0.001), intensive care unit days (p < 0.001), length of stay (p = 0.011), rate of re-operation (p < 0.001), and HM (p = 0.030) were significantly lower compared to when the annual surgical volumes were less than 30.

Conclusions

Donor age, blood loss and an annual surgical volume < 30 LTs were significant pre- and peri-operative risk factors. Hospital mortality and annual surgical volume were associated with statistically significant differences; surgical volume may impact quality of care and transplant outcomes.

Transfusion-Related Acute Lung Injury During Liver Transplantation: A Scoping Review

Liver transplantation is associated with significant blood loss, often requiring massive blood product transfusion. Transfusion-related acute lung injury (TRALI) is a devastating cause of transfusion-related deaths. While reports have investigated the general incidence of TRALI, the incidence of TRALI specifically following transfusion during liver transplant remains unclear. This scoping review summarizes existing literature regarding TRALI during the liver transplantation perioperative period. Databases were searched for all articles and abstracts reporting on TRALI after liver transplantation. Data collected included number of patients studied, patient characteristics, incidences of TRALI, TRALI characteristics, and patient outcomes. The primary outcome investigated was the incidence of TRALI in the setting of liver transplantation. Thirteen full-text citations were included in this review. The incidence of TRALI post-liver transplant was 0.68% (65 of 9,554). Based on reported transfusion data, patients diagnosed with TRALI received an average of 10.92 ± 10.81 units of packed red blood cells (pRBC), 20.05 ± 15.72 units of fresh frozen plasma, and 5.75 ± 10.00 units of platelets. Common interventions following TRALI diagnosis included mechanical ventilation with positive end-expiratory pressure, inhaled high-flow oxygen, inhaled pulmonary vasodilator, and pharmacologic treatment using pressors or inotropes, corticosteroids, or diuretics. Based on reported mortality data, 26.67% of patients (12 of 45) diagnosed with TRALI died during the postoperative period. This scoping review underscores the importance of better understanding the incidence and presentation of TRALI after liver transplant surgery. The clinical implications of these results warrant the development of identification and management strategies for liver transplant patients at increased risk for developing TRALI.

Five-lead Electrocardiography During Living Donor Liver Transplantation: Incidence and Clinical Significance of ST Segment Abnormality

OBJECTIVES

Five-lead electrocardiography (ECG) is commonly used during liver transplantation, while 3-lead ECG is used during most noncardiac operations. This study aimed to evaluate the incidence and clinical significance of ST segment abnormality during living donor liver transplantation (LDLT) with 5-lead ECG.

METHODS

We retrospectively reviewed medical records of patients who received LDLT between May 2018 and May 2019. A total of 109 adult recipients underwent LDLT, and 108 recipients were divided into 2 groups according to whether or not significant ST segment abnormality had occurred at 8 predetermined time points during the operation. ST segment change by more than 1 mm was regarded as significant.

RESULTS

Of the 108 recipients, 21 recipients (19.4%) had significant ST segment depression during the operation. No case of significant ST segment elevation was noted. The significant ST segment depression was detected mostly in lead II and V5, and with 2 in combination we could detect 95.2% of significant ST segment change. The significant ST segment depression was frequently observed 1 hour after anhepatic phase and 2 hours after reperfusion. Patient characteristics were not different between the 2 groups. Moreover, the cardiac enzyme (troponin I) measurements, measured immediately after the operation, were not different between the 2 groups.

CONCLUSIONS

Although significant ST segment change was frequently observed during LDLT, more studies are required to determine the clinical significance of 5-lead ECG ST segment abnormality during LDLT.

Intraoperative Hemodynamic Parameters and Acute Kidney Injury After Living Donor Liver Transplantation

BACKGROUND

Acute kidney injury (AKI) after living donor liver transplantation (LDLT) is associated with increased mortality. We sought to identify associations between intraoperative hemodynamic variables and postoperative AKI.

METHODS

We retrospectively reviewed 734 cases of LDLT. Intraoperative hemodynamic variables of systemic and pulmonary arterial pressure, central venous pressure (CVP), and pulmonary artery catheter-derived parameters including mixed venous oxygen saturation (SvO2), right ventricular end-diastolic volume (RVEDV), stroke volume, systemic vascular resistance, right ventricular ejection fraction, and stroke work index were collected. Propensity score matching analysis was performed between patients with (n = 265) and without (n = 265) postoperative AKI. Hemodynamic variables were compared between patients with AKI, defined by Kidney Disease Improving Global Outcomes criteria, and those without AKI in the matched sample.

RESULTS

The incidence of AKI was 36.1% (265/734). Baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were significantly different between patients with and without AKI in the matched sample of 265 pairs. Multivariable logistic regression analysis revealed that baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were independent predictors of AKI (CVP per 5 cm H2O increase: odds ratio [OR], 1.20; 95% confidence interval [CI], 1.09-1.32; SvO2: OR, 1.45; 95% CI, 1.27-1.71; RVEDV: OR, 1.48; 95% CI, 1.24-1.78).

CONCLUSIONS

The elevated baseline CVP, elevated baseline RVEDV after anesthesia induction, and decreased SvO2 during anhepatic phase were associated with postoperative AKI. Prospective trials are required to evaluate whether the optimization of these variables may decrease the risk of AKI after LDLT.

Potassium levels after liver reperfusion in adult patients undergoing cadaveric liver transplantation: A retrospective cohort study

Background

Hyperkalemia is a common cause of arrhythmias in patients undergoing liver transplantation. We examined the pattern of change of potassium levels during and immediately after reperfusion of the donor liver.

Materials and methods

Potassium levels of 30 consecutive adult patients undergoing cadaveric liver transplantation were assessed before and after liver reperfusion. Changes in potassium levels over 13 predefined timepoints were analyzed. Primary aim: to describe the pattern of change of potassium levels during the reperfusion period. Correlation between changes in potassium levels during reperfusion and a-priori variables were investigated.

Results

Baseline median (IQR) potassium levels were 4.1 (3.8:4.5) mmol/L. Thirteen patients (43%) developed hyperkalemia, 10 (33%) of whom developed severe hyperkalemia. Potassium levels peaked at 80 s post reperfusion, plateaued until 2 min, before returning toward baseline values at 5 min. There was a strong association between pre-reperfusion/baseline potassium levels and peak potassium values during reperfusion (95%CI: 0.26 to 0.77, p < 0.001). A baseline potassium level of 4.45 mmol/L was a good predictor of reperfusion hyperkalemia with a sensitivity of 69.2% and specificity of 94.1% (AUC = 0.894, 95%CI: 0.779 to 1.000, p < 0.001).

Conclusion

Hyperkalemia during cadaveric liver transplantation is common affecting almost 1 in 2 patients during reperfusion. During reperfusion potassium levels peaked within 2 min and over a third of patients developed severe hyperkalemia. Higher peak potassium levels correlated strongly with higher pre-reperfusion potassium values. These findings guide clinicians with timing of sampling of blood to check for hyperkalemia and identify modifiable factors associated with the development of hyperkalemia.

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Hyperkalemia during the reperfusion phase of cadaveric liver transplantation is common.

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Potassium levels peaked at 80 s post reperfusion, plateaued for 2 min, and returned to baseline at 5 min.

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There was a strong association between pre-reperfusion potassium levels and peak potassium values during reperfusion.

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Timing of blood sampling to check for hyperkalemia is paramount.

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A baseline potassium level of greater than 4.45 mmol/L was a good predictor of reperfusion hyperkalemia.

Anaesthesia for Liver Transplantation: An Update

Liver transplantation (LT) is a challenging surgery performed on patients with complex physiology profiles, complicated by multi-system dysfunction. It represents the treatment of choice for end-stage liver disease. The procedure is performed under general anaesthesia, and a successful procedure requires an excellent understanding of the patho-physiology of liver failure and its implications. Despite advances in knowledge and technical skills and innovations in immunosuppression, the anaesthetic management for LT can be complicated and represent a real challenge. Monitoring devices offer crucial information for the successful management of patients. Hemodynamic instability is typical during surgery, requiring sophisticated invasive monitoring. Arterial pulse contour analysis and thermo-dilution techniques (PiCCO), rotational thromboelastometry (RO-TEM), transcranial doppler (TCD), trans-oesophageal echocardiography (TEE) and bispectral index (BIS) have been proven to be reliable monitoring techniques playing a significant role in decision making. Anaesthetic management is specific according to the three critical phases of surgery: pre-anhepatic, anhepatic and neo-hepatic phase. Surgical techniques such as total or partial clamping of the inferior vena cava (IVC), use of venovenous bypass (VVBP) or portocaval shunts have a significant impact on cardiovascular stability. Post reperfusion syndrome (PRS) is a significant event and can lead to arrhythmias and even cardiac arrest.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Upper Extremity Compartment Syndrome Following Radial Artery Puncture in a Patient Undergoing Orthotopic Liver Transplant

Acute compartment syndrome is the physiologic consequence of increasing pressures within an enclosed anatomic space; if left untreated, it can subsequently cause irreversible necrosis, nerve injury, and tissue damage. A number of iatrogenic causes have been reported in the literature; however, to the best of our knowledge, there are no prior reports of upper extremity compartment syndrome in orthotopic liver transplant following arterial line placement. Here, we report a 52-year-old male with a history of end-stage liver disease secondary to primary sclerosing cho-langitis who presented for orthotopic liver transplant. A radial arterial line with 20-gauge catheter was placed atraumatically without complication. Intraoperatively, the patient developed severe coagulopathy. The cause was likely multifactorial, including dilution of factors from the massive blood loss during the dissection phase, a prolonged anhepatic period, and delayed graft function, resulting in decreased production of coagulation factors. This consumptive process likely subjected minor vascular injury to potential bleeding and caused a slow cumulative bleed into the right forearm, resulting in compartment syndrome. This case exemplifies the complications that can occur from arterial line placement in a liver transplant recipient who develops severe intraoperative coagulopathy. This can arguably be extrapolated to any situation caused by significant dilutional coagulopathy or a consumptive process, such as disseminated intra-vascular coagulation. As such, when large-volume blood transfusions are anticipated, we recommend that all central venous and arterial accesses be obtained under ultraso-nographic guidance and that frequent extremity physical examinations should be performed at a minimum of every hour. Correcting the underlying coagulopathy is imperative to resolve ongoing bleeding, a high index of suspicion is warranted, and immediate diagnosis and therapy are integral to improving patient outcomes.