Anesthesia Management of Miller Liver Transplantation (6) Anhepatic Stage of Operation

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The anesthesiologist's focus is on: temporary changes in health status, hospitalization (if infection is present, new-onset encephalopathy, variceal hemorrhage, ascites, or hemodynamic deterioration should be considered), assessment of initial and subsequent cardiorespiratory details (Assess for coronary artery disease, heart failure, pulmonary hypertension, or arrhythmias) and renal status (AKI), patients with oliguria, acidemia, and renal replacement therapy may benefit from intraoperative renal replacement therapy
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The surgery is divided into three distinct phases: Anhepatic pre-stage (hepatectomy phase) - the liver is removed and the vascular structures (suprahepatic, inferior inferior vena cava, portal vein, and hepatic artery) are marked
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The anhepatic phase - begins with the blocking of these vessels, removal of the original liver, and continues until the transplanted liver is implanted
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Reperfusion (usually through the portal vein) marks the beginning of the neohepatic phase and continues until completion of the remaining vascular anastomosis (usually the hepatic artery), bile duct anastomosis, hemostasis, and abdominal closure
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Intraoperative management · Emergency, ascites - rapid sequential induction · Establishment of large-bore venous access, invasive arterial, three-lumen 9F central vein, or considering major bleeding (re-liver transplantation or history of major abdominal surgery) Place two 9F central venous catheters
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Pulmonary artery catheters are commonly used in adult patients, but may be omitted if the recipient has not had recent pulmonary hypertension
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• Intraoperative TEE is increasingly being used
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Even in the presence of esophageal varices, the likelihood of bleeding complications from TEE remains low
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A pulmonary artery catheter must be placed if continuous intraoperative monitoring of pulmonary arterial pressure is required, or if postoperative ICU hemodynamics and fluid management are used
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·Rapid blood transfusion system with high flow rate (>500ml/min) is often used, which is beneficial to volume replacement and blood transfusion management
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·Balanced anesthesia is usually used, usually with low to moderate concentrations of 0.
5-1 MAC volatile anesthetics to keep the patient unconscious, and opioids are used
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Fentanyl is usually used to block the sympathetic response to stimulation and provide a smooth transition for postoperative analgesia.
Hypotension requires suspension of volatile anesthesia
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· Midazolam has little effect on hemodynamics and can still be used to perform its previous role in the event of hypotension
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· Advantages of isoflurane: It protects splanchnic blood flow, produces vasodilation effect in hepatic circulation, and is beneficial to hepatic oxygen supply, which is beneficial to perfusion of new liver
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• Compound A, the breakdown product of sevoflurane, has been found to be nephrotoxic in animals, but has not shown nephrotoxicity in humans even with low-flow anesthesia
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· Shunazil is organ-independent for its elimination and reduces histamine release, making it a good neuromuscular blocker in liver transplant patients
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·In patients with end-stage liver disease, the volume of distribution and hepatic clearance of cisa are increased, resulting in similar elimination half-life and duration of muscle relaxation (time to 25% recovery)
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Anhepatic pre-traditional orthotopic liver transplantation requires occlusion of the portal vein, suprahepatic IVC, infrahepatic IVC and hepatic artery
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·If the piggyback technique is used, the original retrohepatic inferior vena cava will be preserved
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· Anhepatic prephase includes dissection of the original liver and identification of the hepatic hilum
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Hypovolemia occurs with laparotomy and drainage of ascites
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• Treatment with colloid-containing fluids should be pre-treated to reduce preload variability
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If coagulopathy is already present, fresh frozen plasma should be infused immediately after skin incision, although some authors have questioned the use of fresh plasma in liver transplantation
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In Europe, PCCs prothrmbin cornplex concentrates containing VK-dependent coagulation factors (2.
7.
9.
10) are increasingly replacing plasma transfusions to avoid transfusion-related acute lung injury and transfusion-induced circulatory overload load
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• Some authors believe that coagulation monitoring does not affect the need for blood products in orthotopic liver transplantation
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However, in cardiac surgery patients with coagulopathy, the use of TEG monitoring for guidance reduces red blood cell and plasma transfusions and improves 6-month survival
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Fibrinolysis is uncommon in the anhepatic pre-anemia, therefore, cryoprecipitation is usually not necessary
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Hyponatremia should not be corrected quickly, and perioperative serum sodium increases of 21-32 mEq/L can cause central pontine myelinolysis, whereas increases of less than 16 mEq/L do not
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Citric acidosis (hypocalcemia caused by the infusion of citric acid-rich blood products in the absence of liver function) can be treated with calcium chloride
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· Citric acid infusion can cause hypomagnesemia, but magnesium values ​​gradually return to normal after graft reperfusion
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Aggressive treatment of hypokalemia is best avoided, especially when serum potassium rises in preparation for reperfusion
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Hyperkalemia should be treated with diuretics and insulin plus glucose, and if ineffective, intraoperative dialysis should be used
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· Hyperglycemia should be avoided, over 180mg/dl increased infection rate
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Blood gases, electrolytes, blood glucose, free calcium, and hemoglobin should be monitored regularly and hourly in the presence of massive blood loss or abnormalities
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Coagulation tests are usually performed at the beginning of surgery, after correction of specific coagulation disorders, after reperfusion, and in the presence of microvascular bleeding
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Advisable to maintain urine output, but use of low-dose dopamine for this purpose has not been demonstrated
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· Hypothermia should be avoided
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Anhepatic phase The anhepatic phase begins with occlusion of hepatic blood flow and ends with graft reperfusion
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    Blockade of suprahepatic and subhepatic IVCs can reduce venous return by up to 50%
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    Veno-venus bypass (VVB) diverts blood flow from the inferior vena cava and portal vein to the superior vena cava through the axillary vein, thereby alleviating the reduction of preload, increasing renal perfusion pressure, and reducing splanchnic congestion.
And can delay the occurrence of metabolic acidosis
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    Using a piggyback preserves the IVC, reducing the need for VVB
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    After hepatectomy, hemostasis and anastomosis of the suprahepatic and infrahepatic IVC and portal veins are required
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    Although there are no liver-produced coagulation factors during the anhepatic phase, blood loss is usually modest because the blood vessels that enter the liver have been clamped
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    However, at this stage, fibrinolysis may begin to occur due to lack of liver-produced plasminogen activator inhibitor, resulting in no action against tissue plasminogen activator
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Recommended reading for the new liver stage Anesthesia Management Specification for Chinese Children's Liver Transplantation Prof.
Yu Weifeng Part of the courseware of the Pediatric Liver Transplant Annual Meeting A case of anesthesia management in a patient with portal-pulmonary hypertension undergoing liver transplantation - TEE, another example of liver transplantation anesthesia Perspective (Ji Xiaolin) The summary post you want is here! ! ～～2021 Update Anesthesia Management of Miller Liver Transplantation (1) Indications & Trends Anesthesia Management of Miller Liver Transplantation (2) Pathophysiology of End-Stage Liver Disease [Monday] Anesthesia Management of Miller Liver Transplantation (3) End Pathophysiology of end-stage liver disease [Monday] Miller · Anesthesia management of liver transplantation (4) Surgical process 【Monday】 Miller · Anesthesia management of liver transplantation (5) The operation process of anesthesia in the early stage of liver transplantation is all in the micro shop~