With the increasing maturity of liver transplantation techniques and experience with anesthesia, postoperative management of pediatric liver transplant recipients is becoming simpler, and the duration of postoperative intensive care is decreasing and early discharge rates are increasing. As with all major surgical procedures, appropriate preoperative management can lay the foundation for early postoperative recovery. Preoperative management of all complications of hepatic insufficiency, including reduction of portal hypertension, improvement of nutritional status, control of secondary infections, and correction of metabolic disorders, can significantly reduce postoperative surgery-related morbidity and mortality. Living liver transplantation is being widely performed, and this technique allows the surgeon to choose the right time to perform the surgery, gaining time to better improve the patient’s condition preoperatively. Difficulty in treating patients preoperatively often predicts specific intraoperative needs and good or bad postoperative outcomes. As can be seen, the treatment and care of children undergoing liver transplantation requires a collaborative effort between medical and surgical surgeons. This complementary medical-surgical working model can provide different expertise and techniques that make possible the best recovery for the child. I. Preoperative factors affecting the management of post-transplant patients 1. chronic biliary depressive liver disease The situation of all liver transplant recipients is not the same. The etiology of liver insufficiency in most pediatric liver transplant recipients is chronic biliary depressive disease. Children with biliary liver transplantation sclerosis usually have special nutritional requirements; these children are almost completely unable to absorb fat and caloric intake is often inadequate. In addition, children with cirrhosis may undergo liver transplantation with severe synthetic dysfunction and hypersplenism, and the corresponding coagulation defects as well as thrombocytopenia can increase the risk of intraoperative bleeding. When portal hypertension progresses to advanced hepatic failure with clinical development of uncontrollable ascites, relative hypoxemia, renal insufficiency, electrolyte disturbances, or new gastrointestinal bleeding. The risk and difficulty of liver transplantation increases at this time. In addition, these children have potentially suppressed autoimmune function, which increases the chance of postoperative infection. In addition to these common problems in chronic biliary cirrhosis, they also have specific hidden dysfunctions, which require that postoperative management should be tailored to the individual with special problems. For example, children with biliary atresia usually have a history of abdominal surgery, which increases intraoperative bleeding and unpredictable intestinal injury. In addition, children with biliary atresia may have a combination of other abnormalities, such as congenital heart disease or gastrointestinal malrotation. Some symptomatic biliary depression is associated with pulmonary hypertension. Children with advanced familial intrahepatic cholestasis often have defective small bowel function and may develop severe diarrhea after surgery, thus making it more difficult to treat with nutritional support and oral medications. Similarly, patients with primary sclerosing cholangitis may have occult intestinal disease, infectious disease, and pain medication dependence. All of these conditions require special management after transplantation. Then there are patients with chronic biliary depression who are chronically dependent on parenteral nutrition, which may be accompanied by underlying pulmonary disorders and critical gastrointestinal absorption dysfunction. Thus, only a full understanding of the patient’s preoperative systemic condition and disease can enable the postoperative management to achieve ideal results. 2. Fulminant liver failure Another pediatric disease that requires liver transplantation is acute liver failure. The course of liver failure varies from person to person and is usually accompanied by damage to other vital organs. This heterogeneous group of patients, in which the specific manifestations of multi-organ dysfunction are different for each individual, makes the requirements for postoperative management quite specific. Patients with acute liver failure are prone to severe hepatic encephalopathy and life-threatening cerebral edema. Rational management of fluid intake and output and correction of abnormalities in electrolytes, blood pressure and cerebral perfusion pressure will enable the patient to survive with or without surgery. It is necessary to place a device to measure cranial pressure in such patients, because the prognosis can be improved by timely management of cranial pressure changes, but this operation increases infection and bleeding. Unfortunately, high cranial pressure often does not return to normal soon after a successful liver transplantation and usually persists until the second to third day. Most patients have severe coagulation abnormalities and are at high risk for surgical hemorrhage. Further, the chance of sepsis is also higher in these patients, so they should be alert for signs of infection after surgery and apply antibiotics empirically to improve their prognosis. 3. Metabolic liver diseases The third group of pediatric diseases that require liver transplantation to resolve are metabolic liver diseases, including urea cycle defects, glycogen accumulation disorders, neonatal hemochromatosis, tyrosinemia, Crigler-Najjar
type I, α1-antitrypsin deficiency, and Wilson`s disease. This group has a history of special medication use and dietary restrictions prior to liver transplantation, and postoperative adjustments should be made accordingly. Some of these diseases require emergency liver transplantation in infancy, and technical complications can increase if the disease progresses, and lack of knowledge of the physiology of this disease can make postoperative treatment more difficult. Children with metabolic diseases usually also have associated damage to other organs, such as the brain and lungs, which can affect the patient’s tolerance to medications and other therapeutic outcomes after surgery. These diseases are not usually combined with portal hypertension, but some cases have been found to develop postoperative hepatocellular carcinoma. Repeat liver transplantation The last thing we would like to introduce is repeat liver transplantation in children. Re-transplantation is much more difficult than the first liver transplantation and therefore requires careful consideration and differentiated treatment after re-transplantation. Patients requiring a second liver transplant are at greater risk for perioperative complications, bleeding, unpredictable intestinal injury, poor wound healing, and severe acute cellular rejection. These patients have more or less compromised renal function due to long-term preoperative drug therapy, which also makes postoperative management more difficult. The postoperative outcome of these patients is influenced by several factors, such as the degree of hepatic insufficiency, nutritional status, and the presence or absence of biliary tract injury. The use of anti-rejection drugs is stronger than after the first transplantation. In addition, attention should be paid to post-operative CMV infection and lymphoproliferative disease. II. Surgical factors affecting liver transplant treatment It is necessary for the anesthesiologist to inform the ICU physician and the liver disease study group about the patient’s condition during liver transplantation. Although the surgeon can manage all aspects of the patient’s postoperative period in detail, it is important to have a multidisciplinary and complete postoperative management system in the end because the surgeon will inevitably have to perform other procedures and will need some relaxation after a procedure. The anesthesiologist should inform the ICU physician about intraoperative blood loss, transfusion volume, hourly urine volume, drugs used, intraoperative vital signs, laboratory results, cold ischemia time and heat ischemia time, vascular access, and monitoring modalities. What the surgeon should inform is the type of graft, characteristics of the donor liver, the color and texture of the graft at the time of recanalization, and details of the biliary and vascular anastomosis, the presence of intestinal injury, or spillage of intestinal contents, the size and location of the tracheal intubation, the type and number of drains, and the type of incision closure. When ICU physicians are provided with intraoperative details of the patient, it is beneficial for them to predict the considerations to be managed and the possible complications. The type of graft is again an important guide for post-count management. Due to the lack of small, suitable liver donors for children, graft surgeons have had to seek alternative solutions such as liver splitting or living liver transplantation, where a portion of the liver is taken and transplanted into the child. Many transplant centers have used partial liver lobes as a donor source for liver transplantation in children. The transplantation of a partial liver is inherently difficult, first of all, the anastomosis of the vessels and bile ducts is more difficult, and postoperative problems of abnormal blood flow or bile exposure are likely to occur. In addition, the presence of a hepatic section increases the risk of postoperative bile leakage and infection. The experience of the surgeon can greatly influence the outcome of the procedure. In general, only very experienced and technically mature transplant centers allow partial liver transplantation. Post-operative intensive care begins after the patient’s post-operative care has been provided to the ICU physician and hepatologist by the surgical staff. We promote routine postoperative treatment principles and consultation procedures. The first step in the management of a patient transferred to the monitoring unit is to connect the monitoring leads and fluid access and to connect mechanical ventilation. The patient’s status is then rapidly assessed to determine the adequacy of ventilation, hemodynamic stability, vascular access and monitoring patterns. The patient’s fluid balance should be assessed in terms of vital signs, central transcatheter pressure monitoring, capillary refill, and the difference between preoperative and postoperative weight. The need to regulate electrolyte and fluid balance, the need for supplemental blood products, satisfactory oxygenation and ventilation, the presence of acid-base imbalance, and an understanding of liver function are then determined based on hematologic and metabolic laboratory results. The location of the lines, drains and tracheal intubation should also be determined by chest and abdominal plain films. An abdominal ultrasound Doppler examination is performed within 12 hours postoperatively to understand the patency of the vessels and the amount of fluid in the abdomen. Of course, some transplant centers advocate that ultrasound should be performed more frequently. The transplant team usually follows a standardized weight-perimeter-based drug dosing regimen to minimize medication errors or missed medications. The classic postoperative regimen is as follows. 1.
Intravenous rehydration to maintain adequate intravascular volume and to ensure adequate perfusion of the graft and other organs. Buffered solutions such as lactated Ringers solution can be administered intravenously at 1.5 to 2 times the calculated rate obtained by IV drip. The rate of rehydration is adjusted at any time according to changes in cvp (maintained at 4 to 10) and hourly urine volume. Adjust acid-base imbalance and serum electrolyte abnormalities according to early laboratory findings techniques. Special attention should be paid to hyperkalemia and metabolic acidosis, which are 2 clues to early graft vascular volume response to intravascular volume or metabolic dysfunction. In patients at risk of cerebral edema, rehydration should be done with caution, being mindful of intravascular volume as well as the paradox of elevated cranial pressure. When the vena cava is cross-clamped, diuretics such as tachyphylaxis and renal doses of dopamine can be used to activate renal function. Patients with cirrhosis are highly absorbent of sodium and therefore retain more water in the body after transplantation, and the addition of diuretics is possible in this case.