Liver surgery has made rapid progress in recent years, and the mortality rate of cardiac and hepatic resection in major liver surgery is less than 3%, but liver failure remains the major cause of death after various treatments, especially surgical treatments. Therefore, the reserve function of the patient’s liver must be accurately assessed prior to treatment. The current methods of preoperative liver reserve function testing and assessment include the following four aspects: (1) routine liver function tests, such as changes in bilirubin, bile acids and prothrombin; (2) some semi-quantitative tests of liver function, such as indocyanine green (ICG), lidocaine metabolism test ( monoethylglycinexylidide (MEGX), oral glucose tolerance test and glucagon load test, aminopyrine profile test, 13C a methadrexate breath test, etc.; (3) imaging test methods, including liver volume measurement, functional liver volume measurement evaluation, etc.; (4) other tests of liver function, including portal pressure measurement, liver Fibrosis index, etc. I. Routine liver function tests Routine liver function tests can make a preliminary evaluation of liver function, the main index bilirubin, liver enzyme tests, such as serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), and other alkaline phosphatase (ALT). Other enzymes such as alkaline phosphatase (ALP), r-glutamyltransferase (γ-GT), leucine aminotransferase, 5′-nucleotidase, serum albumin and transferrin, lipids and lipoproteins can reflect the functional status of the liver from different aspects. 1.Bilirubin is the end product of erythrocyte destruction. Serum bilirubin concentration reflects the balance between the production and excretion of such metabolic end products in human body. Indirect bilirubin may indicate hemolysis or hepatocyte damage or necrosis. Direct bilirubin indicates impaired hepatic bile excretion or biliary obstruction. A few hereditary diseases may also show specific metabolic abnormalities of these two types of bilirubin, such as Gilbert’s disease, which may manifest as congenital unconjugated hyperbilirubinemia. 2. Hepatic transaminases The release of enzymes from damaged hepatocytes during liver disease can lead to elevated serum transaminases. The degree of transaminase elevation usually reflects the severity of hepatic necrosis, except for alcoholic hepatitis, which usually rarely exceeds 200-300 IU/L. 3.Alkaline phosphatase activity A variety of tissues and cells in the body have ALP activity, including liver, bile duct, small intestine, bone, kidney, placenta and leukocytes, etc. Therefore, lesions in these tissues can show changes in ALP levels, and non-hepatobiliary system diseases such as pregnancy, Non-hepatobiliary disorders such as pregnancy, normal growth phase and bone tumors, as well as hepatobiliary disorders such as hepatocellular damage and biliary obstruction can show elevated ALP levels. Specifically, elevated ALP activity has three implications: first, increased synthesis of the enzyme itself; second, impaired excretion of the enzyme from the biliary tract and obstructed excretion; and third, increased release of the enzyme in response to cellular injury. All three of these conditions can occur in hepatic surgery, but ALP elevation is most pronounced in extrahepatic biliary obstruction, followed by intrahepatic bile depression and liver tumors, which can also show abnormal expression of ALP enzyme. The degree of ALP elevation has been found to be somewhat predictive of the severity of liver disease or metastatic lesions. In most cases, there is an obvious cause for ALP elevation; however, if the cause of the elevation is unknown, electrophoresis and other methods can be used to examine the relevant enzymes in liver function, especially changes in their isoenzymes, for differential diagnosis. The most common clinical method is to simultaneously test the activity of 5-nucleotidase, leucine aminopeptidase, and GGT. The presence of liver disease is often indicated when these enzymes are elevated simultaneously with ALP. 4. Albumin Serum albumin is an important indicator to evaluate the synthetic function of the liver. Although the metabolic mechanism of albumin is still not well understood, in human body, albumin is only synthesized in the liver, so its level can reflect the protein synthesis function of the liver to a certain extent. It has been found that a variety of factors can affect the level of albumin, so when using albumin to analyze liver function clinically, it is necessary to exclude the role of factors other than the liver, such as the patient’s nutritional status, the level of thyroid hormones or adrenal corticosteroids, and the excessive excretion of albumin due to certain diseases, such as burns, sepsis, nephrotic syndrome, protein-losing enteropathy and other cases of albumin The condition of large amount of loss. After excluding other special factors mentioned above, serum albumin concentration is a more objective indicator to evaluate the changes of liver synthesis. Since the normal synthesis rate of albumin is 110-200mg/kg/day and the half-life is long, the albumin concentration can only reflect the chronic change process of liver function. 5.Serum pre-albumin (PA) Like albumin, PA is a kind of glycoprotein synthesized by the liver, which belongs to the rapid transformation protein of serum, and the synthesis rate in the liver is 99%. Because of its short half-life (about 1.9 days), it can reflect liver inflammation and patient’s liver function damage in a more sensitive way than albumin (Alb), and combined with other indicators such as total bilirubin, it can be used to assess liver function and guide treatment. 6.Transferrin is synthesized in the liver, and its half-life is shorter than that of albumin, so the measurement of serum transferrin can reflect the subacute changes in liver function. In addition, there are changes in lipids and lipoprotein electrophoresis in acute or chronic liver disease, mainly due to abnormal synthesis. Although there are many studies on the determination of this type of protein, it has not been widely used in clinical practice so far. 7.Gamma-globulin is synthesized by the monocyte-phagocytic system, and the main components include immunoglobulins (IgG, IgA and IgM), and C-reactive protein. Hepatic impairment often leads to a decrease in serum albumin and an increase in extrahepatic synthesis of globulins, especially γ-globulins. In the presence of immune diseases, γ-globulins can be significantly elevated, but in patients with cirrhosis, excluding autoimmune diseases, elevated γ-globulins can be considered an important predictor of the degree of cirrhosis or hepatic impairment [2]. It is believed that preoperative γ-globulin >26% has a significantly higher likelihood of postoperative liver failure. 8.Coagulation test Prothrombin time can be used for the determination of liver failure. Prolonged prothrombin time indicates not only the lack of prothrombin complex, but also the lack of coagulation factors IX and XII. For individual coagulation factor test, if the concentration of coagulation factor V is less than 10%, it indicates serious liver function damage and poor prognosis. In addition, the ratio of coagulation factor VIII to V also has a certain reference significance II. Semi-quantitative tests of liver function In addition to the conventional functional tests of the liver, some semi-quantitative functional tests of the liver can also reflect the function of the liver in different degrees. Among them, ICG and MEGX are more frequently studied in clinical practice, and they are combined with total bilirubin or liver residual volume measurement in Japan, Hong Kong, Europe and America for clinical assessment of liver function and treatment selection. 1. Indocyanine green test (ICG) ICG can be selectively taken up by hepatocytes after intravenous injection, and then gradually excreted into the bile, ICG is not excreted from the kidney and does not participate in the enterohepatic circulation, so the absorption and excretion of ICG can reflect the reserve function of the liver. The ICG excretion test can objectively reflect the absorption and excretion function of the liver, and is useful for the selection of surgical procedures and the determination of the timing of surgery. The ICG excretion test can objectively reflect the absorption and excretion function of the liver, and is useful for the selection of surgical procedure and the timing of surgery. Some people combined ICG with total bilirubin for the selection of liver surgical treatment, and concluded that under the condition of normal bilirubin, right hemicolectomy, enlarged right hemicolectomy or left trilobar resection is feasible for ICGR15<10%, left hemicolectomy can be tolerated for ICGR15 in 10%-19%, segmental resection is feasible for ICGR15 in 20%-29%, local tumor resection can be considered for ICGR15 in 30%-39%. In ICGR15>40%, only “tumor excision” can be performed. As for the choice of surgical treatment for hepatocellular carcinoma combined with portal hypertension, when ICGR15<20%, combined hepatic resection + portacaval dissection can be performed if the liver volume is well compensated; while when ICGR15>20%, adequate preparation should be made before performing combined surgery to enhance the tolerance of the liver to the surgery; while when ICGR15>25%, especially if the liver is significantly shrunken due to cirrhosis, combined surgery should not be performed. In addition, there are some limitations of ICG assay, one of which is the inconsistency of the current standard range of ICG assay, and the other is that ICGR15 fluctuates widely in patients with postoperative liver failure, while ICG itself is only a reflection of the absorption and excretion function of the liver, and multifactorial analysis shows that ICG is not a relevant factor for postoperative liver failure in patients. Therefore, the exact role of ICG in the assessment of liver function needs to be studied in depth. 2. Lidocaine metabolism test Lidocaine is oxidatively demethylated by the cytochrome P-450 system to produce monoethylglycinexylidide (MEGX), which is eventually cleared. MEGX clearance can be measured 15 minutes after intravenous lidocaine injection to quantitatively assess the function of the liver. This method is often used clinically for monitoring liver function in liver transplant donors and recipients. Lidocaine clearance is influenced by three factors, including the number of viable hepatocytes, the activity of hepatic cytochrome P450 enzymes, and hepatic blood flow.Ercolani et al. performed the MEGX test in 200 patients with different liver diseases and 23 organ donors and showed that patients were susceptible to hepatic insufficiency after hepatectomy when MEGX was <25 ng/ml, and when Ravaioli et al. also concluded that preoperative MEGX values below 25 ng/ml were associated with postoperative liver insufficiency and postoperative complications after hepatectomy. In addition, it has also been found that there is a correlation between residual liver volume and MEGX, and that changes in preoperative and postoperative MEGX can be used to reflect changes in residual liver volume and thus to assess postoperative liver function. 3. aminopyrine breath test (ABT) In vivo metabolism of aminopyrine is catalyzed by hepatic cytochrome P450 enzymes to remove the two methyl groups at the N position to produce aminoantipyrine, which is metabolized to remove the methyl groups to produce carbon dioxide. After oral administration of isotope 14C-labeled aminopyrine, exhaled CO2 samples were collected at 2-hour intervals, and the function of hepatic cytochrome P450 enzymes was reflected by measuring CO2 in exhaled breath. This test reflects the function of microsomes in the liver, i.e., the function of viable liver tissue, and can reflect the metabolic function of hepatocytes more sensitively and accurately reflect the inflammation, necrosis and fibrosis of hepatocytes, which can be used to judge the prognosis of patients. ABT values are significantly lower in patients with cirrhosis, and can be used for the diagnosis of liver failure if combined with clinical biochemical indicators and Child-Pugh classification. ABT values in patients with post-hepatitis cirrhosis are significantly correlated with Child-Pugh classification and can reflect the functional reserve of the liver to some extent and be used for patient prognosis. wojcicki et al. concluded that ABT is more sensitive than lidocaine metabolism test in staging of cirrhosis. The results of monitoring ABT in patients undergoing portal vein shunt showed that those who survived more than one year after surgery had significantly higher ABT values than those who died within one year. And daily monitoring of ABT in liver transplant patients can predict acute rejection better than other liver function tests. However, the use of ABT as a means of reflecting liver reserve capacity also has its limitations. Cytochrome P450 can be induced to activate or inhibited by many internal and external factors, such as smoking and drugs, which indirectly affect ABT results. 4. Oral glucose tolerance test Patients with liver disease are prone to abnormal glucose tolerance, which may be due to ① destruction of hepatocytes and decrease in the number of insulin receptors; ② decreased activity of glycogen synthase, glucokinase, etc. and impaired glucose utilization; ③ peripheral tissues are insensitive to insulin. The state of mitochondrial energy metabolism and the ability of glycogen synthesis in hepatocytes can be reflected by the graphical pattern of the glucose tolerance test. Some studies have also used it for the evaluation of risk after hepatectomy. For example, patients with P-shaped glucose tolerance test curves are feasible for hepatectomy and recover smoothly after surgery, while those with L-shaped curves are poorly tolerant of surgery and prone to liver failure after surgery. 5.Glucagon loading test (GI) The liver is the main target organ of glucagon. Glucagon regulates the metabolism of sugar, fat and protein by stimulating the synthesis of cAMP in hepatocytes. By measuring the change of cAMP concentration in blood after glucagon stimulation, it can indirectly reflect the status of liver function. For example, in patients with cirrhosis, after glucagon loading, the blood glucose regulation ability is obviously weakened, and the difference between peak blood glucose concentration and basal concentration can reflect the status of liver function with patients with cirrhosis. 6, 14C a methadexate breath test 14C a methadexate oral absorption of human blood, in the hepatocyte slide endoplasmic reticulum (microsomes) can be added by the monooxygenase system, namely cytochrome P450, nicotinamide adenine dinucleotide phosphate, cytochrome P450 reductase to its O-position demethylation reaction, formaldehyde, the latter continue to oxidation to 14C02 through the lungs out of the body, and finally by The rate and amount of 14CO2 excretion can reflect the activity of the hepatocyte oxygenase system. Therefore, the 14C-methadrene breath test can detect the oxidative function of the monooxygenase system and reflect the structure, quantity and function of the endoplasmic reticulum of the relevant hepatocyte organelles, which in turn reflects the survival status of hepatocytes. It has been measured using Breath-Mat breath mass spectrometry in normal subjects and patients with cirrhosis, and it was confirmed that the test can instantly reflect the hepatocyte reserve and compensatory status, and the results obtained are fully quantified data, which provide quantitative data indicators for the evaluation of liver function in the perioperative period in patients with partial hepatectomy in clinical practice. The mean liver volume of Child A, B and C groups were (1092±276) cm2, (868±162) cm2, (652 ±76) cm2 (P<0.001) [8]. In contrast, surgical clinical studies have found that the minimum residual liver volume correlates with liver reserve function. When the liver reserve function is good, liver failure does not occur even if the remaining volume is small, and conversely, liver failure may occur even if more liver is preserved. Therefore, accurate assessment of the remaining volume of the liver is a matter of accurate preoperative estimation of liver reserve function. In normal individuals, 70% of the liver can be removed, whereas in those with cirrhosis, generally no more than 50% of the liver volume can be removed. Therefore, preoperative residual liver volume determination can help guide surgical treatment selection. In particular, some studies have evaluated liver volume and Child classification in combination for surgical treatment selection. Shirabe found that all patients who died of postoperative liver failure had a residual liver volume of <250 ml/m2. Some authors have combined Child-Pugh classification, ICG clearance rate and liver volume measurement for the guidance of hepatic resection in primary liver cancer, but the amount of residual liver volume as a safety line is still controversial and needs to be understood through further studies. 2.Functional liver volume measurement Desialoglycoprotein receptor (ASGPR) is a specific receptor that exists on the surface of human and mammalian hepatocytes. ASGPR is recognized by technetium-labeled desialoglycoprotein galactosyl human serum albumin (technetium galactosyl human serum albumin, 99m Te-GSA) as a ligand for ASGPR and can be detected by single photon emission computed tomography (single-photon emission computed tomography, SCT). The ligand of ASGPR can be measured by single photon emission computed tomography (SPECT) scan to reflect the functional liver volume. This technique was found to be more relevant for preoperative risk assessment and prediction of postoperative complications than liver volume measurement.Kokudo et al. studied Child-Pugh score, ASGPR blood contouring rate, ASGPR liver 15 min uptake rate, ICGR15, ASGPR concentration, whole liver ASGPR volume, liver parenchymal volume, resection Substance fraction, intraoperative bleeding, residual liver ASGPR volume, etc. It was found that only the residual liver ASGPR volume was relevant in predicting postoperative liver failure, and the incidence of postoperative liver failure was 100% when it was below 0.05 mmol/L. IV Other assays for liver reserve function In addition to the above assays in clinical application, there are various liver reserve function analysis methods that have been clinically However, these methods have not been widely used in clinical practice due to various reasons (such as economy or simplicity of operation). The accurate assessment of liver function is still a hotspot and a difficulty in clinical research, especially because most patients with liver cancer have cirrhosis, and there is still no ideal method for preoperative assessment of cirrhotic liver function. In addition to the aforementioned ICG test for surgical risk assessment, European researchers have conducted more studies on portal vein pressure measurement and noninvasive measurement of liver fibrosis, which may also play a role in the assessment of liver function in cirrhosis. (i) Portal vein pressure measurement Bruix was the first to detect changes in portal pressure in patients with cirrhosis and concluded that portal pressure may reflect to some extent the degree of liver fibrosis and parenchymal damage. Based on the level of portal pressure, it can guide the choice of surgical treatment in clinical practice. They concluded that preoperative measurement of hepatic venous pressure or hepatic venous pressure gradient could reflect the portal pressure in the liver, and confirmed that when the hepatic venous pressure gradient (HVPG) was ≥10 mmHg, patients had a significantly higher chance of irreversible liver failure after hepatectomy. For this reason, in the BCLC staging developed by the European Association for the Study of Liver Cancer, the measurement of portal pressure is used as an important basis for the selection of treatment for hepatocellular carcinoma (b) Assessment of liver fibrosis The occurrence of liver failure after liver surgery is closely related to the activity of hepatic hepatitis and the degree of fibrosis. It has been confirmed that both are closely related to the occurrence of postoperative liver failure. The degree of liver inflammation as well as liver fibrosis is still difficult to measure with more objective indicators. Changes in existing liver function indicators, such as transaminases, do not fully reflect the inflammatory status of the liver and the degree of fibrosis in the liver itself. Some studies have used histological inflammatory grading of the liver to predict the possibility of postoperative liver failure, but it is more difficult to obtain non-tumorigenic liver tissue preoperatively. Some recent studies have reported that some indicators reflect both the degree of hepatic hepatitis activity and the degree of liver fibrosis, and thus may be better predictors of the development of postoperative liver failure. For example, serum type IV 7s collagen (7s collagen), whose elevated concentration in blood is closely associated with the occurrence of postoperative hepatic encephalopathy and irreversible thoracic and ascitic fluid. And when 7s collagen was ≥12 ng/mL, all patients died from postoperative liver failure. And also studies have combined conventional serological tests to form fibrosis indices for the noninvasive assessment of liver fibrosis. Since 2001, more than 9 diagnostic models of liver fibrosis have been published in leading international journals, such as Fibrotest, Forns index, fibrosis likelihood index, European liver fibrosis model, and Shanghai liver fibrosis group model. Most of the parameters involved in these models are currently commonly used hematological tests in laboratories, and their combined application is of clinical application for the diagnosis of liver fibrosis (cirrhosis) after HBV and HCV infection. Their non-invasive properties are of great interest, but the correlation of such indices with the degree of fibrosis, with the reserve of liver function, and whether they can be used for the prediction of risk after liver cancer surgery need to be further explored and studied.