Hepatectomies are performed for the treatment of hepatic tumors and livingdonor liver transplantation. The success of liver resection relies on the remnant liver's ability to regenerate after major tissue loss. Despite appropriate liver remnant volume after resection ensures the liver's ability to regenerate, regeneration progresses at variable ratesin patients.

Many researches have established a relationship between the gut microbiome and patients with liver disease such as liver cirrhosis, alcoholic liver disease and obesity related liver diseases. These liver disorders are associated with bacterial overgrowth, dysbiosis, and increased intestinal permeability. However, the relationship between hepatectomy and microbiota has not been fully investigated.

The measurement of small-molecule metabolites has been an integral part of clinical practice including the familiar clinical standards like glucose and creatinine. Metabolomics, however, is able to measure all the metabolites at once. It is possible to get a far more comprehensive picture of what is happening to a patient's physiology or metabolism. Although gut microbiota has been shown to be related to liver disease and liver regeneration. Obtaining a more comprehensive analysis by identifying not only the microbial composition but also the metabolites will be more insightful.

Many routine perioperative aspects of surgical care can impact the state of the microbiome and therefore can impact clinical outcomes, like bowel preparation and antibiotics. Potential factors affecting the gut microbiota also include perioperative manipulation, stress released hormones, and opioids. Maintenance of proper anesthetic depth is beneficial to attenuate surgical stress. General anesthesia including volatile anesthetics and opioids, is associated with altered gut microbiota which might in turn affect liver regeneration. In this regard, perioperative care such as anesthesia, is one of the key points for the success of a liver resection. However, which anesthetic method is preferable regarding postoperative outcome or recovery is controversial.

In this study, the study population will include liver tumor resection and living donor hepatectomy. We aimed to 1) identify the relationship of hepatectomy and changes of gut microbiota and metabolomics. 2) investigate the impact of different anesthetic methods on the interaction of gut microbiota and metabolomics.

Inclusion Criteria:

1. Expected to receive hepatic tumor resection in National Taiwan University Hospital, age between 20 and 75 years old.

Exclusion Criteria:

1. Previous use of antibiotics within four weeks.
2. Previous gastrointestinal surgery.