As a newly developed subject, metabolomics can detect accurately and quantitatively small molecule metabolites such as proteins, carbohydrates and lipids from plasma, tissue and even single cell, which aims to analyze systemic dynamic change during physiological and pathological processes, and thus reveals certain reactions that whole organism responds to specific stimulation.

Colorectal cancer is one of common gastrointestinal tumors, whose morbidity rate tends to increase in recent years for modern diet and life style, and colectomy serves as one standard treatment for it. Under total stimulation of surgical operation, general anesthesia and mechanical ventilation, a series of stress reactions happen complicatedly to colorectal patients during anesthesia-ventilation process. Without timely recognition and management of adverse reactions, side effects like hypoxemia, hemorrhage, inflammation, and even death will happen intraoperatively or postoperatively.

With different metabolomics methods applied to collect, detect and analyze blood samples, metabolomics provides an innovatory approach to elucidate systemic response during anesthesia-colectomy process with multi-factors included. By analyzing and comparing dramatic alteration of small molecule metabolites in colorectal cancer patients' or healthy controls' plasma in this project, data can reflect the influence of certain disease (colorectal cancer), anesthetics and mechanical ventilation on colorectal patients with colectomy, which is helpful for prevention and treatment of intraoperative and postoperative complications.

Nowadays, more and more attention are paid to system biology and its relative techniques, such as gene sequencing，nuclear magnetic resonance， mass spectrometry and so on. As a newly developed subject, metabolomics can detect accurately and quantitatively small molecule metabolites such as proteins, carbohydrates and lipids from plasma, tissue and even single cell, which aims to analyze systemic dynamic change during physiological and pathological processes, and thus reveals certain reactions that whole organism responds to specific stimulation.

Colorectal cancer is one of common gastrointestinal tumors, whose morbidity rate tends to increase in recent years for modern diet and life style, and colectomy serves as one standard treatment for it. Under total stimulation of surgical operation, general anesthesia and mechanical ventilation, a series of stress reactions happen complicatedly to colorectal patients during anesthesia-ventilation process. Without timely recognition and management of adverse reactions, side effects like hypoxemia, hemorrhage, inflammation, and even death will happen intraoperatively or postoperatively.

With different metabolomics methods applied to collect, detect and analyze blood samples, metabolomics provides an innovatory approach to elucidate systemic response during anesthesia-colectomy process with multi-factors included. By analyzing and comparing dramatic alteration of small molecule metabolites in colorectal cancer patients' or healthy controls' plasma in this project, data can reflect the influence of certain disease (colorectal cancer), anesthetics and mechanical ventilation on colorectal patients with colectomy, which is helpful for prevention and treatment of intraoperative and postoperative complications.

Inclusion Criteria:

• Colorectal cancer patients inclusion criteria: undergo elective colectomy with general anesthesia and mechanical ventilation lasting for > 3.5 hours; classified as physical status I to III according to the American Society of Anesthesiologists Physical Status Classification System; Written informed consent is approved.
• Healthy controls inclusion criteria: volunteers with regular physical examination in nearly three years；without chronic disease; without recent infection in three months; Written informed consent is approved.

Exclusion Criteria:

• Distant metastases; hemodilution with massive fluid supply; recent anaesthetics or mechanical ventilation treatment；children；women during pregnancy or lactation; being involved in other clinical subjects.

colorectal cancer patients and healthy controls