6-minute walk test (6MWT) is widely used in cardiopulmonary surgery as a prognostic marker. This prospective cohort study aims to find whether 6MWT will be a good prognostic factor for patients who will undergo laparoscopic gastrointestinal surgery.The investigators will enroll patients awaiting elective laparoscopic gastrointestinal surgery in this study. After informed consent was obtained, the participants will be evaluated through 6MWT. Preoperative assessment and conditions during operation will be recorded. The investigators will analyze the correlation between preoperative 6MWT's result and outcomes after laparoscopic gastrointestinal surgery.

This is a prospective observational cohort study, which focus on the prognostic value of 6-minute walk test (6MWT) in patients who will undergo laparoscopic gastrointestinal surgery.

Enhanced recovery after surgery (ERAS) is an optimized program which help patients accelerate recovery and improve outcomes by integrating evidence-based protocols and guidelines. With the rapid development of ERAS, the preoperative clinical data of patients are paid more and more attention to evaluate the risk of perioperative complications and choose an appropriate time for surgery. A better perioperative evaluation method will lead to lower morbidity and mortality rates of postoperative complications and shorter time of hospital stay. So, it is important to find an appropriate evaluation method to predict the outcomes of patients undergoing surgery.

6MWT is a low-cost, easy to operate and well-tolerated test to evaluate exercise tolerance to predict cardiopulmonary function. It has widely used in cardiopulmonary surgery as a prognostic marker. Even though massive studies showed that decreased perioperative 6-minute walk distance (6MWD) related to postoperative complication in patients underwent cardiac or pulmonary surgery, there are only small numbers of studies with small number sizes presenting correlation of decreased 6MWD and postoperative complication in abdominal surgery. Even some studies of upper abdomen got the opposite result. Furthermore, the critical value for 6MWD is still controversial. Based on these conditions, this study was designed to investigate if 6MWT cloud be used as an accurate assessment with the prognostic value in patients who will undergo laparoscopic gastrointestinal surgery to improve the ERAS program.

The investigators decide to enroll 200 patients awaiting elective laparoscopic gastrointestinal surgery in this study at Peking Union Medical College Hospital. After informed consent was obtained, the patients will be comprehensively evaluated from demographic characteristics, complications of systems and organs, laboratory tests results, 6MWT, metabolic equivalents (METs), psychological states assessed by hospital anxiety and depression scale. Outcomes will be assessed according to the Clavien-Dindo Classification of Surgical Complications. Operative name, operation date, operative method, blood loss, situation of blood transfusion, operation time, duration of anesthesia, whether return to ICU or not (treatment time and tubulization time), drainage flow of within 24 hours after surgery will be recorded. Other outcome measures include the mortality rate within 30 days after surgery, second operation without plan, rehospitalized rate without plan, postoperative hospitalization time, patient satisfaction.

Descriptive analysis, univariate analysis, multivariate analysis and establishment of complication prediction model will be used to analyze the correlation between preoperative 6MWD and outcomes.

Inclusion Criteria:

1. Inpatient in Peking Union Medical College Hospital from January 2019 to December 2019
2. From 18 y/o to 75 y/o
3. Consent got from patients
4. Decide to take the elective laparoscopic gastrointestinal surgery in Peking Union Medical College Hospital

Exclusion Criteria:

1. Refuse to take part in the study (due to any reason)
2. ASA grade ≥ IV
3. Unable to cooperate with the study (mental disorder, disturbance of consciousness, dysnoesia)
4. Have developed unstable angina or myocardial infarction in the recent 6 months
5. HR>120 beats/min or SBP>180mm/Hg or DBP>100mmHg at resting state
6. During acute episode of asthma
7. Diseases cause severe limitation of walking, including severe lumbar spondylosis, knee osteoarthritis, lower extremity varicose veins, et al.
8. Other conditions make patients can't cooperate with 6MWT

Inpatient from 18 y/o to 75 y/o going to have elective laparoscopic gastrointestinal surgery in Peking Union Medical College Hospital from January 2019 to December 2019.