Comparison of 6-min walk test distance vs. estimated maximum oxygen consumption for predicting postoperative pulmonary complications in patients undergoing upper abdominal surgery: a prospective cohort study.

"Declarations Ethics approval and consent to participateThis clinical study was conducted in accordance with the principles of the Declaration of Helsinki and approved by the ethics committee at Huadong Hospital (2019K015). Written, informed consent was obtained from all participants prior to enrollment in the study. Consent for publicationAll authors approved the version of the manuscript to be published. Competing interestsThe authors declare that they have no competing interests. Competing interests The authors declare that they have no competing interests."

"Funding This study was supported by the project of the National Natural Science Foundation of China (82271286), the National Key R&D Program of China (2018YFC2002000), the High-level Local University Construction Project of Shanghai Medical College (FNDGJ202212), the project of Science and Technology Commission of Shanghai Municipality (20Y11900200), the natural Science Foundation of Tibet Autonomous Region (XZ2022ZR-ZY26(Z)), the Shanghai Municipal Health Commission (2020YJZX0119), the Shanghai Municipal Commission of health (202,140,515), and the Clinical Culture Project of Huadong Hospital (2019lc002)."

"The present study is a prospective diagnostic study was conducted in a single center from March 2019–May 2021 at Huadong Hospital Affiliated with Fudan University, Shanghai, China. The inclusion criteria were as follows: (i) Patients scheduled for elective major upper abdominal surgery with an expected operation duration of at least 2 h and (ii) age ≥ 18 years. The main exclusion criteria (ATS statement ; Hammal et al. ) were as follows: (i) failure to perform 6MWT due to the limitation of movement or complications, (ii) current treatment with β-blockers, (iii) unstable angina or myocardial infarction during the previous month, (iv) systolic blood pressure > 180 mmHg or diastolic blood pressure > 120 mmHg or heart rate > 120 beats/min at rest, and (v) inability to cooperate with 6MWT because of communication disorders or mental disease. All patients provided written informed consent before enrolment in the study. This clinical study was conducted in accordance with the principles of the Declaration of Helsinki and approved by the ethics committee at Huadong Hospital (2019K015). The study was registered with the Chinese Clinical Trial Registry (ChiCTR1900022772)."