Plasma NFL concentrations were measured preoperatively and 1 day postoperatively.~Secondary endpoints:MMSE (Mini-Mental State Exam) and CAM (Confusion Assessment Method) is conducted to check the subjects' baseline cognitive function preoperative day and 0 to 7 postoperative day twice a day to assess whether delirium occurs.
The aim of this study is to conduct a prospective, single-center randomized controlled study to investigate the changes of plasma NFL concentration in patients undergoing laparoscopic surgery with mild hypercapnia, and further explore its impact on the central nervous system.