Effect of intranasal insulin on cognitive function in elderly patients after laparoscopic radical resection of colorectal cancer: a double-blind, pilot study

Interventions: insulin group (group I):Starting two days before surgery, insulin nasal drops should be administered twice a day until the day of surgery, 20U each time (0.5 ml) ;control group (group C):Starting two days before surgery, physiological saline nasal drops of 0.5 ml were administered twice a day until the day of surgery Primary outcome(s): The incidence of postoperative cognitive dysfunction Study Design: Parallel