The Effect of General Anesthesia with Remimazolam and Propofol on Rhythmic State and Cognitive Function

Benzodiazepines are one of the most important and commonly used intravenous sedatives in the perioperative period. However, benzodiazepines are often associated with a variety of side effects, including respiratory depression, cardiovascular depression, excessive sedation, delayed recovery, disturbance of consciousness, dizziness and nausea, postoperative delirium, and postoperative cognitive impairment. Remimazolam is a new type of benzodiazepine anesthetic drug. It can be rapidly hydrolyzed into inactive carboxylic acid metabolites by widely existing carboxylesterases in the human body. Therefore, it has the characteristics of fast onset, fast metabolism, little impact on liver and kidney function, and little inhibition of respiratory circulation. However, as a benzodiazepine, remimazolam has little effect on postoperative cognitive function. Biorhythms are currently a hot topic in medical research. Many organisms, including mammals, have the suprachiasmatic nucleus (SCN), a circadian clock pacemaker located in the hypothalamus, which drives the rhythms of activity and rest, fasting and eating, body temperature and hormones to synchronize to 24 hours. Many anesthetic drugs, such as propofol, dexmedetomidine, and volatile anesthetic drugs such as sevoflurane and desflurane, interfere with the expression of circadian rhythm genes in mammals. For example, the expression of rhythm genes per1 and per2 in supratasmatic nucleus of rats injected with a single dose of propofol is down-regulated, and irregular resting activity rhythm is observed in patients undergoing colonoscopy under anesthesia with propofol. The circadian period of patients undergoing general anesthesia is obviously advanced, and the disturbance of circadian rhythm is an important feature of postoperative sleep disorders. However, sleep disorders can aggravate postoperative delirium and postoperative cognitive dysfunction, and related rhythm genes such as Dbp participate in the plasticity of the hippocampus, so the interference of anesthesia drugs on the biological rhythm of the body may be an important cause of postoperative cognitive dysfunction. Since propofol is commonly used in clinical intravenous anesthesia, this study intends to compare the effects of remimazolam and propofol on patients' activity rest rhythm and their effects on learning and memory functions.