The Effect of Circadian Clock System on Perioperative Cognitive Function of Elderly Patients

Postoperative cognitive dysfunction (POCD) is a common postoperative complication in patients aged 65 and above. It refers to the cognitive function changes such as memory decline and attention loss after anesthesia and surgery. In serious cases, people may also experience personality changes and decline in social behavior ability, which will develop into irreversible cognitive impairment.Some studies reported that 25.8% of elderly patients presented POCD one week after non-cardiac surgery, and the incidence at 3 months after surgery was still 9.9%, which could increase the mortality in the first year after surgery.In recent years, studies have also proved that POCD is associated with patients' inability to perform their original jobs after non-cardiac surgery.Postoperative cognitive dysfunction seriously affects the clinical outcome, in addition to medical costs and other issues will bring an impact on the society and family.With the aging of the population, how to prevent cognitive dysfunction in elderly patients is a major challenge for perioperative management.There is a certain correlation between circadian rhythm and the dosage of general anesthesia, and postoperative sleep disturbance may be related to the effect of anesthesia and surgery on circadian rhythm.Preoperative sleep deprivation is known to be an independent risk factor for postoperative cognitive dysfunction (POCD), but the circadian mechanisms involved after general anesthesia are not yet clear