[Changes in intellectual function during perioperative period evaluated by Hasegawa's Dementia Scale].

In 190 patients, we studied changes in intellectual status during perioperative period using Hasegawa's Dementia Scale (HDS-R), and analyzed preoperative, intraoperative, and postoperative risk factors. HDS-R is one of the most popular scoring tests for evaluating dementia or delirium. Risk factors impairing preoperative score were aging, and preoperative complications including cerebral vascular disease, old myocardial infarction, arrythmia, and diabetes mellitus. Risk factors impairing postoperative score were, in addition to above-mentioned factors, hypoproteinemia and postoperative stressful conditions such as prolonged fever, pain, bed rest, and naso-gastric tube. In the patients who showed postoperative score deterioration, the incidence of old myocardial infarction, hypertension, and postoperative stressful conditions was significantly greater. In the patients who showed postoperative score improvement, local anesthesia including epidural and spinal anesthesia was used more often. In conclusion, aging or preoperative complications such as cerebral vascular disease, old myocardial infarction, arrythmia, and diabetes mellitus are high risks for the development of postoperative dementia and delirium under general surgical procedures and general anesthesia. Intraoperative management with patients awake using local anesthesia and postoperative stress-less conditions are important to avoid postoperative dementia.