[Change of the cognitive function after open heart surgery].

The changes of cognitive function after open heart surgery was examined using the Hasegawa's Dementia Scale (max. 30 points) in 47 patients with average age of 61.7 years. The patient's score was obtained preoperatively, and 1st and 7th postoperative days. Patients with postoperative scores above 24 points were classified as Non-Decline group, and those below 23 points as Decline group; comparative analyses were done on the relationship between various perioperative factors on both groups. Anesthesia was induced with low-dose fentanyl and isoflurane-nitrous oxide in oxygen. The average operating time was 331 minutes, and the cardiopulmonary bypass time was 108 minutes with normothermia. There were 31 Non-Decline cases, and 16 (34%) Decline cases on the 1st and 5 (10 %) on the 7th postoperative day. The largest decrease in the Decline group was seen on the 1st postoperative day, and there were 4 cases of dementia. The factors in which a significant difference was observed between the 2 groups were age, amount of transfusion, extubation time, preoperative complications and postoperative cardiac index, and these was not related to the operation or ECC time. Moreover there were high incidences of postoperative complications, especially LOS, in the Decline group. It was concluded that one of the largest contributing factors of abnormality of the cognitive function postoperatively was age, and other factors such as pre- and postoperative general conditions of the patients, especially cardiac function, might also be related. The length of hospitalization in the cases of decreased cognitive function was longer.