Surgical stress and transient postoperative psychiatric disturbances in aged patients studied using the Yamaguchi University Mental Disorder Scale

Abstract

Psychiatric disturbances often occur in aged patients after surgery, but there is no easy or precise method of predicting their occurrence. We devised an easy mental test, the Yamaguchi University Mental Disorder Scale (YDS), based on the surgical perspective. Using both this new method and the Hasegawa mental disorder scale (HDS), we examined 106 patients who had undergone general anesthesia. HDS only was used in 70 cases, while 36 cases were examined by the newly devised YDS and were then compared with the findings obtained by HDS. On the HDS examination, factors affecting postoperative psychiatric disturbances were, in order of frequency: entering the ICU, amount of bleeding, and duration of surgery. Aged patients who experienced severe surgical stress had a higher risk of developing transient postoperative psychiatric disturbances. On the YDS examination, the relationship between surgical stress and transient postoperative psychiatric disturbances was clearly indicated, as was the case with HDS. Postoperative delirium was seen in a significant proportion of patients with low preoperative scores on YDS (P<0.05), while no significant difference was observed between the mean preoperative scores on HDS and postoperative delirium. In the preoperative evaluation using YDS, postoperative delirium was found to be predictable, and YDS is thus considered to be a more valuable tool in managing aged patients.