BACKGROUND: The incidences of surgery-field disorders such as femur neck 
fracture and colorectal cancer in elderly persons have increased with the rapid 
aging of society. In such patients, postoperative delirium is also frequent. 
Patients should be generally assessed from the aspect of both physical and 
mental conditions in order to predict a high-delirium risk group. If so, 
delirium may be prevented more efficiently. In this study, we investigated 
whether the early detection of postoperative delirium in elderly patients is 
possible using a simple, useful behavior-assessing scale, the NEECHAM Confusion 
Scale, and a method for comprehensively evaluating elderly persons' stress 
related to surgery, E-PASS.
METHODS: The subjects were 160 patients aged more than 75 years who underwent 
surgery. Among them, three patients had vascular surgery-field disorders, 67 had 
orthopedic-field disorders, and 90 had digestive surgery-field disorders. To 
comprehensively evaluate surgery-related stress, E-PASS was employed. In 
addition, we assessed recognition, activities of daily living (ADL), and the 
quality of life (QOL). For delirium diagnosis and severity assessment, we used 
the NEECHAM Confusion Scale. The cut-off value of the NEECHAM score was 
established as 20 points, and patients showing values less than this after 
surgery were regarded as having postoperative delirium. Evaluation was performed 
until 10 days after surgery.
RESULTS: Postoperative delirium was noted in 54.7% of the subjects. There was a 
decrease in the NEECHAM score between the first and fourth postoperative days, 
but it gradually increased thereafter. Both uni- and multivariate analyses 
showed that postoperative delirium was associated with an advanced age (more 
than 80 years), low preoperative NEECHAM and MMSE scores, the preoperative QOL, 
and E-PASS. In groups showing an MMSE score of less than 25 or a preoperative 
NEECHAM score of less than 27, the incidence of postoperative delirium was 76%.
CONCLUSION: The results suggest that E-PASS and the NEECHAM score facilitate 
assessment of the risk of postoperative delirium in elderly patients, 
contributing to early prevention/treatment.