Interventional Study of Early Postoperative Cognitive Dysfunction in Elderly Patients Undergoing General Anesthesia

The main purpose of this study is to determine the incidence of early postoperative cognitive dysfunction in elderly patients and its time course.

This study will first evaluate the preoperative cognitive function of elderly patients based on several criteria including complete patient history, laboratory and instrumental exams, and the following measures in order to identify conditions and pathologies that may influence cognitive function.

• Mini Mental State Examination
• Geriatric Index of Comorbidity
• Geriatric Depression Scale

The following neuropsychological tests will be performed on the same day within 7 days of surgery (baseline):

• Trail Making Test B-A
• Digit Span
• Digit Symbol Substitution Test

The three cognitive function assessments will be repeated at the following postoperative time points and the change from the preoperative baseline to each time will be evaluated:

• Day 2 (time point 1)
• Day 4 (time point 2)
• Between days 85 and 90 (time point 3)

If the patient seems confused before the postoperative administration of these tests, the Neecham Confusion Scale will be used to evaluate the patient for the presence of postoperative delirium; if delirium is not detected, the cognitive function tests will be administered.

This study has three specific aims:

1. To define the frequency of occurrence of early post-operative cognitive dysfunction and its time course.
2. To assess risk factors for the onset of post-operative cognitive dysfunction and possible causal factors.
3. to compare our results with those from the international literature.

Inclusion Criteria:

• Age > 65 years
• Surgery scheduled under general anesthesia, that is expected to last 90 minutes or longer for the arm experimental

Exclusion Criteria:

• A score of 20 or less on the Mini-Mental State Examination (MMSE)
• Illiteracy
• Can't understand Italian language
• Serious hearing or vision impairment not treatable
• A history of any disease of the central nervous system
• A current or past history of psychiatric illness
• A current use of major tranquilizers or antidepressants
• alcoholism or drug dependence or abuse
• Scheduled to undergo cardiac, carotid or intracranial procedures
• Not expected to be alive or available to complete testing at 90 days after surgery