Differential Effects of Various Anesthetic Agents on Cognitive Function in Patients With Alzheimer's Disease

Patients with mild-to-moderate Alzheimer's disease who are scheduled to have elective
noncardiac, nonneurologic, nonvascular surgery will be recruited at the Massachusetts General
Hospital (MGH). The study will first be introduced to patients at their preoperative surgical
clinic appointment by his/her surgeon. If patients are interested in participating, they will
notify their surgeons, and subsequent recruitment will take place at the MGH Pre-Admission
Testing Area (PATA), a clinic for preoperative evaluation and medical optimization. Patient
contact and recruitment, however, will only proceed with permission from (1) the patient
him/herself and (2) the patient's surgeon. Per the Partners Human Research
Committees-approved criteria, if patients do not have capacity for clinical-decision making
but express a willingness to participate in the study, a surrogate (i.e. healthcare proxy
and/or family member) co-signature will be required on the consent form. On the day of the
subject's surgery, the anesthesia team will be allowed to choose one of four anesthetic
options (i.e. propofol anesthesia, isoflurane anesthesia, sevoflurane anesthesia, or
desflurane anesthesia) based on clinical preference and appropriateness. The research team
will be blinded to the anesthetic to which subjects are assigned. Finally, patients will be
followed for one year post-operatively with a battery of cognitive tests to determine
differences in cognitive trajectory.

Inclusion Criteria:

- Patients diagnosed with Alzheimer's disease (AD) per Diagnostic and Statistical Manual
of Mental Disorders, Fourth Edition (DSM-IV) criteria.

- Patient recruitment permission granted by his/her surgeon

- Requires general anesthesia for elective noncardiac, nonneurologic, nonvascular
surgery.

Exclusion Criteria:

- History of neurologic or psychiatric disease (i.e. stroke, psychosis, etc.)

- Non-native English speaker

- Severe visual or auditory disorder

- Sensitivity to sulfites (some propofol formulations at MGH may contain sodium
metasulfite).

- Asthma (sulfite sensitivity is seen more frequently in asthmatic than in non-asthmatic
people).