Observational study on the predictive value of the BAMCOG and cortisol levels for the incidence of Postoperative Delirium/Postoperative acute encephalopathy measured by the MoCA and the DeltaScan in patients who undergo Aortic Valve Replacement surgery

The mean age of surgical patients is rising worldwide and this is associated
with more multi-morbidity. Especially geriatric patients who undergo surgery
have a higher risk to develop Postoperative Cognitive Dysfunction or a
Postoperative Delirium, which leads to higher morbidity and mortality after
surgery and this leads to higher healthcare costs.

A delirium is an acutely disturbed state of mind characterized by restlessness,
illusions, and incoherence, occurring in intoxication, fever, and other
disorders and can fluctuate over time. The hypoactive delirium, the most common
type of delirium, is hard to recognize compared to the active delirium that is
expressed by restlessness and agitation.

Postoperative cognitive dysfunction is defined as a new cognitive impairment
arising after a surgical procedure. Its diagnosis requires both pre- and
postoperative psychometric testing. Its manifestations are subtle and manifold,
depending on the particular cognitive domains that are affected, and therefore
hard to recognize too.

To assess preoperative cognitive function in large groups of patients, we need
a simple and quick tool to screen. In this study, we use the BAMCOG, which is a
tool with 3 short games played on a tablet that can give us information about
cognitive functioning. When writing this new study protocol, a validation study
in which the BAMCOG is validated against the MoCA is running.

Beside the BAMCOG, another instrument will be investigated. The DeltaScan is an
EEG delta waves measurement to identify patients with a (hypoactive) delirium.
Delta waves are slow brainwaves that have been seen in sedated patients and
even in patients with an active or hypoactive delirium. A study of Kimchi et
al. studied whether routine clinical EEG findings, including slowing, are
correlated with delirium severity in a heteroge- neous population with various
causes ofaltered mental status and found that generalized slowing on routine
clinical EEG strongly correlates with delirium and may be a valuable biomarker
for delirium severity (OR 7.4, 95% CI 3.8-14.4).

A lot remains unclear about the biological mechanisms in the development of a
delirium after surgery, although in literature are directions that inflammatory
reactions and the neuro-endocrine system play an importante role. That is the
reason for investigating the relation between cortisole levels in blood, saliva
and sweat and the development of postoperative acute encephalopathy.

1. The predictive value of the BAMCOG for developing postoperative
delirium/postoperative acute encephalopathy in patients who underwent AVR
surgery
2. Concurrent validation of the BAMCOG with the MoCA
3. The relation between cortisol levels in blood, saliva and sweat and the
development of postoperative delirium/postoperative acute encephalopathy.

Measurements

Preoperative:
At the outpatient clinic: BAMCOG, MoCA and DeltaScan
At home: 2 saliva tests
Time: 1 hour.

Day of surgery:
Sweat, saliva and blood sample (2x/day)

Postoperative:
Day 1, 3 and 7 after surgery: BAMOG, MoCA, DOS score (Delirium Observation
Score) and DeltaScan (3x/day)

Extra time per day: 1 hour
Total extra time: 4 hours (of which 3 days in hospital after surgery)

There are no relevant risks associated with participation on this study except
extra time load.