Anesthesia Depth Increases the Degree of Postoperative Dementia, Delirium, and Cognitive Dysfunction
Status:
Completed
Trial end date:
2017-05-08
Target enrollment:
Participant gender:
Summary
Anesthetics and anesthesia are suspicious to induce dementia or aggravate preexistent
cognitive deficits with or without evoking postoperative delirium. In animal trials various
anesthetics induce increased levels of misfolded amyloid beta and protein tau, the molecular
substance of pathophysiologic brain tissues of demented patients. The amount of those markers
seems to correlate well with the degree of dementia [1]. In contradiction, a single study
indicates that the incidence of postoperative cognitive deficit (POCD) decreases if hypnotic
depth is deep [2]. Unfortunately the study did not sum up the amount of anesthetic drug load,
since this would have clarified if the amount of anesthetics used is associated to POCD and
dementia. Another possibility is that stress and noxious stimulation induced by light
anesthesia results in POCD, whereas deep anesthesia protects from it or inhibits implicit
memory.
The investigators' prospective randomized trial is underway to verify the impact of
anesthetics and narcotic depth upon grade of dementia and incidence of early postoperative
cognitive dysfunction on postoperative day 1 as well as the incidence of delirium within a 90
day period.
The investigators' hypothesis is that the incidence of POCD and delirium and the degree of
early cognitive dysfunction is less when anesthetic and vasoactive drug load is less in the
BIS- guided anesthesia group with the superficial but sufficient anesthesia level.