Author ORCID Identifier

http://orcid.org/0000-0003-3732-3463

Year of Publication

2016

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Nursing

Department

Nursing

First Advisor

Dr. Debra K. Moser

Abstract

Postoperative cognitive dysfunction (POCD) occurs frequently in individuals undergoing major surgery with general anesthesia. POCD adversely affects morbidity and health-related quality of life. Derived electroencephalographic (EEG) monitoring is utilized to guide the anesthesia provider in titration of volatile anesthetics. POCD has been associated volatile anesthetic neurotoxicity. EEG monitors are known to reduce a patient’s total cumulative dose exposure to volatile anesthetics. There is currently little evidence to support utilization of EEG monitors as a guide to reduce the incidence of POCD.

The purpose of this dissertation was to develop and test a technique of general anesthesia, delivered by anesthesia providers and guided by the Bispectral Index™ (BIS) system EEG monitor. This technique was designed to reduce cumulative volatile anesthetic exposure and reduce cognitive decline. Prior to testing the intervention, preliminary work was conducted resulting in a review of evidence for current concepts in the mechanism of volatile anesthetics and their relationship with POCD. Based on information from these manuscripts, a randomized, controlled study was conducted to test the effects of BIS guided anesthetic technique on outcomes of middle aged patients undergoing impatient major surgery.

Eighty-eight patients scheduled for major inpatient surgery were randomized to a BIS guided anesthetic, or to usual care control. Although not in every cognitive domain, BIS guidance resulted in superior and not inferior performance in cognitive testing.

The third manuscript documents predictors of cognitive decline. This was a secondary, planned data analysis of the previous prospective, randomized controlled trial. Consistent predictors of cognitive decline through the study phases were older age, lower income, and lower education. In addition to these, tobacco abuse is a significantly predictive characteristic.

Further research should be focused on at risk cognitive domains, as well as, exploring other anesthetic regimens to avoid cognitive decline.

Digital Object Identifier (DOI)

https://doi.org/10.13023/ETD.2016.496

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