Anesthetic Depth and Postoperative Delirium Trial - 2

N/ACompletedNCT01983384

University of California, San Francisco205 enrolled

Overview

Recent limited evidence suggests that anesthetic depth may influence postoperative cognitive outcomes, however, the mechanism between this association is unclear.

Recently, it has been proposed that use of a processed electroencephalogram (EEG) monitor during surgery may be associated with a lower rate of postoperative delirium. In fact, some suggest that older patients undergoing surgery should routinely be monitored with an anesthetic depth monitor to allow the titration of anesthetics or sedation medications to lighter levels to promote better postoperative cognitive outcomes. Recent studies, including preliminary results from our group, have demonstrated electroencephalogram (EEG) suppression to be an independent risk factor for postoperative delirium. Prior studies that have focused on risk prediction have shown age and prior cognitive impairment to be the most consistent risk factors for postoperative delirium. However, as of yet, no clinical trial has identified a relationship whether use of processed EEG monitor resulted in a reduction of incident postoperative delirium through a reduction in EEG suppression, with proper consideration of patients' baseline cognitive status as a potential moderator. Additionally, use of anesthetic depth monitor to keep patients' anesthetic depth above a specified value has never been validated or proven to be feasible or safe. Accordingly, the investigators plan an exploratory study to: 1) determine whether the use of processed EEG to keep anesthetic depth above a specified level, results in a reduction in EEG suppression when compared to standard anesthetic care, 2) to determine whether preoperative level of cognitive function moderates the effect of group assignment on EEG suppression, and 3) to determine the feasibility and safety of using processed EEG-guided to keep patients' anesthetic depth above a specified value. A secondary aim was to determine the effect size for the intervention to reduce postoperative delirium for subjects with and without preoperative cognitive impairment for a future trial.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Enrollment

205

Conditions

Delirium Cognitive Disorders

Interventions

Processed EEG-guided anesthetic depthOTHER

Investigators will undertake a randomized control trial in a cohort of older patients undergoing major non-cardiac surgery to receive either a control vs. an intervention of anesthesia as determined by a processed electroencephalogram

Eligibility

Sex: ALLMin age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * 65 years and older of age undergoing non-cardiac surgery, requiring hospital stay of 2 or more days. Exclusion Criteria: * patients who are not fluent in English or cannot provide informed consent * patients who may not tolerate either light or deep anesthesia (history of heart failure, coronary artery disease, substance abuse) * history of intraoperative recall or awareness during anesthesia * pathologies of the brain which may affect EEG monitoring * patients who are anticipated to have consecutive surgery within 3 days of first procedure * patients who have had surgery with general anesthesia in the past 30 days

Locations (1)

University of California, San Francisco Medical Center

San Francisco, California, United States

Outcomes

Primary Outcomes

Intraoperative EEG Suppression

Intraoperative EEG suppression will be measured by processed EEG monitor

Time frame: Patients will be monitored by processed EEG intraoperatively, for the duration of surgery

Secondary Outcomes

Preoperative level of cognitive function

Level of cognitive function will be measured by Telephone Interview for Cognitive Status

Time frame: Up to one week before surgery

Patient intraoperative awareness and recall

Intraoperative recall and awareness measured using modified Brice questionnaire (2 question survey - each answered with a yes or no, with additional checkboxes for applicable descriptions of events recalled \[e.g. "Hearing voices," "Feeling pain," etc\]) Patients answering yes to either question are classified as accidental awareness after general anesthesia (AAGA), which is regarded as an intraoperative adverse event.

Time frame: Intraoperative recall and awareness will be measured within 72 hours after end of surgery

Patient movement

Patient movement will be recorded from the anesthesia record

Time frame: During surgery

Intraoperative systolic and diastolic blood pressure

Intraoperative systolic and diastolic blood pressure will be continuously downloaded onto a computer for subsequent analysis. Increases or decreases above the preoperative baseline measurements will be measured and recorded from the medical record

Time frame: During surgery

Intraoperative heart rate

Intraoperative heart rate will be continuously downloaded onto a computer for subsequent analysis. Increases or decreases above the preoperative baseline measurements will be measured and recorded from the medical record

Data from ClinicalTrials.gov

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