Depth of Anesthesia on Implicit Memory

The Effect of Depth of Anesthesia on Implicit Memory

Purpose of this study is to see if different levels of anesthesia have an effect on hearing spoken words without awareness of having heard them or anxiety after surgery.

Study Overview

• Status: Completed
• Conditions: Anesthesia, General; Memory
• Intervention / Treatment: Combination product: BIS 40; Combination product: BIS 60

Detailed Description

Amnesia (lack of recall) is one of the most important goals of general anesthesia. Inadvertent free recall during a major surgical procedure is not only inhumane, but also predisposes the patient to morbidity such as post-traumatic stress disorder. Therefore, it is standard practice among anesthesiologists to inquire about free (explicit) recall during a post-anesthetic visit.

Free recall requires a functional long term memory. Historically, lack of free recall during general anesthesia has been regarded as complete absence of long term memory activity. However, recent evidence suggests that the relationship between general anesthesia and memory is more complex than previously thought.

Objectives of the proposed are twofold: (1) to test the presence of implicit memory under two different planes of surgical general anesthesia in elderly males (55-90 years old) during a uniform surgical procedure (urologic procedures via transurethral approach) (2) to compare the pre and postoperative anxiety levels as a marker of clinical significance of operational implicit memory function.

The study is divided into three phases: pre-operative, operative, and post-operative.

Pre-operative phase will consist of a cognitive function test (mini-mental state exam). This will be administered at the urology or pre-operative anesthesia clinic visit, after obtaining the informed consent of the patient.

Operative phase will start with a baseline anxiety test (Spielberger state-trait anxiety test) just before being taken to the operating room. This will be followed by playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.

Post-operative phase will have of a spoken word-stem completion test (just before discharge from the hospital) and a repeat of the anxiety test mentioned above (2 to 3 weeks post-operatively).

• Study Type: Interventional
• Enrollment (Actual): 70
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73104
      • University of Oklahoma Health Sciences Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 55 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Persons signing informed consent
• Elective general surgery for orthopedics (external or internal fixation) or urologic (transurethral)
• Literate
• Native English speaking

Exclusion Criteria:

• Hearing impaired
• History of cognitive dysfunction
• Subjects requiring post-operative sedation for any indication

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bispectral Index (BIS) 40; Target BIS 40	Combination product: BIS 40; Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively. Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room. Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered. Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia. Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.; Other Names: Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File; Combination product: BIS 60; Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively. Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room. Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered. Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia. Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.; Other Names: Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File
Experimental: Bispectral Index (BIS) 60; Target BIS 60	Combination product: BIS 40; Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively. Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room. Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered. Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia. Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.; Other Names: Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File; Combination product: BIS 60; Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively. Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room. Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered. Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia. Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.; Other Names: Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
To test the presence of implicit memory under two different planes of surgical general anesthesia in patients undergoing urologic (transurethral) or orthopedic (internal and external fixation) procedures	3 years

Secondary Outcome Measures

Outcome Measure	Time Frame
To compare the pre and postoperative anxiety levels as a marker of clinical significance of operational implicit memory function.	3

Collaborators and Investigators

• Sponsor: University of Oklahoma
• Investigators: Principal Investigator: Mehmet S. Ozcan, MD, University of Oklahoma

Study record dates

Study Major Dates

• Study Start: March 1, 2006
• Primary Completion (Actual): January 1, 2012
• Study Completion (Actual): January 1, 2012

Study Registration Dates

• First Submitted: December 20, 2007
• First Submitted That Met QC Criteria: December 31, 2007
• First Posted (Estimate): January 2, 2008

Study Record Updates

• Last Update Posted (Actual): December 20, 2017
• Last Update Submitted That Met QC Criteria: December 18, 2017
• Last Verified: December 1, 2017

More Information

Terms related to this study

• Keywords: general anesthesia; elective surgery; implicit memory
• Other Study ID Numbers: IRB No: 12634

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO