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Depth of Anesthesia on Implicit Memory

University of Oklahoma (OU) logo

University of Oklahoma (OU)

Status

Completed

Conditions

Anesthesia, General
Memory

Treatments

Combination Product: BIS 40
Combination Product: BIS 60

Study type

Interventional

Funder types

Other

Identifiers

NCT00584324
IRB No: 12634

Details and patient eligibility

About

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.

Full 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).

Enrollment

70 patients

Sex

All

Ages

55 to 90 years old

Volunteers

No Healthy Volunteers

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

Trial design

Primary purpose

Supportive Care

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

Double Blind

70 participants in 2 patient groups

Bispectral Index (BIS) 40
Experimental group
Description:
Target BIS 40
Treatment:
Combination Product: BIS 40
Combination Product: BIS 60
Bispectral Index (BIS) 60
Experimental group
Description:
Target BIS 60
Treatment:
Combination Product: BIS 40
Combination Product: BIS 60

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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