ADVANCE: Assessment for Defining Variability in Anesthesia Through Novel Clinical EEG

Pain Clinical Trial

— CVI  

Official title:

"Advance": Assessment for Defining Variability in Anesthesia

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00689130
• Other study ID #: 251
• Status: Completed
• Phase: N/A
• First received: May 30, 2008
• Last updated: March 6, 2012
• Start date: May 2008
• Est. completion date: October 2008

Study information

• Verified date: November 2008
• Source: Medtronic - MITG
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Observational

Clinical Trial Summary

The present study is designed to compare prospectively whether sBIS, sEMG, or CVI variability (brain monitoring) can be used to predict unwanted intraoperative responses (high blood pressure, fast heart rate, tearing, etc.) to stimulation (pain) and to determine whether these intraoperative findings are related to patient-assessed postoperative pain scores.

The hypothesis is that increases in these variability measures are associated with increased probability of unwanted responses. If confirmed, these variability measures may help anesthesia providers by highlighting periods of inadequate analgesia (pain relief).

Description:

Anesthesia providers have been using processed EEG parameters (brain monitors) to assess the depth of anesthesia for many years. The Bispectral Index (BIS®; Aspect Medical Systems, Inc.), one such brain monitor, provides a direct measure of the hypnotic state of the patient [1, 2]. These clinicians use the BIS value, a number ranging from 0 (very deep anesthesia) to 100 (awake state), to help optimize anesthetic dosing. Using BIS technology, anesthesia providers may adjust anesthesia doses to provide adequate sedation while avoiding over sedation, resulting in faster recovery [3] and a reduced incidence of awareness with recall [4].

While BIS technology helps anesthesia providers achieve desired levels of hypnosis, they currently rely primarily on monitoring hemodynamic (blood pressure and heart rate), autonomic (tearing, sweating), and somatic (moving) responses to noxious (painful) stimulation as a means to detect potential patient arousals. Additional analgesics (narcotics, NSAIDS) are often administered in order to suppress further response to noxious (painful) stimulation. Several studies have shown that noxious stimulation can also affect EEG signals, resulting in increased variability in the BIS index, suggesting that information in EEG signals could potentially help clinicians anticipate and detect patient response to noxious stimulation.

Ropcke et al. [5] showed that BIS values were higher with surgical stimulation than without any stimulation. Other reports have shown that focal noxious stimuli in volunteers and patients induce transient increases in BIS [6-9]. Many of these studies show that adding analgesics suppresses the BIS response to noxious stimulation, and the level of suppression achieved was related to the dose of the added drugs [6, 8, 9].

Based on these findings, it is expected that insufficient analgesia would likely result in transient increases in BIS due to ongoing surgical stimulation, increasing the overall variability of BIS. Recently reported findings confirm that overall variability of BIS increased prior to and following intraoperative somatic events [10]. These reports also identified similar increases in variability of the EMG, with the largest changes realized from a Composite Variability Index (CVI) which combined the BIS variability (sBIS) and EMG variability (sEMG) into a single value. Other studies have also shown an association between these variability measures and postoperative pain scores [11, 12]. These studies showed that sBIS, sEMG, and CVI computed over the entire surgical procedure were all higher in both adults and children with worse postoperative pain scores. However, the reliability and optimum method of displaying these variability scores has yet to be been determined.

The present study is designed to compare whether sBIS, sEMG, or CVI can be used to predict unwanted intraoperative somatic responses to stimulation, and to determine whether these values are related to patient-assessed postoperative pain scores. Our hypothesis is that increases in these variability measures are associated with increased probability of somatic responses. If our hypothesis is confirmed, these variability measures may help clinicians by highlighting periods of inadequate analgesia.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 120
• Est. completion date: October 2008
• Est. primary completion date: October 2008
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 80 Years

Eligibility

Inclusion Criteria:

1. Age range 18-80 years old

2. ASA I through III

3. Scheduled for elective, non-cardiac surgery under General Anesthesia

4. Ability to understand and perform all recovery assessments and procedures

Exclusion Criteria:

1. Subjects with known neurological disorders, including current use of anticonvulsant medications.

2. Subjects with uncontrolled hypertension or other serious medical conditions which would interfere with cardiovascular responses analysis. Subjects on anti-arrhythmics, beta-blockers, or other agents which may reduce the cardiovascular responsiveness to pain and surgical stress.

3. Patients with any contraindications to the selected anesthetic agents specified for each site.

4. Alcohol or illicit drug use which prevents normal functioning in society or has lead to organ toxicity. Chronic use of opioids, narcotics or analgesics which may limit a subject's responsiveness to analgesic dosages.

5. Significant hypotension (systolic BP < 100) or bradycardia (HR < 55) during baseline assessment.

6. Anticipated or planned regional block or extensive local anesthetic for post-operative pain control.

Study Design

Observational Model: Cohort, Time Perspective: Prospective

Related Conditions & MeSH terms

• Pain

Locations

Country	Name	City	State
Spain	Hospital Sanitas La Moraleja Sanchinarro	Madrid
United States	Emory University School of Medicine	Atlanta	Georgia
United States	University of Louisville	Louisville	Kentucky
United States	Saint Vincent Catholic Medical Center	New York	New York

Sponsors (1)

Lead Sponsor	Collaborator
Medtronic - MITG

Countries where clinical trial is conducted

United States,  Spain,