Awareness During Blended Anaesthesia

Intraoperative Awareness Clinical Trial

Official title:

Relationships Between Bispectral Index (BIS), Implicit Memory Dream Recall and MAC in Blended Anaesthesia

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01800578
• Other study ID #: A1044/2001
• Status: Completed
• Phase: N/A
• First received: November 12, 2012
• Last updated: February 25, 2013
• Start date: September 2005
• Est. completion date: February 2009

Study information

• Verified date: February 2013
• Source: Catholic University of the Sacred Heart
• Contact: n/a
• Is FDA regulated: No
• Health authority: Italy: Ethics Committee
• Study type: Observational

Clinical Trial Summary

the aim of this study was to estimate the relations between Bispectral Index values and explicit or implicit memory or dreams during two different minimal alveolar concentration (MAC) of sevoflurane in patients undergoing blended anaesthesia for major abdominal surgery and ,in this way, estimate the possibility to reduce, in presence of a deep analgesia, like epidural analgesia, the requirement of halogenated volatile anesthetics.

Description:

The decreased responsiveness to stimulation defines depth of anaesthesia which is a balance between effects of anaesthetic drugs and surgical stimulations.

Awareness is a rare occurrence with an incidence of 0,1-0,2 % , defined as postoperative recall of events occurring during general anaesthesia.

Different stages of awareness should be defined: conscious awareness with explicit recalls with pain; conscious awareness with explicit recalls without pain; conscious awareness without explicit recall and possible implicit recall; subconscious awareness without explicit recall and possible implicit recall; no awareness .

This memory can be traumatic and may result in developing a chronic posttraumatic stress disorder (PTSD) in more than half of subjects .

Some cases of awareness are caused by inadequate anesthesia and are potentially avoidable through the assessment of depth of hypnosis by an intraoperative monitoring , especially when muscle relaxants are used.

The Bispectral Index ( BIS ), one of the devices designed to monitor brain activity, through a proprietary algorithm , elaborates EEG and provides an index of hypnotic level.

Thus, several variables, derived from EEG time and frequency domain, are combined into a single index indicating the patient's level of consciousness.

A range between 40 and 60, during surgery, permits both to prevent awareness and to reduce the dose of anesthetic agent administered .

In this study, during major abdominal surgery, an epidural analgesia was performed to suppress afferent noxious stimuli and combined with a general anaesthesia based on halogenates.

Thereby the aim of this study was to estimate the relations between Bispectral Index values and explicit or implicit memory or dreams during two different minimal alveolar concentration (MAC) of sevoflurane in patients undergoing blended anaesthesia for major abdominal surgery and ,in this way, estimate the possibility to reduce, in presence of a deep analgesia, like epidural analgesia, the requirement of halogenated volatile anesthetics.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 36
• Est. completion date: February 2009
• Est. primary completion date: February 2009
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 70 Years

Eligibility

Inclusion Criteria:

native Italian speakers American society of anaesthesiologist physical status I-II -

Exclusion Criteria:refusal of placement of epidural catheter neurological or psychiatric diseases hearing impairment use of drugs know to affect central nervous system coagulopathy heart conditions infections allergy to local anaesthetics liver or renal disease

Study Design

Observational Model: Case-Only, Time Perspective: Prospective

Related Conditions & MeSH terms

• Consciousness Disorders
• Consciousness, Level Depressed
• Intraoperative Awareness

Intervention

Device:
• monitor for depth of hypnosis
evaluation of depth of hypnosis

Locations

Country	Name	City	State
Italy	Catholic University of Sacred Heart	Rome	Rm

Sponsors (1)

Lead Sponsor	Collaborator
Germano De Cosmo

Country where clinical trial is conducted

Italy, 

References & Publications (8)

Aceto P, Valente A, Gorgoglione M, Adducci E, De Cosmo G. Relationship between awareness and middle latency auditory evoked responses during surgical anaesthesia. Br J Anaesth. 2003 May;90(5):630-5. — View Citation

Baars BJ. The brain basis of a "consciousness monitor": scientific and medical significance. Conscious Cogn. 2001 Jun;10(2):159-64; discussion 246-58. — View Citation

Ekman A, Lindholm ML, Lennmarken C, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand. 2004 Jan;48(1):20-6. — View Citation

Ghoneim MM. Incidence of and risk factors for awareness during anaesthesia. Best Pract Res Clin Anaesthesiol. 2007 Sep;21(3):327-43. — View Citation

Osterman JE, Hopper J, Heran WJ, Keane TM, van der Kolk BA. Awareness under anesthesia and the development of posttraumatic stress disorder. Gen Hosp Psychiatry. 2001 Jul-Aug;23(4):198-204. — View Citation

Sandin RH, Enlund G, Samuelsson P, Lennmarken C. Awareness during anaesthesia: a prospective case study. Lancet. 2000 Feb 26;355(9205):707-11. — View Citation

Schwender D, Klasing S, Daunderer M, Madler C, Pöppel E, Peter K. [Awareness during general anesthesia. Definition, incidence, clinical relevance, causes, avoidance and medicolegal aspects]. Anaesthesist. 1995 Nov;44(11):743-54. Review. German. — View Citation

Wong CS. What's the matter of depth of anesthesia? Acta Anaesthesiol Sin. 2001 Mar;39(1):1-2. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	correlation between BIS and free association test score		every 15 min during anaesthesia and 24 h after emergency from anaesthesia	Yes
Secondary	MAC of sevoflurane necessary to avoid awareness		24 h after emergency from anaesthesia	Yes