Clinical trial NCT01800578: Awareness During Blended Anaesthesia
Official title: Relationships Between Bispectral Index (BIS), Implicit Memory Dream Recall and MAC in Blended Anaesthesia
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Consciousness, Level Depressed
Intraoperative Awareness
Keywords: Cerebral State Index Monitor
Lead sponsor: Catholic University of the Sacred Heart
Sponsor class: OTHER
First posted: 2013-02-27
Enrollment: 36
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_ONLY
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: patients undergoing elective major abdominal surgery

Brief 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.

Detailed 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.

Eligibility criteria: 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

-

Primary outcomes:
measure: correlation between BIS and free association test score
timeFrame: every 15 min during anaesthesia and 24 h after emergency from anaesthesia
Secondary outcomes:
measure: MAC of sevoflurane necessary to avoid awareness
timeFrame: 24 h after emergency from anaesthesia
Other outcomes:
Locations:
city: Rome
country: Italy
facility: Catholic University of Sacred Heart
state: Rm
Study officials:
affiliation: Catholic University
name: De Cosmo Germano, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Wong CS. What's the matter of depth of anesthesia? Acta Anaesthesiol Sin. 2001 Mar;39(1):1-2. No abstract available.
citation: Sandin RH, Enlund G, Samuelsson P, Lennmarken C. Awareness during anaesthesia: a prospective case study. Lancet. 2000 Feb 26;355(9205):707-11. doi: 10.1016/S0140-6736(99)11010-9.
citation: Schwender D, Klasing S, Daunderer M, Madler C, Poppel E, Peter K. [Awareness during general anesthesia. Definition, incidence, clinical relevance, causes, avoidance and medicolegal aspects]. Anaesthesist. 1995 Nov;44(11):743-54. doi: 10.1007/s001010050209. German.
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. doi: 10.1016/s0163-8343(01)00142-6.
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. doi: 10.1006/ccog.2001.0510.
citation: Ghoneim MM. Incidence of and risk factors for awareness during anaesthesia. Best Pract Res Clin Anaesthesiol. 2007 Sep;21(3):327-43. doi: 10.1016/j.bpa.2007.05.002.
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. doi: 10.1111/j.1399-6576.2004.00260.x.
citation: 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. doi: 10.1093/bja/aeg113.