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Selected Publication:
Talakic, E.
Entropy indices versus the bispectral index (BIS) for estimating nociception during combined propofol anesthesia and Femoral Nerve block
[ Dissertation ] Medical University of Graz; 2011. pp. 30
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- Authors Med Uni Graz:
- Talakic Emina
- Advisor:
- Metzler Helfried
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- Abstract:
- Background: Consciousness monitoring has become increasingly popular in general anesthesia, and a new technology has recently been introduced with potential advantages over the other available products. Bispectral index (BIS) and state/response entropy (SE/RE) index have been widely used to estimate depth of anesthesia and sedation. In adults, independent of age, adequate and safe depth of anesthesia for surgery is usually assumed when these indices are between 40 and 60. Since its introduction in 1996, the Bispectral IndexTM (BISTM) has gained increasing popularity as a monitoring tool for the depth of anesthesia. Many reports on the value of BIS have been published in the literature paradoxically changing or inaccurately indicating the depth of anesthesia. Methods: Fifty American Society of Anesthesiologists (ASA) classification I-II patients, aged 18-59 years, undergoing general surgery on the lower limb were recruited in the study. We recruited two groups, one group was maintained at BIS around 25 and the other group of 25 patients was maintained at BIS around 50. Exclusion criteria was body mass index <18 or >26 kg m-2 and subjects with medical conditions that could affect the level of consciousness such as stroke, stupor or dementia, or patients on treatment with cardiovascular or sedative/hypnotic drugs that might affect BIS monitoring. BIS and Entropy electrodes were placed on patients forehead. For monitoring the level of analgesia we use BIS variability (BIS standard deviation) and Entropy bias (response entropy-state entropy). Results: There were no significant differences between the demographic data of the 2 groups. Our results indicate no significant differences with increasing degrees of noxious stimulation starting from 10 mA till 80 mA. And there were no significant differences between two groups as well. Discussion: We demonstrated that neither monitor could successful monitor the depth of analgesia.