Ketamine Clinical Trials
Correlation between alcohol concentration and an electroencephalogram (EEG) measure of anaesthetic depth
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Organisation Name: University of Auckland
Overal Status: Completed
Start Date: 25/07/2013
Brief Summary: Bispectral Index monitoring is commonly used intraoperatively to decrease the risk of awareness. Multiple drugs are known to affect the bispectral index and many have been studied in detail. Our aim is to determine the relationship between alcohol concentration and BIS.Countries
Awareness is an uncommon but potentially stressful complication of anaesthesia occurring in 0.1-0.2% of surgical patients. The BIS monitor processes EEG activity with time-domain, frequency domain, and bispectral analysis producing a dimensionless number between 0 and 100 with 40-60 being appropriate for surgery. Large trials have shown a decrease in the occurrence of awareness when using BIS in high-risk patients.[1, 3]
Studies have demonstrated that BIS decreases in patients with head injuries [4, 5], those with cognitive impairment such as dementia  and with sedation . There has been a single case report detailing a case of intracranial arterial alcohol embolization in which the BIS decreased to zero. We hypothesise that BIS will decrease with alcohol consumption.
The effect of multiple drugs such as nitrous oxide, ketamine and opioid on bispectral index has been studied in detail. Alcohol, a commonly consumed drug has not. Miner et al published a paper using BIS to validate the use of Altered Mental Status Scale in intoxicated patients. This study did not aim to determine a relationship between alcohol concentration and BIS and included patients who may have consumed other drugs. Thus, there were potentially many confounding factors that may have influenced the relationship between alcohol concentration and BIS.
1. Myles, P.S., et al., Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet, 2004. 363(9423): p. 1757-63.
2. Dahaba, A.A., Different conditions that could result in the bispectral index indicating an incorrect hypnotic state. Anesth Analg, 2005. 101(3): p. 765-73.
3. Ekman, A., et al., Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand, 2004. 48(1): p. 20-6.
4. Haug, E., et al., Bispectral electroencephalographic analysis of head-injured patients in the emergency department. Acad Emerg Med, 2004. 11(4): p. 349-52.
5. Ebtehaj, M., et al., Correlation between BIS and GCS in patients suffering from head injury. Ir J Med Sci, 2012. 181(1): p. 77-80.
6. Erdogan, M.A., et al., The effects of cognitive impairment on anaesthetic requirement in the elderly. Eur J Anaesthesiol, 2012. 29(7): p. 326-31.
7. Liu, J., H. Singh, and P.F. White, Electroencephalographic bispectral index correlates with intraoperative recall and depth of propofol-induced sedation. Anesth Analg, 1997. 84(1): p. 185-9.
8. Unnikrishnan, K.P., et al., Case report: alterations in bispectral index following absolute alcohol embolization in a patient with intracranial arteriovenous malformation. Can J Anaesth, 2007. 54(11): p. 908-11.
9. Miner, J.R., A. Gaetz, and M.H. Biros, The association of a decreased level of awareness and blood alcohol concentration with both agitation and sedation in intoxicated patients in the ED. Am J Emerg Med, 2007. 25(7): p. 743-8.
- New Zealand
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