None listed
Conditions
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. Awareness is an uncommon but potentially stressful complication of anaesthesia occurring in 0.1-0.2% of surgical patients.[1] 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.[2] 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 [6] and with sedation [7]. There has been a single case report detailing a case of intracranial arterial alcohol embolization in which the BIS decreased to zero[8]. 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.[2] 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.[9] 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.
Interventions
Participants will attend just one study day (for one four hour session). They will be asked to refrain from consuming caffeine from 10am on the study day. Only participants who are not rostered for clinical duties over the ensuing 24 hours will be able to participate in the study. Alcohol will be provided for study participants to consume over 3 hours. They will be asked to drink a similar amount of alcohol to that which they would normally drink at home or when out. The type and amount of alcoh
Participants will attend just one study day (for one four hour session). They will be asked to refrain from consuming caffeine from 10am on the study day. Only participants who are not rostered for clinical duties over the ensuing 24 hours will be able to participate in the study. Alcohol will be provided for study participants to consume over 3 hours. They will be asked to drink a similar amount of alcohol to that which they would normally drink at home or when out. The type and amount of alcohol consumed throughout the study will be recorded. Wine, beer, nonalcoholic drinks and snacks will be provided during the study period, and a meal will be provided at the end of the study. Four measurments of breath alcohol, and of BIS, will be taken for each participant (hourly, over the four hour study period) plus one set of baseline measurements. A single blood sample will be taken at the end of the study to confirm blood alcohol levels.
Sponsors
University of Auckland
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
25 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Anaesthetic Trainees (age between 25 and 40 years) who have completed their clinical duties on a Friday afternoon and are not rostered to work for at least 24 hours.
Exclusion criteria
History of epilepsy; currently taking any sedating medication including analgesics such as codeine and opioids, benzodiazepines, anti-epileptics and sleeping medications; history of liver disease or impaired liver function; currently pregnant.
Outcome results
None listed