Skip to main navigation menu Skip to main content Skip to site footer

Original article

Vol. 143 No. 1112 (2013)

Effects of dexmedetomidine on performance of bispectral index as an indicator of loss of consciousness during propofol administration

  • Zheng Chen
  • Dong-Hua Shao
  • Li-Hua Hang
Cite this as:
Swiss Med Wkly. 2013;143:w13762


OBJECTIVE: The performance of bispectral index (BIS) for the measurement of the sedative depth when dexmedetomidine is administered in propofol anaesthesia and sedation has not yet been established. This study evaluated the effects of adjunctive dexmedetomidine on the accuracy of BIS to predict loss of consciousness (LOC) and BIS values predicting LOC during propofol administration.

METHODS: In this randomised, double-blind and placebo-controlled trial, 225 patients scheduled for general anaesthesia were assigned to one of three groups. Dexmedetomidine 0.5 and 1.0 µg kg–1 were intravenously infused for 15 minutes in the dexmedetomidine 0.5 and 1.0 µg kg–1groups, and saline was infused in the control group. Propofol was administered as an effect-site target-controlled infusion after completion of dexmedetomidine infusion. Patients in each group were allocated to five subgroups in which the concentration of propofol was set at 0, 1, 2, 3 and 4 μg ml–1, respectively. Three minutes after propofol administration, the BIS values and Observer’s Assessment of Alertness/Sedation (OAA/S) scores were recorded.

RESULTS: There were no significant differences in the prediction probability of BIS for detecting LOC in the three groups. At the time of LOC, BIS50 values were 71.1 and 71.4 in the dexmedetomidine 0.5 and 1.0 µg kg–1groups, respectively, which were significantly larger than the BIS50 of 63.2 in the control group.

CONCLUSIONS: The ability of BIS to predict LOC is not influenced by dexmedetomidine during propofol administration, but BIS values are enhanced at the time of LOC.

This study has been registered with (number NCT00479661)


  1. Khan ZP, Ferguson CN, Jones RM. Alpha-2 and imidazoline receptor agonists. Their pharmacology and therapeutic role. Anaesthesia. 1999;54(2):146–65.
  2. Ebert TJ, Hall JE, Barney JA, Uhrich TD, Colinco MD. The effects of increasing plasma concentrations of dexmedetomidine in humans. Anesthesiology. 2000;93(2):382–94.
  3. Arcangeli A, D’Alò C, Gaspari R. Dexmedetomidine use in general anaesthesia. Curr Drug Targets. 2009;10(8):687–95.
  4. Afonso J, Reis F. Dexmedetomidine: current role in anesthesia and intensive care. Rev Bras Anestesiol. 2012;62(1):118–33.
  5. Ghodki PS, Thombre SK, Sardesai SP, Harnagle KD. Dexmedetomidine as an anesthetic adjuvant in laparoscopic surgery: An observational study using entropy monitoring. J Anaesthesiol Clin Pharmacol. 2012;28(3):334–8.
  6. Ngwenyama NE, Anderson J, Hoernschemeyer DG, Tobias JD. Effects of dexmedetomidine on propofol and remifentanil infusion rates during total intravenous anesthesia for spine surgery in adolescents. Paediatr Anaesth. 2008;18(12):1190–5.
  7. Kunisawa T, Ueno M, Kurosawa A, Nagashima M, Hayashi D, Sasakawa T, et al. Dexmedetomidine can stabilize hemodynamics and spare anesthetics before cardiopulmonary bypass. J Anesth. 2011;25(6):818–26.
  8. Myles PS, Leslie K, McNeil J, Forbes A, Chan MT. Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet. 2004;363(9423):1757–63.
  9. Ekman A, Lindholm ML, Lennmarken C, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand. 2004;48(1):20–6.
  10. Struys MM, Jensen EW, Smith W, Smith NT, Rampil I, Dumortier FJ, et al. Performance of the ARX-derived auditory evoked potential index as an indicator of anesthetic depth: a comparison with bispectral index and hemodynamic measures during propofol administration. Anesthesiology. 2002;96(4):803–16.
  11. Glass PS, Bloom M, Kearse L, Rosow C, Sebel P, Manberg P. Bispectral analysis measures sedation and memory effects of propofol, midazolam, isoflurane, and alfentanil in healthy volunteers. Anesthesiology. 1997;86(4):836–47.
  12. Park KS, Hur EJ, Han KW, Kil HY, Han TH. Bispectral index does not correlate with observer assessment of alertness and sedation scores during 0.5% bupivacaine epidural anesthesia with nitrous oxide sedation. Anesth Analg. 2006;103(2):385–9.
  13. Suzuki M, Edmonds HL Jr, Tsueda K, Malkani AL, Roberts CS. Effect of ketamine on bispectral index and levels of sedation. J Clin Monit Comput. 1998;14(5):373.
  14. Struys MM, Vereecke H, Moerman A, Jensen EW, Verhaeghen D, De Neve N, et al. Ability of the bispectral index, autoregressive modelling with exogenous input-derived auditory evoked potentials, and predicted propofol concentrations to measure patient responsiveness during anesthesia with propofol and remifentanil. Anesthesiology. 2003;99(4):802–12.
  15. Mi WD, Sakai T, Singh H, Kudo T, Kudo M, Matsuki A. Hypnotic endpoints vs. the bispectral index, 95% spectral edge frequency and median frequency during propofol infusion with or without fentanyl. Eur J Anaesthesiol. 1999;16(1):47–52.
  16. Nelson LE, Lu J, Guo T, Saper CB, Franks NP, Maze M. The alpha2-adrenoceptor agonist dexmedetomidine converges on an endogenous sleep-promoting pathway to exert its sedative effects. Anesthesiology. 2003;98(2):428–36.
  17. Huupponen E, Maksimow A, Lapinlampi P, Särkelä M, Saastamoinen A, Snapir A, et al. Electroencephalogram spindle activity during dexmedetomidine sedation and physiological sleep. Acta Anaesthesiol Scand. 2008;52(2):289–94.
  18. Li HL, She SZ, Yan Y, Zhu SM. Effect of dexmedetomidine on bispectral index and auditory evoked potential index during anesthesia with target controlled infusion of propofol and remifentanyl. Zhejiang Da Xue Xue Bao Yi Xue Ban. 2010; 39(1):84–8.
  19. Kasuya Y, Govinda R, Rauch S, Mascha EJ, Sessler DI, Turan A. The correlation between bispectral index and observational sedation scale in volunteers sedated with dexmedetomidine and propofol. Anesth Analg. 2009;109(6):1811–5.
  20. Struys MM, De Smet T, Depoorter B, Versichelen LF, Mortier EP, Dumortier FJ, et al. Comparison of plasma compartment versus two methods for effect compartment-controlled target-controlled infusion for propofol. Anesthesiology. 2000;92(2):399–406.
  21. Smith WD, Dutton RC, Smith NT. Measuring the performance of anesthetic depth indicators. Anesthesiology. 1996;84(1):38–51.
  22. Johansen JW. Update on bispectral index monitoring. Best Pract Res Clin Anaesthesiol. 2006;20(1):81–99.
  23. Dutta S, Karol MD, Cohen T, Jones RM, Mant T. Effect of dexmedetomidine on propofol requirements in healthy subjects. J Pharm Sci. 2001;90(2):172–81.
  24. Peden CJ, Cloote AH, Stratford N, Prys-Roberts C. The effect of intravenous dexmedetomidine premedication on the dose requirement of propofol to induce loss of consciousness in patients receiving alfentanil. Anaesthesia. 2001;56(5):408–13.
  25. Sakai T, Singh H, Mi WD, Kudo T, Matsuki A. The effect of ketamine on clinical endpoints of hypnosis and EEG variables during propofol infusion. Acta Anaesthesiol Scand. 1999;43(2):212–6.
  26. Lysakowski C, Dumont L, Pellegrini M, Clergue F, Tassonyi E. Effects of fentanyl, alfentanil, remifentanil and sufentanil on loss of consciousness and bispectral index during propofol induction of anaesthesia. Br J Anaesth. 2001;86(4):523–7.
  27. Drummond JC. Monitoring depth of anesthesia: with emphasis on the application of the bispectral index and the middle latency auditory evoked response to the prevention of recall. Anesthesiolog. 2000;93(3):876–82.
  28. Lawrence CJ, Prinzen FW, de Lange S. The effect of dexmedetomidine on nutrient organ blood flow. Anesth Analg. 1996;83(6):1160–5.