<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

*Baoguo Wang, M.D.,# Qin Bai, M.D., &Xiping Jiao, M.D., &Enzhen Wang, M.D.,** Paul F. White, Ph.D., M.D.

*Department of Anesthesiology, Beijing Tiantan Hospital, Capital University of Medical Sciences,

#Department of Neurophysiology, Beijing Neurosurgical Institute, The People’s Republic of China.

**Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas. Dallas.Texas.U.S.A

Address all correspondence and reprint requests to:Dr. Paul F. White

Professor and McDermott Chair of Anesthesiology

Department of Anesthesiology and Pain Management

University of Texas Southwestern Medical Center.

5323 Harry Hines Blvd,

Dallas, Texas 75235-9068

Phone: (214) 648-6424

Fax: (214) 648-7660

E-mail:　pwhite@mednet.swmed.edu

Abbreviated title：Effect of propofol on EEG activity in epileptic vs non-epileptic neurosurgical patients<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Summary：Propofol is alleged to possess both pro- and anticonvulsant properties, leading to controversy regarding its use in patients with a history of seizures. Since propofol is administered for both sedation and hypnosis, it is important to understand the effects of low (0.5-1.0 mg/kg) and high (2-2.5 mg/kg) doses of propofol on the electroencephalogram (EEG). In this study, the hemodynamic and EEG effects of cumulative doses of propofol from 0.5 to 2.5 mg/kg i.v. were studied in 30 neurosurgical patients with or without a history of seizure disorders. While continuously recording from scalp EEG electrodes (F₃, F₄, C₃, C₄, P₃, P₄, O₁ and O₂), propofol 0.5 mg/kg  was infused intravenously over 20 s. The same dose of propofol was reinjected four times at 2-min interval, until a total dose of 2.5 mg/kg had been administered. The number and average amplitude of the EEG waves were counted and measured manually, respectively, from 80 to 90 s after beginning the injection of each  dose of propofol. After lower propofol doses (0.5-1 mg/kg), the number of β-waves increased .while α- and θ-waves decreased significantly in all patients. However, with larger doses of propofol (total dose of 2-2.5 mg/kg), the number of β-waves decreased and δ-waves appeared. The amplitude of all EEG waves increased and were maintained at a higher level after administration of propofol. Spike (or sharp) waves appeared in 33% of the control patients and in 40% of the epileptic group after propofol 0.5 mg/kg and in 73% of the control and 67% of the epileptic patients after the 1.5 mg/kg dose. In the majority of patients, the spike waves disappeared when additional doses of propofol were administered. One patient in the epileptic group had an EEG-recorded and clinical grand mal seizure after propofol 1 mg/kg, but the seizure disappeared after an additional 0.5 mg/kg bolus dose was administered. The propofol-induced EEG changes appeared initially at the frontal and central EEG electrodes, and subsequently at the other EEG electrodes and subsequently at the other EEG elctrodes. Overall, there were no significant differences in the spectrum of EEG changes between the two patient populations. It is concluded that  propofol produces similar dose-dependent effects on EEG activity in patients with or without a history of seizure disorders. While induction of anesthesia with higher doses of propofol (> 1.5 mg/kg) in neurosurgical patients with well-controlled seizure disorder is safe, smaller sedative doses should be administered with caution to epileptic patients.

Key words: Propofol-Seizure-Electroencephalogram (EEG).

12. Simpson KH, Halsall PJ, Carr CM, et al: Propofol reduces seizure duration in patients having anaesthesia for electroconvulsive therapy. Br J Anaesth 1988; 61:343-4.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

13. Lowson S, Gent JP, Goodchild CS: Anticonvulsant properties of propofol and thiopentone: comparison using two tests in laboratory mice. Br J Anaesth 1990; 64:59-63.

14. Modica PA, Tempelhoff R, White PF: Pro- and anticonvulsant effects of anesthetics (Part I). Anesth Analg 1990; 70:303-15.

15. Modica PA, Tempelhoff R, White PF: Pro- and anticonvulsant effects of anesthetics (Part II). Anesth Analg 1990; 70:433-44.

16. Mackenzie SJ, Kapadia F, Grant IS: Propofol infusion for control of status epilepticus. Anaesthesia  1990; 45:1043-5.

17. Wood PR, Browne GPR, Pugh S: Propofol infusion for the treatment of status epilepticus [letter]. Lancet  1988; I:480-1.

18. McBurney JW, Teiken PJ, Moon MR: Propofol for treating status epilepticus. J Epilepsy  1994; 7:21-2.

19. Seifert HA, Blouin RT, Conard PF, et al: Sedative doses of propofol increase beta activity of the processed electroencephalogram. Anesth Analg  1993;76:976-8.

20. Veselis RA, Reinsel RA, Wronski M, et al: EEG and memory effects of low-dose infusions of propofol. Br J Anaeth 1992; 69:246-54.

21. Kearse LA, Fahmy NR. The electroencephalographic effects of propofol anesthesia in human: a comparison with thiopental/enflurane anesthesia. Anesthesiology 1989; 71:A121.

22. Borgeat A, Dessibourg C, Popovic V, et al: Propofol and spontaneous movements: an EEG study. Anesthesiology  1991; 74:24-7.

23. Cottrell JE, Smith DS ed: Anesthesia and neurosurgery. 3rd ed, St. Louis, Mosby-Year Book, Inc., 1994:495-520.

24. Drummond JC, Iragui-Madoz VJ, Alksne JF, et al: Masking of epileptiform activity by propofol during seizure surgery. Anesthesiology  1992; 76:652-4.

25. Samra SK, Sneyd JR, Ross DA, et al: Effects of propofol sedation on seizures and intracranially recorded epileptiform activity in patients with partial epilepsy. Anesthesiology 1995; 82:843-51.

26. Hufnagel A, Elger CE, Nadstawek J, et al: Specific response of the epileptic focus to anesthesia with propofol. J Epileps. 1990; 3:37-45.

27. Ebrahim ZY, Schubert A, Van Ness P, et al: The effect of propofol on the electroencephalogram of patients with epilepsy. Anesth Analg  1994; 78:275-9.

28. Cheng MA, Tempelhoff R, Silbergeld DL, et al: Large-dose propofol alone in adult epileptic patients: electrocorticographic results. Anesth Analg  1996; 83:169-74.