[en] We investigated the effects of the general anesthetic agent propofol on cerebral structures involved in the processing of vibrotactile information. Using positron emission tomography (PET) and the H(2)(15)O bolus technique, we measured regional distribution of cerebral blood flow (CBF) in eight healthy human volunteers. They were scanned under five different levels of propofol anesthesia. Using a computer-controlled infusion, the following plasma levels of propofol were targeted: Level W (Waking, 0 microg/ml), Level 1 (0.5 microg/ml), Level 2 (1.5 microg/ml), Level 3 (3.5 microg/ml), and Level R (Recovery). At each level of anesthesia, two 3-min scans were acquired with vibrotactile stimulation of the right forearm either on or off. The level of consciousness was evaluated before each scan by the response of the subject to a verbal command. At Level W, all volunteers were fully awake. They reported being slightly drowsy at Level 1, they had a slurred speech and slow response at Level 2, and they were not responding at all at Level 3. The following variations in regional CBF (rCBF) were observed. During the waking state (Level W), vibrotactile stimulation induced a significant rCBF increase in the left thalamus and in several cortical regions, including the left primary somatosensory cortex and the left and right secondary somatosensory cortex. During anesthesia, propofol reduced in a dose-dependent manner rCBF in the thalamus as well as in a number of visual, parietal, and prefrontal cortical regions. At Level 1 through 3, propofol also suppressed vibration-induced increases in rCBF in the primary and secondary somatosensory cortex, whereas the thalamic rCBF response was abolished only at Level 3, when volunteers lost consciousness. We conclude that propofol interferes with the processing of vibrotactile information first at the level of the cortex before attenuating its transfer through the thalamus.
Disciplines :
Anesthesia & intensive care
Author, co-author :
Bonhomme, Vincent ; Université de Liège > Département des sciences cliniques > Département des sciences cliniques
Fiset, P.
Meuret, P.
Backman, S.
Plourde, G.
Paus, T.
Bushnell, M. C.
Evans, A. C.
Language :
English
Title :
Propofol anesthesia and cerebral blood flow changes elicited by vibrotactile stimulation: a positron emission tomography study.
Publication date :
2001
Journal title :
Journal of Neurophysiology
ISSN :
0022-3077
eISSN :
1522-1598
Publisher :
American Physiological Society, United States - Maryland
Angel A., LeBeau F. (1992) Comparison of the effects of propofol with other anaesthetic agents on the centripetal transmission of sensory information. Gen Pharmacol 23:945-963.
Athwal B.S., Friston K., Frackowiak R.S. (1998) Monotonic temporal effects in PET are regionally specific. Neuroimage 7.
Brust J.C.M. (1991) Cerebral circulation: Stroke. Principles of Neural Science , New York: Elsevier; 1041-1049.
Coghill R.C., Talbot J.D., Evans A.C., Meyer E., Gjedde A., Bushnell M.C., Duncan G.H. (1994) Distributed processing of pain and vibration by the human brain. J Neurosci 14:4095-4108.
Collins D.L., Neelin P., Peters T.M., Evans A.C. (1994) Automatic 3D inter-subject registration of MR volumetric data in standardized Talairach space. J Comput Assist Tomogr 18:192-205.
Dunnet J.M., Prys-Roberts C., Holland D.E., Browne B.L. (1994) Propofol infusion and the suppression of consciousness: Dose requirements to induce loss of consciousness and to suppress response to noxious and non-noxious stimuli. Br J Anaesth 72:29-34.
Enlund M., Andersson J., Hartvig P., Valtysson J., Wiklund L. (1997) Cerebral normoxia in the rhesus monkey during isoflurane- or propofol-induced hypotension and hypocapnia, despite disparate blood-flow patterns: A positron emission tomography study. Acta Anaesth Scand 41:1002-1010.
Hofle N., Paus T., Reutens D., Fiset P., Gotman J., Evans A.C., Jones B. (1997) Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans. J Neurosci 17:4800-4808.
Jezzard P., Rauschecker J.P., Malonek D. (1997) An in vivo model for functional MRI in cat visual cortex. Magn Reson Med 38:699-705.
Maquet P., Degueldre C., Delfiore G., Peters J.M., Luxen A., Franck G. (1997) Functional neuroanatomy of human slow wave sleep. J Neurosci 17:2807-2812.
Newman M.F., Murkin J.M., Roach G., Croughwell N.D., White W.D., Clements F.M., Reves J.G. (1995) Cerebral physiologic effects of burst suppression doses of propofol during nonpulsatile cardiopulmonary bypass. Anesth Analg 81:452-457.
Ohta S., Meyer E., Fujita H., Reutens D., Evans A.C., Gjedde A. (1996) Cerebral [15O]water clearance in humans determined by PET. I. Theory and normal values. J Cereb Blood Flow Metab 16:765-780.
Paus T. Functional anatomy of arousal and attention systems in the human brain. Prog Brain Res, In press; .
Paus T., Zatorre R.J., Hofle N., Caramanos Z., Gotman J., Petrides M., Evans A.C. (1997) Time-related changes in neural systems underlying attention and arousal during the performance of an auditory vigilance task. J Cognit Neurosci 9:392-408.
Plummer G.F. (1987) Improved method for the determination of propofol in blood by high-performance liquid chromatography with fluorescence detection. J Chromatogr 421:171-176.
Raichle M., Martin W., Herscovitch P., Mintun M., Markham J. (1983) Brain blood flow measured with intravenous H215O. II. Implementation and validation. J Nucl Med 24:790-798.
Sokal R.R., Rohlf F.J. Biometry, San Francisco, CA: Freeman; 1981.
Stephan H., Sonntag H., Schenk H.D., Kohlhausen S. (1987) Effect of propofol on the circulation and oxygen consumption of the brain and CO2 reactivity of brain vessels in the human. Anaesthesist 36:60-65.
Strebel S., Lam A.M., Matta B., Mayberg T.S., Aaslid R., Newell D.W. (1995) Dynamic and static cerebral autoregulation during isoflurane, desflurane, and propofol anesthesia. Anesthesiology 83:66-76.
Svensson P., Minoshima S., Beydoun A., Morrow T.J., Casey K.L. (1997) Cerebral processing of acute skin and muscle pain in humans. J Neurophysiol 79:450-460.
Worsley K.J., Evans A.C., Marrett S., Neelin P. (1992) Determining the number of statistically significant areas of activation in subtracted activation studies from PET. J Cereb Blood Flow Metab 12:900-918.