CJA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text (PDF)
Right arrow Submit a scholarly reply
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by JENKINS, L. C.
Right arrow Articles by PENROSE, G. S.
Right arrow Search for Related Content
PubMed
Right arrow Articles by JENKINS, L. C.
Right arrow Articles by PENROSE, G. S.

Canadian Journal of Anesthesia, Vol 10, 634-647, Copyright © 1963 by Canadian Anesthesiologists' Society

Experimental Central Nervous System Studies Related to Anaesthesia: Clinical Implications. I. Anaesthesia and the Brain Stem Reticular Formation. II. Effect of Reduced Sensory Inflow on Anaesthetic Requirements

LEONARD C. JENKINS B.A., M.D., C.M., F.R.C.P.(C.)1, GEORGE M. LING M.A., PH.D.1, JAMES G. FOULKS M.D., PH.D.1, and G. S. PENROSE M.D., C.M.1

1 Departments of Pharmacology and Anaesthesiology, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia

The reticular formation is an extensive central core of grey matter, which interrelates with the principal afferent and efferent pathways through synaptic connections in the medulla oblongata, pons, and tegmentum of mid-brain. Some aspects of the anatomy and physiology of this subcortical area have been described.

Thiopentone administered intravenously elicits E.E.G. "deactivation" and surgical anaesthesia. The same effects are induced when thiopentone is applied directly in minute quantities into subcortical sites (brain stem reticular formation, preoptic region) of intact freely moving cats, with in-dwelling "cannulae-electrodes."

Preliminary studies have indicated that reduced sensory inflow (e.g. as observed with quadriplegia and high spinal analgesia) plays a significant role in decreasing the concentrations of pharmacological agents required for sedation and clinical anaesthesia. In intact animals, chlorpromazine and thiopentone induce anaesthesia (as reflected in the E.E.G. responses to audiogenic and painful stimulations and in the duration of recovery time) only with doses of the order of magnitude of 10 mg./kg. and 35 mg./kg. respectively. In the Spinal preparation similar anaesthetic effects are achieved with lower concentrations of each compound, and even lower concentrations (chlorpromazine 1.5 mg/kg. and thiopentone 4.0 mg./kg.) suffice in preparations in which both spinal section and cervical dorsalectomy have been performed.

These-observations also emphasize the potential hazard of overdosage with central nervous system depressants in patients with decreased sensory inflow.

Further studies of the effects of various anaesthetic agents on the electrical activity of cortical and subcortical sites are currently being conducted.

Man's neurophysiological uniqueness is entrusted to us during anaesthesia. We, as anaesthetists, must preserve it well, by our judicious use and management of central nervous system depressant drugs—for, indeed, "What a piece of work is a man!".

Note:

This paper was presented in part at the Annual Meeting of the Royal College of Physicians and Surgeons of Canada, Edmonton, Alberta, January, 1963.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1963 by the Canadian Anesthesiologists' Society.