Canadian Journal of Anesthesia, Vol 11, 394-416, Copyright © 1964 by Canadian Anesthesiologists' Society

Comparison of Cardiovascular, Respiratory, and Metabolic Effects of Halothane-Ether Azeotropic Mixture with those of Methoxyflurane Anaesthesia in Man

¹ Department of Anaesthesia and Reanimation, Hôtel-Dieu de Québec, Québec, P Q

The administration of halothane-ether azeotropic mixture to the surgical patients included in this study produced no respiratory depression, no acid-base disturbances, a clear-cut hyperglycaemia, bradycardia, a definite reduction in peripheral resistance, and and elevated cardiac output The above observations suggest an absence of significant myocardial depression with the azeotrope when used m normal clinical concentrations A sustained increase in myocardial efficiency is produced, which might be beneficial in terms of visceral perfusion In our opinion, cardiac sympathetic nerves and beta receptors are not blocked by the halothane fraction, their activation by the ether fraction being a major tactor of safety for the heart Mutual corrective effects of these two fractions result in a sound, balanced anaesthetic state

So far halothane-ether and methoxyflurane have been shown to differ in many respects In the future, it will be possible to stress with more precision the indications for each For the time being, what we appreciate most in methoxyflurane is its wide margin of safety and the remarkable stability it gives to haemodynamics during maintenance What we appreciate most in the azeotiope is its flexibility (at the price, it is true, of a somewhat narrower margin of safety) and the preservation of a warm, pink, and dry patient who, to the satisfaction of all concerned, will fall asleep quickly and will rapidly awaken from sleep

Note:

Presented at the Annual Meeting Canadian Anaesthetists Society, May 10–14, 1964