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Handbook of anæsthetics

Chapter 161: Other Blood changes in Anæsthesia.
By J. Stuart Ross
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About This Book

The handbook provides a concise practical guide to anaesthetic practice, beginning with physiological effects, shock, and asphyxia, then outlining methods of anaesthesia, patient preparation and clinical observation. Subsequent chapters review inhalational agents (nitrous oxide, ether, chloroform, ethyl chloride), gas mixtures and intratracheal techniques, inhaler and apparatus design, sequences of agents, and accident prevention and management. It addresses postoperative sequelae, patient positioning and criteria for choosing agents, and concludes with chapters on local and spinal anaesthesia. Emphasis is placed on safe administration, physiological monitoring, and practical details of equipment and technique.

APPENDIX III.
THE ACTION OF ANÆSTHETICS UPON THE BLOOD.

The Blood Gases in Anæsthesia.

Buckmaster and Gardner (Journal of Physiology, vol. xli., p. 246), analysed the blood gases in various stages of chloroform anæsthesia, and some of their results are shown below in tabular form. They show a very definite reduction in the oxygen content of the blood. So far as one gathers from the text of the paper, the animals were not subjected to any considerable trauma during the progress of the anæsthesia, so that the figures arrived at with regard to the CO2 content do not bear upon the Acapnia question. If there was no trauma, there would be no deep breathing, and a reduction of CO2 could not be expected.

Average volume in
c.c. per 100 c.c.
of blood		 Average composition
per cent. of gas		 Relation
of
O2 to CO2
CO2 O2 Nitr. CO2 O2 Nitr.
Normal cats. 25·07 13·60 1·00 63·2  34·28 2·52 1 to 1·84
Reflexes just re-appearing 29·02 11·49 1·33 65·06 25·44 2·87 1 to 2·55
Reflexes just disappearing 29·57 7·78 2·15 69·14 18·17 5·09 1 to 3·8 
2nd Stage Anæsthesia 36·00 8·14 1·49 71·27 16·12 2·95 1 to 4·32

Other Blood changes in Anæsthesia.

Hamburger and Ewing (Journal of the American Medical Assoc. 1908) examined the blood changes incidental to surgical anæsthesia. Their results may be condensed as follows:—

Nitrous Oxide.—Hæmoglobin is not permanently decreased and no anæmia follows the administration. Hæmolysis is not increased. The coagulation time of the blood is not always affected in the same direction. Usually it is slightly increased.

Ether.—The hæmoglobin is slightly reduced and anæmia persists for seven to ten days. Hæmolysis is not however materially increased. There is some evidence of blood inspissation. The coagulation time is markedly increased.

Chloroform.—The hæmoglobin is reduced and a distinct anæmia produced. Hæmolysis is definitely increased. There is a slight increase in the coagulation time.