Gases administered in artifical respiration : with particular reference to the use of carbon dioxide a report to the Medical Research Council ... / written by K.W. Donald and W.D.M. Paton.

  • Donald, K. W. (Kenneth William)
Date:
[1955?]
Catalogue details

Licence: In copyright

Credit: Gases administered in artifical respiration : with particular reference to the use of carbon dioxide a report to the Medical Research Council ... / written by K.W. Donald and W.D.M. Paton. Source: Wellcome Collection.

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    Effects of High Levels of Carbon Dioxide Anaesthetic and Narcotic Effects Carbon dioxide was, in fact, the first gaseous anaesthetic used surgically, and Hickman performed surgical operations on animals under its influence as long ago as 1824 (see Ouncum, 1947). Paul Bert (1878) subsequently confirmed that high concentrations of carbon dioxide (15% upwards) rendered normal animals unconscious, and again suggested its use as an anaesthetic during surgical procedures. Since that time many workers have described the depressant narcotic effect and the antagonism to analeptics produced by high concentrations of carbon dioxide in animals (Gellhorn and Heymans, 1948 ; Stein et al., 1949 ; Pollock, 1949) ; and in man (Richardson, 1885 ; Brown, 1930; Seevers, 1944; Dripps and Comroe, 1947). Stein et al. (1949) reported that 30% carbon dioxide for 30 minutes would prevent electri¬ cally induced convulsions in man. This implies, incident¬ ally, that the administration of carbon dioxide is likely to weaken the effectiveness of any analeptics given during resuscitation. These reports concern the inhalations of high percentages of carbon dioxide by normal subjects, in whom even a normal response to carbon dioxide was unable to prevent severe gaseous acidosis with its attendant dangers. Over 40 years ago Krogh and Lindhard (1913) noted that the administration of oxygen with carbon dioxide appeared to reduce the ventilatory response to the latter gas. Work during the recent war (Barlow et al., 1945; Donald, 1945) showed that in the absence of efficient carbon dioxide absorp¬ tion in respiratory apparatus, exercising subjects breathing oxygen could readily become anaesthetized by carbon dioxide without appreciating any preliminary respiratory stimulation, and that, in resting subjects, concentrations of 10% or more carbon dioxide in oxygen readily induce un¬ consciousness. In controlled respiration, with high oxygen tensions, as used in modem anaesthesia, it has been shown that a rela¬ tively small decrease of minute-volume will cause the body PCO2 to rise to narcotic levels (Orton, 1952 ; Dripps, 1952), and levels of up to 20% carbon dioxide have been recorded (Dripps, 1947 ; Buckley et al., 1953); this may cause con¬ siderable delay in return of consciousness (cf. Scurr, 1954 ; Gray and Fenton, 1954). All anaesthetics and narcotics will, if given in larger doses, finally cause medullary failure, and there is no reason to believe that carbon dioxide is an exception. It has only recently been appreciated that carbon dioxide narcosis, far from being an academic curiosity, is not un¬ common in routine clinical practice (Barach, 1948 ; Donald, 1949 ; Comroe et al., 1950). If patients with very severelv damaged lungs (emphysema, extensive tuberculosis, bronchi¬ ectasis) develop bronchopneumonia, severe bronchitis, or