An attempt to find a practical method of carbon dioxide measurement during anaesthesia.

RECENTLY a great deal of attention has been focused on the problem of carbon dioxide accumulation during anaesthesia (Stead et ah, 1953; Harbord, and Lucas, 1953). A number of articles have appeared describing investigations on the actual figures for " alveolar air " or arterial carbon dioxide tensions found during anaesthesia. Ringrose et al. (1950) developed a carbon dioxide indicator showing a qualitative measurement of carbon dioxide in anaesthetic atmospheres. Harrison and Jones (1955) were unable to find, however, that this method has a practical value. Engell and Ibsen (1952) used a carbovisor based on a photoelectrical principle to obtain a continuous recording of carbon dioxide estimations during thoracic operations. Eastwood and Harbord (1955) correlated the changes in tidal volume with those of " alveolar air " concentrations.