comparing gases

"The solubility of carbon dioxide in blood is greater than that of air, in which nitrogen is the important relatively insoluble component. The serious effects that follow air trapped in the arterial system should be diminished by replacing

this air with an equal quantity of carbon dioxide." (W. SHANG NG AND MICHAEL ROSEN. Thorax)

Animal studies support this argument. In dogs, five times the volume of carbon dioxide as compared with air injected into the left ventricle was necessary to produce the same mortality rate (Kunkler and King, 1959).

"Similarly in cats, Moore and Braselton (1940) found that the fatal dose of carbon dioxide injected into the pulmonary vein was 12 times that of air. Flooding the chest cavity with either carbon dioxide or air in dogs, with the left auricle wide open, gave an incidence

of gross cardiovascular upset three times greater in those dogs that had air in the chest than in the carbon dioxide group. Furthermore, the injection of more than 05 ml./kg. of air into a common carotid artery in dogs always caused severe neurological damage (demonstrated at necropsy), whereas 4 to 8 ml./kg. of carbon dioxide produced transient signs in only 33 % of the dogs, all of which subsequently recovered completely (Eguchi et al., 1963)."  (W. SHANG NG AND MICHAEL ROSEN. Thorax) 

“Carbon dioxide is 20 times more soluble than oxygen; it obeys Henry’s law, which states that the number of molecules in solution is proportional to the partial pressure at the liquid surface" GJ Arthurs M Sudhakar