A method for the determination of carbon monoxide in blood.

Methods for the determination of carbon monoxide in blood based on spectroscopic analysis (Hartridge, 1922; Klendshoj, Feldstein, and Sprague, 1950) are accurate only when relatively high concentrations of carbon monoxide are present. The two most accurate methods in current use are the manometric method of Van Slyke and Salvesen (1919) and the volumetric method of Scholander and Roughton (1943). Considerable skill and practice are, however, needed to obtain accurate results. These methods have certain disadvantages in that the carbon monoxide is determined after absorption of other blood gases, and corrections have to be made for dissolved nitrogen. The purpose of this paper is to describe a method for the determination of carbon monoxide in blood which is both simple and accurate. The procedure is similar to that used for the determination of nitrous oxide in blood described by Lawther and Bates (1953). The blood gases are extracted under vacuum after reduction of the haemoglobin by acid ferricyanide and are analysed by infra-red absorption. Other blood gases do not interfere with the estimation.