A direct method for determination of oxygen and carbon dioxide tensions in blood.

Although satisfactory techniques for the determination of oxygen and carbon dioxide contents of blood have long been available, methods for the determination of gas tensions have been less satisfactory and, in the case of the most frequently used procedures, indirect ((1) pp. 174, 298). The direct methods ((1) p. 309; (2-7)) depend upon the equilibration of a bubble of gas with blood at 37” and analysis of the bubble for carbon dioxide and oxygen. In the method to be described the technical problems inherent in the direct approach are minimized by the use of an instrument recently devised by Roughton and Scholander for micro gasometric analyses (8). The Roughton-Scholander (R-S) syringe, consisting of a syringe to which a calibrated capillary tube has been fused, is used both as equilibration chamber and bubble analyzer.