Arteriovenous oximeter for O2 content difference, O2 saturations, and hemoglobin content

We combined two spectrophotometric oximeters to measure continuously and simultaneously arteriovenous O2 content difference (AVOD) as well as arterial and venous oxyhemoglobin saturations (SaO2, SvO2) and total hemoglobin concentration (Hb). AVOD of the flowing arterial and venous whole blood was determined by the method of Guyton et al. (J. Appl. Physiol. 10: 158-163, 1957) and Shepherd and Burgar [Am. J. Physiol. 232 (Heart Circ. Physiol. 1): H437-H440, 1977]. The new arteriovenous oximeter was tested in dog experiments in which SaO2, SvO2, Hb, and AVOD were variously changed by temporary suffocation, electric muscle stimulation, hemorrhage and transfusion, and hemodilution with saline. AVOD, SaO2, SvO2, and Hb were compared with the data of the arterial and venous blood sampled near the oximeter cuvettes and measured with an IL282 CO oximeter. In one dog experiment and one in vitro blood experiment, AVOD data of the same arterial and venous blood were compared by connecting the present oximeter in series with an A-VOX Systems oximeter developed by Shepherd and Burgar. The results showed that the new arteriovenous oximeter can continuously measure AVOD, SaO2, SvO2, and Hb over wide ranges with reasonable accuracy.