[Study of cerebral blood flow by the modified method of Kety-Schmidt using the original tube for determination of...

For simplifying the method of Kety-Schmidt used in measurements of cerebral blood flow a probe designed specially for this purpose was used for measuring the blood levels of nitrous oxide. The principles of the original method of Kety-Schmidt and the later proposed correction in calculations are described. The device for nitrous oxide determination called N2O-meter consists of a part for measurements and indication, to which cadmium-gold probes are attached fixed to the chambers used for blood investigations. The principle of the probe is based on demonstration of potential differences developing during N2O reduction on the cadmium electrode. Reduction of the volume of blood samples and the use of low concentration of nitrous oxide in the breathing mixture makes this method of cerebral blood flow determination safe for the patient and quick reading of the values increases the usefulness of the method under clinical conditions.