Patent ID: 7561256

Claim:
An apparatus for determining the blood oxygen content of a blood sample in connection with a cardiac catheter examination, wherein a catheter is located in a position of interest in the heart, the apparatus being coupled with a cardiac catheter measuring system, said apparatus comprising: a measuring cell for receiving a blood sample which can be transilluminated with a light source, said light source and a means for determining the luminous intensity corresponding to said light source are arranged on said measuring cell for determining the luminous intensity of the light of said light source emerging from said measuring cell, said measuring cell having constant, predefined properties with respect to the light of said light source, whereby the blood oxygen content of the blood sample can be detected due to a change of the luminous intensity of the light of said light source on said means for determining the luminous intensity; a suction device and a tube system for sucking off a sodium chloride solution from said measuring cell, said tube system being coupled with the catheter located in a position of interest in the heart, whereby a blood sample can be received in said measuring cell; a control unit for automatically performing a specified measurement routine during operation, in which said measuring cell is transilluminated with light on a specified length of path, the intensity of the light is measured upon transillumination, the presence of blood in said measuring cell is detected based on the measured intensity of the light, a measurement of the blood oxygen content of the blood sample in said measuring cell by transillumination of said measuring cell is started and performed if the presence of blood has been detected in the previous step, whereby blood oxygen values below 50% blood oxygen saturation can be determined, and sodium chloride solution is introduced into said measuring cell by means of said suction device to remove the blood sample from said measuring cell and to recirculate the blood to the position of interest in the heart from which it was withdrawn.