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Circulatory shock is lethal, if not promptly diagnosed and effectively treated. Typically, circulatory shock resuscitation is
guided by blood pressure, heart rate, and mental status, which have poor predictive value. In patients, in whom early goaldirected
therapy was applied using central venous oxygenation measurement, a substantial reduction of mortality was reported
(from 46.5% to 30%). However, central venous catheterization is invasive, time-consuming and often results in
complications. We proposed to use the optoacoustic technique for noninvasive, rapid assessment of central venous
oxygenation. In our previous works we demonstrated that the optoacoustic technique can provide measurement of blood
oxygenation in veins and arteries due to high contrast and high resolution. In this work we developed a novel
optoacoustic system for noninvasive, automatic, real-time, and continuous measurement of central venous oxygenation.
We performed pilot clinical tests of the system in human subjects with different oxygenation in the internal jugular vein
and subclavian vein. A novel optoacoustic interface incorporating highly-sensitive optoacoustic probes and standard
ultrasound imaging probes were developed and built for the study. Ultrasound imaging systems Vivid i and hand-held
Vscan (GE Healthcare) as well as Site-Rite 5 (C.R. Bard) were used in the study. We developed a special algorithm for
oxygenation monitoring with minimal influence of overlying tissue. The data demonstrate that the system provides
precise measurement of venous oxygenation continuously and in real time. Both current value of the venous oxygenation
and trend (in absolute values and for specified time intervals) are displayed in the system. The data indicate that: 1) the
optoacoustic system developed by our group is capable of noninvasive measurement of blood oxygenation in specific
veins; 2) clinical ultrasound imaging systems can facilitate optoacoustic probing of specific blood vessels; 3) the
optoacoustic system provides noninvasive monitoring during rapid changes in blood oxygenation.
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