Rinat O. Esenaliev, Yuriy Petrov, Irene Y. Petrov, Donald S. Prough
University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1156
Popular version of invited paper
“Novel, noninvasive optoacoustic platform for multiparameter patient monitoring”
Presented Friday morning, May 27, 2011
161st ASA Meeting, Seattle, Wash.
LAY LANGUAGE VERSION
Our group has pioneered a novel, high-resolution, high-contrast diagnostic modality for noninvasive monitoring, imaging, and sensing. This modality is referred to as “optoacoustics” or “photoacoustics” and utilizes sensitive detection of ultrasonic (acoustic) waves induced by harmless near-infrared light pulses (similar to that used in TV remote controls). Because the acoustic waves travel in a straight line from the source, the depth of the target tissue (typically a blood vessel) can be precisely calculated from the time required for the signal to return and the speed of sound through tissue. In contrast, detection of light that has been transmitted through tissue is confounded by extreme scattering. Therefore, the optoacoustic technique yields a noninvasive diagnostic modality with exceptional sensitivity and spatial resolution.
Our objective is to improve patient care by developing and commercializing the noninvasive, optoacoustic diagnostic platform for accurate and continuous monitoring of important physiological parameters including total hemoglobin concentration (hemoglobin content in blood), venous oxygenation (oxygen level) in the brain, central venous oxygenation, cardiac output, circulating blood volume, cardiac index, systemic oxygen delivery, hepatic function. Estimated US market for the optoacoustic diagnostic platform exceeds $2 billion/year.
Currently, invasive measurements of these parameters are routinely used in the care of large populations of patients. Brain and spinal cord injury due to accidents (including car accidents) is a major cause of death for individuals under 50 years of age. It is well established that low cerebral venous oxygenation (below 50%) results in death or severe neurologic complications. However, at present, no technique is available for noninvasive measurement of cerebral venous oxygenation. Our optoacoustic systems provide noninvasive, accurate measurements of the cerebral venous blood oxygenation and will substantially reduce mortality and morbidity of these patients (approximately 2 million per year in the USA alone).
According to the World Health Organization, anemia (low hemoglobin content in blood) afflicts as many as 2 billion people and is the largest global illness adversely affecting mortality and morbidity. At present, anemia (both chronic and acute) is diagnosed using invasive measurements of hemoglobin concentration that involves blood sampling followed by analysis in a clinical laboratory. The optoacoustic platform can provide noninvasive, real-time, accurate measurement of total hemoglobin concentration by direct probing of blood vessels with high contrast and resolution. This can significantly improve care for patients with chronic anemia and for patients undergoing surgical procedures with rapid blood loss.
Another important application of the optoacoustic systems developed by our group is noninvasive diagnostics and management of circulatory shock that utilizes measurements of oxygenation in central veins. A risky, invasive procedure (pulmonary artery catheterization) is currently used for the diagnostics and management of the circulatory shock.B B Moreover, the optoacoustic platform can be used for noninvasive monitoring of concentration of pathologic hemoglobins, as well as for monitoring of blood pressure in arteries, veins, and capillaries.
We built optoacoustic systems for monitoring of these parameters and tested them in pre-clinical and clinical studies. The systems include portable, light-weight, inexpensive, pulsed laser diodes or tunable lasers operating in the near infra-red spectral range.B We developed patient interfaces with highly-sensitive, wide-band optoacoustic probes designed and built for these diagnostic applications. A software package was developed for automatic, real-time, continuous monitoring using measurements at different wavelengths.
At conferences (including the Acoustical Society of America Annual Conference) and in scientific journal papers we reported results of the pre-clinical and clinical tests performed by our group to study the capabilities of the optoacoustic platform for noninvasive monitoring of these important physiological parameters.
Our initial studies were supported by R01 and R21 grants from the National Institutes of Health and grants from the Department of Defense. When we had progressed sufficiently that commercialization became feasible, University of Texas Medical Branch encouraged the formation of Noninvasix, Inc., a UTMB-based incubator startup. Noninvasix has licensed several key US and international patents on optoacoustic monitoring, sensing, and imaging. The startup received a seed grant from the UTMB business development program and a grant from the Texas Emerging Technology Fund. Recently, we received additional finding from the NIH and DOD for development of optoacoustic platform. B At present, our group has active grant and contract support for the development and commercialization of this novel diagnostic modality in the amount of $4 million from the federal funding agencies, Texas Emerging Technology Fund, and private investors.
Drs. Esenaliev and Prough are co-owners of Noninvasix, Inc., the UTMB-based startup that has licensed the rights to optoacoustic monitoring, sensing, and imaging technology.