Sensors with Down-to-Earth Uses to Monitor Astronauts' Metabolism in Space

A noninvasive, needle-free system that uses light to measure tissue oxygen and pH will soon be an alternative to the painful use of needles to draw blood and cumbersome equipment used to determine metabolic rate.

Researchers from the University of Massachusetts Medical School (UMMS; Worcester, USA) and the U.S. National Aeronautics and Space Administration (NASA) Johnson Space Center (Houston, TX, USA) are developing the Venus prototype system that will have the capability of measuring blood and tissue chemistry, metabolic rate (as measured by oxygen consumption), as well as other parameters. Placed directly on the skin, the 10 x 5 cm sensor uses near infrared light to take the necessary measurements. Blood in capillary vessels absorbs some of the light, but the rest is reflected back to the sensor.

The monitor analyzes the reflected light to determine metabolic rate, along with tissue oxygen and pH. The device measurements are not impacted by skin color or body fat. Researchers are also adapting the sensor for integration into spacesuits by reducing its size, increasing its accuracy in measuring metabolic rate, and developing the capability to run the system on batteries. These activities will also speed its application in helping to care for patients on Earth. The development of the sensor and the associated portable monitor are being funded by the U.S. National Space Biomedical Research Institute (NSBRI; Houston, TX, USA).

"Tissue and blood chemistry measurements can be used in medical care to assess patients with traumatic injuries and those at risk for cardiovascular collapse," said Babs Soller, M.D., who leads NSBRI's Smart Medical Systems and Technology team and is also a professor of anesthesiology at UMMS. "The measurement of metabolic rate will let astronauts know how quickly they are using up the oxygen in their life-support backpacks. If spacewalking astronauts run low on oxygen, the situation can become fatal."

"The neat thing about the work being done is that it is a two-for-one deal," said former NASA astronaut and NSBRI user panel chairman Leroy Chiao, Ph.D. "Not only is this research going to help future astronaut crews and operations, it has very real benefits to people on the ground, especially to people in more rural areas."

On Earth, there are several areas of health care that could benefit from the Venus, such as patients treated by emergency personnel on ambulances, on the battlefield, and other urgent care situations. It will allow doctors to more efficiently monitor pediatric and intensive care unit patients. Athletes and physical therapy patients also stand to gain from the technology's ability to measure metabolic rate and to assist in determining the level of activity or exercise that is most beneficial to the individual.

Related Links:
University of Massachusetts Medical School
U.S. National Aeronautics and Space Administration
U.S. National Space Biomedical Research Institute