Remote Physiological Monitoring

Remote physiological monitoring, in one form or another, has a long, established history in aviation and space applications.

Gear intended to fit under or on clothing to measure various parameters of bodily function and environmental conditions has existed since the late 1940s. Beginning soon after World War II, the U.S. Air Force, the National Advisory Committee on Aeronautics (NACA), and its successor, the National Aeronautics and Space Administration (NASA), built a series of rocket-powered experimental aircraft to explore flight at very high speeds and altitudes. In 1947, Charles Yeager flew the X-1 past mach 1; in 1956, the X-2 flew at nearly mach 3. Two years later an X-2 test pilot set a world altitude record of nearly 126,000 feet. By 1967 a pilot flying North American Aviation's X-15 had reached Mach 6.7, soaring 60 miles above the Earth's surface.Test pilots flying in the late 1950s and after needed special suits, helmets, and oxygen supply systems to stay alive, and scientists needed to collect data on human performance in their cockpits. Physiologic data was not collected consistently throughout the test flight programs, due to resistance by test pilots to becoming "guinea pigs.'' When collected, this information was generally recorded in the aircraft, and collected for study after landing.

Collecting data on human bodily function was also a vital part of research in the space program. In 1958, the Mercury program ushered in the first group of physicians specifically assigned to care for astronauts. NASA decided that monitoring astronaut physiology in real time was of critical importance; therefore physiologic data collected by sensors was included in spacecraft telemetry from the beginning of the space program. These data included heart rate and rhythm, respiration and core and skin temperature. In the 1960s, Hamilton-Standard, now part of United Technologies Corp., developed a series of space suits designed to accept NASA-developed biometric-measuring gear. These suits were used in the Apollo, Skylab, and Space Shuttle programs. Data from these systems was recorded during flight and added to other telemetry sent to the ground. To these systems the Russians added (on the space station, not the suits), a blood analyzer, built by Daimler-Benz in Germany, which automatically sent blood chemistry results to ground control from the Mir space station.

Medical researchers have successfully demonstrated, on a small scale, the potential of physiological monitoring technology to aid in the remote monitoring of personnel functioning in extremely inhospitable environments. Examples of this include trials of biosensors designed and built by FitSense Technology Corporation Inc.

Working at the NASA-funded Commercial Space Center of Yale University's Department of Surgery, researchers led by Dr. Richard Satava organized climbing expeditions on Mount Everest, during the climbing seasons of 1998-1999, in order to demonstrate the reliability of FitSense biometrics gear and its value to the health maintenance of people in remote environments. Three climbers wore sensors measuring heart rate, skin temperature, core body temperature, and activity level, as well as a global positioning system (GPS) receiver to determine location. Data from these devices were transmitted to the Everest Base Camp and relayed to Yale University. The outcome measures were correlated via time-stamp identification. Sensor availability ranged from 78% to 100%. The researchers concluded that this application of biosensor technology was feasible, but that improvements in reliability and robustness were needed.

FitSense also equipped 16 Marines at Quantico VA, and nine U.S. Army Rangers at Fort Benning GA, with biosensors during 10-day war fighting exercises in 1998, 1999, and 2000. The sensors were taped on or otherwise worn by soldiers wearing standard-issue battle dress uniforms (BDUs). The Rangers' biosensors transmitted data in real time to a command post; the Marine's sensor data was recorded by a device worn by each soldier. The company reported 100% availability of sensors, with reporting accuracy of 97% (Blackadar, 2001). When interviewed, the company's CEO noted that pulse oximeters proved problematic at first, and the company expended a good deal of effort to improve them.

As shown by these trials, these types of sensors are not intended exclusively for the military. Law enforcement, medical surveillance, search and rescue, and public health applications offer possible uses. The idea common to all these applications is to enable a control center to determine whether and how severely people under its control are injured or otherwise disabled. Possible scenarios this technology can be applied to include a military command post watching over soldiers embarking on a reconnaissance mission, a police unit commander watching over officers who are dispersed over a wide area, or a fire department battalion chief keeping a close watch on fire fighters advancing into a burning building. A photo showing the transceivers appears in Figure 27.1.

figure 27.1 Transceivers. (Courtesy of FitSense Technologies.)

One drawback of this equipment is its expense. It costs thousands of dollars to outfit a soldier with this type of equipment.

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