Determining who needs medical care at the scene of a disaster is still an old-fashioned procedure – medical personnel must check body temperature, heart rate, and muscle movement, a process that can take between 3-5 minutes per person.
Now, a group at the US Department of Homeland Security’s Science & Technology Directorate (DHS S&T) is developing a new device called the Standoff Patient Triage Tool (SPTT), that could reduce that diagnosis time to 30 seconds per person.
The SPTT takes key physiological readings, such as pulse, body temperature and respiration from 5 to 40ft away from a patient, using a laser Doppler vibrometer (LDV) that measures the velocity and displacement of vibrating objects.
The laser beam from the LDV is directed at the surface of interest, and the vibration amplitude and frequency are extracted from the Doppler shift of the laser beam frequency due to the motion of the surface.
An algorithm then converts those data points into measurements emergency teams can use to assess a patient’s medical condition.
With the help of collaborators at Washington University, the researchers have found that the best place to capture strong readings of vital signs is on the carotid artery, though strong signals have been obtained from the head, chest, abdomen, and even a foot.
Researchers are also testing whether readings could be taken when someone is lying in an awkward position, or wearing multiple layers of clothing.
So far, the results are encouraging.
The researchers now aim to develop a hand-held SPTT unit, about the size of a legal notebook and as a thick as a ream of paper.
Achieving this will require hardening of the unit, and further testing of the optical stabilisation technology to make sure the unit can function despite a user’s arm and hand movements.
The system should be commercialised in 2010.