Robust, Speckle-Tolerant, Handheld Non-Contact Vital Sign Monitor with Photonics IC

Technical Abstract

To aid Combat Medic’s triage of injured Warfighters, the non-contact Vital Signs Monitor (ncLVSM) is a chest-mount device that autonomously retrieves select vital signs of the Warfighter while the medic tends the injuries. The vital signs to be monitored include the heart rate (HR), respiration rate (HR), arterial waveform (AWF), and the AWF-derived systolic pressure (SBP) and diastolic pressure (DBP), while the core body temperature (Tc) derives from serial measurements of HR via the ECTemp algorithm. In Phase I, we iteratively investigated various component technologies and arrived at the design of the ncLVSM that supports small form factor similar to that of smartphones, thanks to the Government’s invaluable guidance in adopting photonic integrated circuit (PIC) in the ncLVSM while eliminating the conventional free space optics. We further designed, modeled, and validated in silico a novel laser beam projector using PIC-integrated cascaded Mach-Zehnder Interferometers (MZIs) that involves no moving parts. Combined with plastic-lens based laser projection and collection modules, the resultant ncLVSM design supports light-weight, robust operations in the harsh battlefield environment. With the designed-in human pose estimation, the ncLVSM is capable of automatically locating the injured Warfighter, pinpoint his/her pose and pulse points, and retrieve raw waveforms using laser following a preset guidelines, resulting in the retrieval and display of vital signs after signal conditioning, processing, and analysis. In Phase II, component technologies are to be validated experimentally, leading to the final prototype build which will be used to collect vital signs in human subject studies after appropriate IRB approval.

Commercial Benefits

Potential commercial benefits resulting from the successful execution of the Phase II program includes: A non-contact vital signs monitor capable of continuous tracking, pointing, and measurement of vital signs like heart rate and respiration rate, all without any single thread of wire or cable dangling away from the patient. The device will be especially impactful in the neonatal care units as no physical contact need be made with the highly sensitive skin of the babies. Another potential product is the holy grail of non-contact measurement of blood pressures. The proposed technology offers the potential of non-contact assessment of systolic and diastolic pressures even though the challenge of measurement calibration remains to be solved in the Phase II program. Other potential commercial benefits include cardiac activity monitor capable of retrieving fine cardiac signatures in the presence of patient’s gross physical movements. This is to be achieved through developmental work in the Phase II program on the front of signal processing. If successful, we can empower the product to measure cardiac response of soldiers or athletes undertaking strenuous physical activities like running.

Key words:

Vital Signs, Laser Vibrometer, Pose Estimation, Pulse Point, Photonic Integrated Circuit