Field Testing of a Wireless Wearable Reflectance Pulse Oximeter
`R.J. Duckworth, Ph.D.†, Y. Mendelson, Ph.D.*, G. Comtois, B.Sc.*
`†Department of Electrical and Computer Engineering, *Department of Biomedical Engineering,
`Worcester Polytechnic Institute, Worcester, MA 01609.
`
`ABSTRACT
`
`EVALUATIONS
`
`A wireless wearable pulse oximeter has been developed based on a small forehead-mounted sensor.
`The battery-operated device employs a lightweight optical reflectance sensor and incorporates an
`annular photodetector to reduce power consumption. The system also has short range wireless
`communication capabilities to transfer arterial oxygen saturation, heart rate, body acceleration, and
`posture information to a PDA carried by military and civilian first responders.
`The PDA can monitor multiple wearable pulse oximeters simultaneously and allows medics to collect
`vital physiological information to enhance their ability to extend more effective care to those with the
`most urgent needs. The system can be programmed to alert on alarm conditions, such as sudden
`trauma, or physiological values out of their normal range. It also has the potential for use in combat
`casualty care, such as for remote triage, and for use by first responders, such as firefighters. This
`paper will describe the field testing and clinical utility of this wearable system, and compare its
`performance with that of conventional pulse oximeters.
`
`§ Reference HR and SpO2 measurements were obtained
`simultaneously from the wearable and Masimo SET(cid:210) pulse
`oximeters.
`
`§ Two reflectance-mode sensors were positioned using an elastic
`headband on each side of the forehead above the eyes.
`
`§ Readings were recorded from healthy volunteers during rest,
`walking, and stair climbing.
`
`§ Recordings were acquired during voluntary breath holding
`maneuvers.
`
`SYSTEM CONFIGURATION
`
`§ Sensor Module
`§ Small battery-operated forehead-mounted optical reflectance sensor.
`§ RF transmitter to transmit data to a belt-worn receiver module.
`
`RESULTS
`
`Medic
`
`
`
`Resting Resting
`
`
`
` Walking Walking
`
`
`
` Resting Resting
`
`
`
`RestingResting
`
`
`
`Climbing Stairs Climbing Stairs
`
`
`
` Resting Resting
`
`Simultaneous recordings of HR (upper trace) and SpO2 (lower trace) from the wearable (blue) and Masimo
`SET(cid:210) (red) pulse oximeters for different activities.
`
`DISCUSSION
`
`§ Wearable mobile platform:
`§ Implementing a short-range wirelessly-linked personal area network.
`§ Transmitting vital information to command units and remote off-site base stations.
`§ Compact, low-power, small, light-weight, unobtrusive, and wearable.
`
`§ Preliminary results show that SpO2 and HR readings are within an acceptable
`clinical range; response time of the wearable pulse oximeter is adequate for detecting
`hypoxic episodes.
`
`§ Advantages:
`§ Monitor vital signs during training exercises and combat missions.
`§ Help emergency first-responders operating in harsh and hazardous environments.
`§ Helping to save lives.
`§ Enables medics to commence triage within moments after soldier injury
`§ Medics can receive accurate information about severity and progression of injury
`§ Effective intervention: optimize available treatment and evacuation.
`
`§ Receiver Module
`§ Receives digital data from sensor module.
`§ Processes data in real-time by a low-power microcontroller.
`§ Transmits arterial oxygen saturation (SpO2), heart rate (HR), body
`acceleration and posture information to a PDA.
`
`§ PDA Module
`§ Can monitor multiple wearable sensors.
`§ Allows medics to collect vital physiological information and extend more effective care.
`§ Can be programmed to alert medics when physiological conditions are out of normal range.
`
`90 mm
`
`˘ = 30 mm
`
`50 mm
`
`Receiver Module
`
`Sensor Module
`
`Simultaneous hypoxic recording of SpO2 (upper trace) and HR (lower trace)
`from the wearable (blue) and Masimo SET(cid:210) (red) pulse oximeters.
`
`SUMMARY
`
`PDA INTERFACE
`
`§ Displays SpO2, HR, body
`acceleration and posture information.
`
`§ Carried by military and civilian first
`responders.
`
`§ Alerts carrier during alarm conditions,
`such as sudden trauma, or when
`physiological values are out of normal
`range.
`
`§ Can be used to monitor multiple
`casualties
`
`Preliminary testing of a new wearable reflectance pulse oximeter show that it
`could be used to monitor accurate SpO2 and HR from a forehead sensor. The
`system would allow medics to collect vital physiological information in the
`field. This information could enhance the ability of first responders to extend
`more effective medical care, thereby saving the lives of critically injured
`persons. The system is presently undergoing additional field testing to further
`evaluate its functionality and to determine future improvements.
`
`ACKNOWLEDGMENT
`
`This work is supported by the U.S. Army Medical Research and Material
`Command under Contract No. DAMD17-03-2-0006. The views, opinions
`and/or findings are those of the author and should not be construed as an
`official Department of the Army position, policy or decision unless so
`designated by other documentation.
`
`Simultaneous 4s time-series recordings of HR (upper trace) and SpO2 (lower trace) from the wearable (blue)
`and Masimo SET(cid:210) (red) pulse oximeters. Recording were repeated every 2hr over a 14hr period.
`
`MASIMO 2005
`Apple v. Masimo
`IPR2022-01292
`
`