Noninvasive Heart Rate Monitor
Abstract
The feasibility of obtaining noninvasive heart rate measurements on a chemical warfare garbed subject has been investigated. The device is a portable ultrasonic transceiver which utilizes the Doppler effect to detect movements of the heart wall and blood mass. The periodicity of the heart event is then used to deduce the heart rate measurement. The ultrasonic transmitter and receiver are composite piezoelectric crystals with a reversed-horn section for more efficient energy coupling. The process of imparting and recovering sufficient ultrasound energy through the protective clothing is accomplished without using any wetting agent or acoustic gel. In addition to ultrasonic wave detection, the feasibility of passive recording of the hydrostatic cardiac shock wave has also been studied. The low frequency, short duration vibration of the beating heart can be detected using the same piezoelectric receiver. Heart rate monitors based on these two methods have been constructed. Test results show that heart rate can, indeed, be measured even when the subject is wearing a shirt and a sweater, in addition to the standard chemical warfare garment and wrap. However, both monitors failed to give a reliable or usable heart rate measurement when tested on a moving M113 field ambulance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 31, 1983
- Accession Number
- ADB080266
Entities
People
- Kuo W. Chang
- Ssanlu Y. Chang