ALLPCB
Overview
Continuous measurement of vital signs such as heart rate, respiratory rate, and blood oxygen saturation (SpO2) is essential for effective care. The ability to measure multiple parameters simultaneously makes multi-parameter patient monitors increasingly important.
Electronic patient monitors acquire and display physiological data using noninvasive sensors attached to the patient. A key challenge for multi-parameter monitors is achieving a small form factor and low power consumption while maintaining high performance.
Design Context
Traditional bedside monitors are often bulky, tethered by multiple cables, and immobile, which limits their use in mobile care and home-care settings. This has driven demand for compact multi-parameter monitors that connect to patients wirelessly and transmit data to mobile phones, tablets, or PCs.
Texas Instruments (TI) provides a multi-parameter vital-signs front-end reference design that targets compact, low-cost, low-power implementations by integrating the necessary front-end components for acquiring vital-signs data.
Hardware and Front-end Components
The design acquires ECG, SpO2, heart rate, and respiratory rate using the AFE4403 and ADS1292R biosensing front-end integrated circuits. It can be paired with a software-configurable pacer detection module reference design to support pacing-pulse detection, and it supports three temperature sensors with 0.1°C accuracy (TMP117) for skin temperature measurement. Standard wet ECG electrodes are used for ECG measurements, and a transmission-type finger-clip sensor can be used for SpO2.
Raw data are collected by an onboard MSP432P401 microcontroller and transmitted via an isolated universal asynchronous receiver/transmitter (UART) interface at 460.8 kbps to a backend processor or PC. Power can be supplied via a standard USB port or a USB-chargeable lithium-ion battery.
Graphical User Interface
The graphical user interface displays acquired waveforms with a 5-second moving interval and applies basic filtering to remove noise such as common-mode interference from power and lighting. Figure 2 shows ECG, respiration, and SpO2 measurements on a PC, along with heart rate (beats per minute), respiratory rate (breaths per minute), SpO2 percentage, and temperature values.
Conclusion
This reference design facilitates evaluation of interoperating devices. It includes design guidelines, schematics, layouts, and a bill of materials to help accelerate product development, and it supports real-time acquisition of vital-signs parameters.
