Multi-Sensor Pulse Oximeter Time-Multiplexed Drive Circuit
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Solution Overview
Problem
Current pulse oximeters requiring simultaneous measurements from multiple tissue sites are cumbersome due to extensive hardware multiplication and increased complexity, particularly when integrating motion sensors, leading to inaccurate readings and false alarms from mechanical artifacts.
Innovation Solution
A monitoring device connected to multiple sensors via a single wire pair, where each sensor has an emitter and detector, with drive pulses time-multiplexed to allow parallel connection of detectors to a common terminal pair, reducing hardware requirements and enabling simultaneous, cost-effective measurements across multiple sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple conventional pulse oximeters are used for simultaneous measurements at multiple tissue sites, then measurement coverage is improved, but device complexity and hardware requirements increase extensively
Solution Approach 1:
The patent combines multiple sensors into a single integrated pulse oximeter device. The sensor assembly includes multiple sensor units that can be attached to different tissue sites, and all sensors share common hardware resources including a single cable connection, common signal processing circuitry, and unified control logic. This merging approach enables simultaneous multi-site measurements while avoiding the extensive hardware multiplication that would result from using separate conventional oximeters for each site.
2Productivity
If multiple sensors are integrated into a single device with separate cables, then simultaneous measurements are enabled, but device complexity and cable management become problematic
Solution Approach 1:
The patent merges multiple sensor connections into a single cable assembly. The sensor assembly includes multiple sensors that are electrically connected through a common connector and single cable to the pulse oximeter device. This eliminates the need for multiple separate cables and connectors, significantly reducing cable management complexity while maintaining the ability to perform simultaneous measurements from multiple tissue sites.
3Reliability
If motion sensors are added to detect and compensate for motion artifacts, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent integrates motion detection capability into the existing sensor assembly without adding separate motion sensors. The same light-emitting diodes and photodetectors used for oxygen saturation measurement are utilized to detect motion artifacts by analyzing variations in the light absorption patterns. The control logic processes these variations to distinguish between physiological changes and motion-induced artifacts, thereby improving measurement reliability while avoiding the complexity of integrating additional dedicated motion sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution minimizes additional hardware needs, providing a cost-effective and compact monitoring system capable of continuous non-invasive measurements from multiple sites while reducing motion artifact noise, thus improving the reliability of oxygen saturation readings.
Implementation Method 1
Each sensor comprises at least one light source, i.e. emitter element, for sending an optical signal through the tissue and a photo detector for receiving the signal after transmission through the tissue
Implementation Method 2
a photo detector for receiving the signal after transmission through the tissue
Implementation Method 3
Pulse oximetry is based on the assumption that the pulsatile component of the absorption is due to arterial blood
Data Source
AI summary
The invention relates to a patient measurement device, especially to a pulse oximeter, provided with multiple sensors. In order to reduce the hardware required by a measurement performed through the multiple sensors, a repeating drive pulse sequence is generated, which contains drive pulses for the emitter elements of the plurality of sensors. Furthermore, each drive pulse of the sequence is supplied to a corresponding emitter element and sensor-specific detectors connected in parallel are employed to produce an electric reception signal received at the measurement device.