Pulse Oximetry Signal Processing for Short Desaturation Detection
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Solution Overview
Problem
Conventional pulse oximeters fail to accurately detect short duration desaturation events and underreport the occurrence and severity of apnea, hypopnea, and RERA events due to noise reduction techniques that distort and delay desaturation event timing, which are critical for diagnosing sleep-related breathing disorders.
Innovation Solution
An enhanced pulse oximetry system that processes unconditioned oximetry data in conjunction with multiple physiological sensors to identify respiratory events, assign confidence scores, and provide real-time and batch-mode analysis for precise detection of desaturation events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pulse oximeters apply heavy filtering and averaging to remove artifacts and stabilize readings, then measurement stability and false alert reduction are improved, but detection accuracy of short duration desaturation events deteriorates
Solution Approach 1:
The patent segments the signal processing into two distinct pathways: a filtered pathway for stable baseline monitoring and an unfiltered pathway for capturing transient events. The unfiltered oximetry data is preserved separately and processed independently to detect short-duration desaturation events that would otherwise be smoothed out by conventional filtering.
Solution Approach 2:
The system performs preliminary action by storing unfiltered oximetry data alongside filtered data before final analysis. This allows the system to have both stable baseline readings and preserved transient event data available for simultaneous review, enabling detection of short events without compromising overall measurement stability.
2Reliability
If conventional pulse oximeters apply time averaging and noise reducing signal processing techniques, then false alerts are reduced and stable readings are provided, but occurrence and severity of apneic events are under-reported
Solution Approach 1:
The patent merges two processing approaches by simultaneously maintaining both filtered and unfiltered oximetry data streams. The filtered data provides stable baseline monitoring with reduced false alerts, while the unfiltered data preserves transient desaturation events. Both streams are analyzed together to provide a complete picture of respiratory events.
Solution Approach 2:
The system changes the processing parameter by applying different levels of filtering to different data streams. The unfiltered stream retains high-frequency components necessary for detecting short events, while the filtered stream provides stable baseline values. This parameter differentiation allows simultaneous achievement of false alert reduction and event detection.
3Reliability
If conventional pulse oximeters delay alerts to allow settling of abrupt SpO2 changes, then false alerts are prevented, but timing accuracy of desaturation events is lost
Solution Approach 1:
The patent introduces an intermediary approach by using unfiltered data as a parallel monitoring channel. While filtered data undergoes settling delays, the unfiltered data immediately captures abrupt SpO2 changes. This intermediary unfiltered stream serves as a real-time detector that does not require settling time, preserving event timing accuracy.
Solution Approach 2:
The system dynamically switches between filtered and unfiltered data streams based on event detection needs. For stable baseline monitoring, filtered data is used with its inherent delay tolerance. For abrupt change detection, the system immediately processes unfiltered data to capture precise event timing, creating a dynamic adaptive processing approach.
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
The system enhances the detection of sleep disordered breathing by accurately identifying short and long duration desaturation events with high sensitivity and specificity, providing clinicians with a nuanced picture of respiratory disturbances.
Implementation Method 1
Oxygen is measured as saturated oxygen level (SpO2) which is the percentage of oxygen bound hemoglobin (oxyhemoglobin) relative to total hemoglobin
Data Source
AI summary
The present specification describes a system and method of detecting sleep disordered breathing, that includes acquiring a set of unconditioned sleep test data that includes oximetry data and at least one other physiological sensor data; sampling the set of unconditioned sleep test data; storing the sampled set of unconditioned sleep test data; receiving, through a display, an input indicative of a degree of analyzing to be applied to the sampled set of unconditioned sleep test data; based on said input, applying a corresponding degree of analyzing to the unprocessed sleep test data to generate processed sleep test data; and visually displaying the processed sleep test data.