Bedside Respiratory Rate Estimation Using Motion Classification
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Solution Overview
Problem
Existing biological state monitoring systems face challenges in accurately estimating respiratory rates due to interference from body motions, which can lead to unreliable output values.
Innovation Solution
A biological state monitoring system that includes load detectors, a body motion determining unit, a respiratory rate estimating unit, and a twitch determining unit to differentiate between actual body motions and twitches, allowing for reliable respiratory rate estimation by adjusting output values based on motion type and duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the respiratory rate estimating unit continuously outputs estimated values based on load detector data, then the productivity of monitoring is improved, but the reliability deteriorates due to body motion interference
Solution Approach 1:
The system dynamically adjusts the output behavior of the respiratory rate estimating unit based on real-time body motion detection. When body motion is detected, the system switches from continuous output to selective output (only during rest periods), making the monitoring adaptive to the subject's state rather than following a fixed continuous pattern
Solution Approach 2:
The invention extracts and separates the body motion detection function from the respiratory rate estimation function. By using a dedicated body motion determining unit that independently analyzes load detector data, the system can identify and exclude contaminated measurement periods, thereby improving reliability without sacrificing continuous monitoring capability
2Productivity
If the system outputs respiratory rate estimates during body motion periods, then the productivity is improved, but the measurement precision deteriorates due to motion artifacts
Solution Approach 1:
The system implements feedback by using the body motion determining unit to continuously monitor the quality of respiratory rate measurements. When body motion is detected, this feedback signal triggers the respiratory rate estimating unit to withhold output, creating a closed-loop control system that automatically adjusts output based on measurement quality
Solution Approach 2:
The body motion determining unit performs preliminary analysis of load detector data to predict potential measurement contamination before respiratory rate estimation occurs. By detecting body motion in advance, the system can prevent inaccurate estimates from being generated or outputted
Data Source
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AI summary
A biological state monitoring system (100, 200) for monitoring a biological state of a subject on a bed (BD) includes: at least one load detector (11, 12, 13, 14) configured to detect a load of the subject on the bed; a body motion determining unit (33) configured to determine whether or not the subject has a body motion, based on a temporal variation of a detection value of the load detector; a respiratory rate estimating unit (34) configured to successively obtain and output estimated values of respiratory rate of the subject, based on the temporal variation of the detection value of the load detector; and a twitch determining unit (35) configured to determine whether or not a body motion is a twitch, based on a duration of the body motion of the subject. In a case that the twitch determining unit determines that the body motion is not a twitch, the respiratory rate estimating unit ceases to output the estimated value of the respiratory rate, or outputs a first estimated value which is the latest among the estimated values obtained in a first period, the first period being directly preceding the body motion and being determined by the body motion determining unit to be a period in which the subject has no body motion. In a case that the twitch determining unit determines that the body motion is a twitch, the respiratory rate estimating unit successively outputs newly obtained estimated values of the respiratory rate.