Blood Pressure Measurement Apparatus With Dynamic Threshold
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Solution Overview
Problem
Existing blood pressure measurement techniques for patients with obstructive sleep apnea (OSA) often result in excessive measurements, disrupting sleep and failing to capture nocturnal blood pressure surges due to manual threshold settings and inadequate timing of measurements.
Innovation Solution
A blood pressure measurement apparatus that includes a determining unit to assess a time-varying condition for initiating measurements, using a variable threshold based on the lowest oxygen saturation level and time-dependent changes to ensure comprehensive data collection over a predetermined period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If blood pressure measurement is started when the blood oxygen saturation level falls below a manually set reference, then blood pressure measurement can detect nocturnal blood pressure surges, but blood pressure measurement is performed a very large number of times with severe OSA patients, significantly inhibiting the subject's sleep
Solution Approach 1:
The patent applies dynamics by making the threshold value variable rather than fixed. The threshold value changes over time during the measurement period, being higher in the first half and lower in the second half. This dynamic adjustment allows the system to adapt to the natural progression of sleep stages and apnea events, reducing unnecessary measurements during deep sleep while ensuring detection of later surges.
Solution Approach 2:
The patent changes the parameter of threshold value over time. Specifically, the threshold is set to a first value for the first half of the measurement period and a second value (lower than the first) for the second half. This parameter change resolves the contradiction by reducing measurement frequency during early sleep when severe apnea may already have occurred, thereby reducing sleep inhibition while maintaining detection capability for later blood pressure surges.
2Adaptability or versatility
If a threshold value is first set to a relatively high level and the lowest value of the blood oxygen saturation level that appears after the start of measurement is successively stored, then automatic individual adjustment of the threshold value is enabled, but if the most severe low respiration state appears during the initial stage of sleep, blood pressure measurement will not be performed at all thereafter
Solution Approach 1:
The patent applies dynamics by dividing the measurement period into two distinct time phases with different threshold values. The first threshold applies during the first half of the measurement period, and the second (lower) threshold applies during the second half. This dynamic temporal segmentation ensures that even if severe apnea occurs early, the system continues to monitor and detect blood pressure surges in the latter half of the sleep period.
Solution Approach 2:
The patent segments the measurement period into two distinct time intervals: the first half and the second half of the measurement period. Each segment has its own threshold value strategy. This segmentation prevents the single threshold approach from excluding all subsequent measurements after an early severe event, as the second segment with its lower threshold ensures continued detection capability.
3Loss of information
If blood pressure measurement is performed frequently to capture all apnea events, then complete blood pressure variation pattern can be acquired, but the subject's sleep is significantly inhibited
Solution Approach 1:
The patent changes the threshold parameter over time to balance information acquisition and sleep preservation. By setting a higher threshold for the first half and a lower threshold for the second half, the system reduces the number of measurements triggered during early sleep when the subject is most vulnerable to disruption, while still capturing blood pressure variation patterns in the latter half of the sleep period.
Data Source
AI summary
A blood pressure measurement apparatus for measuring blood pressure in a predetermined period includes a blood pressure measuring unit for measuring the blood pressure of a subject, an information acquiring unit for acquiring information that is related to variation in blood pressure and changes in a time-series in the predetermined period, a determining unit for determining whether or not the information acquired by the information acquiring unit satisfies a predetermined condition, and a trigger output unit for, in a case where the determining unit determines that the predetermined condition is satisfied, causing the blood pressure measuring unit to start and execute blood pressure measurement. The predetermined condition is expressed as a function of time that varies and is measured in the predetermined period.