Pulse Wave Analyzer Spontaneous Respiration Elimination
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Solution Overview
Problem
Existing methods for calculating respiratory variation as an index for circulatory dynamics in subjects assisted by an artificial respirator suffer from low accuracy, particularly when spontaneous respiration occurs, due to the inclusion of unit pulse waves with varying amplitudes that are not accurately accounted for.
Innovation Solution
A pulse wave analyzer that acquires both pulse waves and respiration information, detects spontaneous respiration and its end-tidal phase, and eliminates unit pulse waves generated immediately after the end-tidal phase to improve the calculation of respiratory variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If respiratory variation is calculated using all pulse waves in mechanically ventilated patients, then the calculation can be performed, but the accuracy is low when spontaneous respiration occurs due to unit pulse waves with large amplitude variations
Solution Approach 1:
The patent extracts and eliminates unit pulse waves generated immediately after the end-tidal phase of spontaneous respiration from the pulse wave signal. By removing these specific pulse waves that cause large amplitude variations, the calculation of respiratory variation becomes accurate even when spontaneous respiration occurs during mechanical ventilation
Solution Approach 2:
The patent dynamically adjusts the pulse wave analysis by detecting spontaneous respiration events and selectively eliminating only the affected unit pulse waves. This dynamic approach allows the system to maintain accuracy for respiratory variation calculation whether the patient is breathing spontaneously or being fully mechanically ventilated
2Measurement precision
If unit pulse waves generated after end-tidal phase are eliminated, then accuracy of respiratory variation calculation is improved, but the device complexity increases due to additional detection and elimination mechanisms
Solution Approach 1:
The patent performs preliminary detection of the end-tidal phase of spontaneous respiration before calculating respiratory variation. By identifying and marking the timing of end-tidal phases in advance, the system can efficiently eliminate the subsequent unit pulse waves without adding significant computational complexity during the main calculation process
Data Source
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AI summary
A pulse wave analyzer includes: a pulse wave acquirer which is configured to acquire a pulse wave of a subject; a respiration information acquirer which is configured to acquire respiration information of the subject; and an analyzing section which includes: a detector which, based on the respiration information, is configured to detect that spontaneous respiration is generated, and to detect an end-tidal phase of the spontaneous respiration; and an eliminator which is configured to eliminate a unit pulse wave that, in the pulse wave, is generated immediately after the end-tidal phase of the spontaneous respiration, from the pulse wave, wherein the analyzing section is configured to calculate a respiratory variation from the pulse wave from which the unit pulse wave has been eliminated.