Ventilation Apparatus Respiratory Gas Content Determination
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Solution Overview
Problem
Existing ventilation devices struggle to accurately determine breathing gas content in the respiratory tract of artificially ventilated patients, leading to signal drift and potential hiding of medically relevant breathing stacks.
Innovation Solution
The procedure involves using a breathing intensity value to determine the breathing gas content for the next breath, based on the difference in breathing gas quantity between previous breaths, to prevent signal drift while avoiding the masking of relevant ventilation events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow sensors are used to continuously record and integrate respiratory gas flows to determine respiratory gas content, then measurement precision is improved, but signal drift occurs due to calibration deficiencies and manufacturing inaccuracies
Solution Approach 1:
The system uses feedback by comparing the determined respiratory gas content with expected physiological ranges and adjusting the initial value accordingly. The control device continuously monitors the integrated flow values and modifies the starting point of integration to maintain accuracy over time, preventing drift accumulation while preserving measurement precision.
Solution Approach 2:
The patent changes the parameter of initial value selection dynamically. Instead of using a fixed initial value, the system adapts the initial value based on the detected flow asymmetry and drift patterns. This parameter change allows the system to compensate for sensor calibration issues and manufacturing variations, maintaining reliable measurements without sacrificing precision.
2Reliability
If the respiratory gas content determination is reset to zero at the end of each breath to prevent drift, then signal stability is improved, but medically relevant events like breathing stacks are masked
Solution Approach 1:
The system implements dynamic initial value adjustment rather than a static reset-to-zero approach. The initial value for integration is adaptively modified based on detected drift patterns and physiological plausibility checks. This dynamic approach maintains signal stability by preventing drift while preserving information about abnormal ventilation events such as breathing stacks, where the respiratory gas content should naturally accumulate.
Solution Approach 2:
The system performs preliminary assessment of flow symmetry and drift trends before determining the appropriate initial value for the next integration cycle. By anticipating potential drift issues and adjusting the initial value in advance, the system prevents both drift accumulation and information loss about clinically relevant events.
3Productivity
If flow sensors are exposed to moisture from respiratory gas to perform continuous measurement, then measurement capability is improved, but calibration deficiency increases due to condensation
Solution Approach 1:
The system uses feedback mechanisms to detect calibration drift caused by moisture exposure. By continuously monitoring the relationship between inspiratory and expiratory flow measurements and comparing them against expected physiological patterns, the system identifies when moisture condensation has affected sensor accuracy and adjusts the initial value accordingly, maintaining continuous measurement capability while compensating for calibration degradation.
Data Source
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AI summary
The present invention relates to a method for determining a respiratory-gas content in a respiratory tract, which content is present in the respiratory tract of an at least partially artificially ventilated patient following a plurality of breaths performed with the involvement of a ventilation apparatus, wherein the plurality of breaths include at least one earlier number of breaths and at least one follow-up breath following the earlier number of breaths; wherein the earlier number of breaths include an earlier breath or a plurality of successive earlier breaths; wherein the method comprises quantitative detection of inspiratory and expiratory respiratory-gas flows (S10) by at least one respiratory-gas flow sensor and summation of detected inspiratory and expiratory flow values to form the respiratory-gas content (S110) in the respiratory tract; wherein a respiratory tract content starting value, at which the determination of the respiratory-gas content in the respiratory tract for the follow-up breath starts, depending on a difference in respiratory-gas amount between an inspiratory respiratory-gas amount supplied to the patient during an earlier number of breaths and an expiratory respiratory-gas amount output by the patient during the earlier number of breaths, is set to a reset starting value (S140), which is closer to zero than to a difference value that quantitatively provides the respiratory-gas amount difference, or is set to a continuity starting value (S100), which is closer to the difference value than to zero.