High-Flow Respiratory Therapy Gas Measurement Dilution Correction
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Solution Overview
Problem
Non-sealed respiratory flow systems, such as high flow respiratory therapy, cause gas dilution during exhaled gas measurements, leading to inaccurate assessments due to the flushing mechanism, which underestimates or overestimates gas concentrations, particularly in capnography, affecting the diagnosis of patient conditions.
Innovation Solution
A system and method for compensating gas measurements by estimating flow rate dilution using a respiratory flow therapy system, exhaled gas monitoring system, and processing arrangement to determine a compensated exhaled gas measurement, incorporating sensors and hardware computer processors to calculate patient-only contributions to expiratory flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high flow respiratory therapy is applied to deliver therapeutic gas flows, then gas delivery effectiveness is improved, but gas measurement accuracy deteriorates due to flushing and dilution of exhaled gases
Solution Approach 1:
The system continuously monitors exhaled gas concentrations and uses this feedback to dynamically adjust the therapeutic gas flow rate, creating a closed-loop control system that maintains measurement accuracy while optimizing therapy delivery
Solution Approach 2:
The system changes the flow rate parameter dynamically based on real-time gas concentration measurements, adjusting the therapeutic gas delivery to minimize dilution effects while maintaining therapeutic effectiveness
2Speed
If flow rate is increased to enhance therapy delivery, then gas delivery performance is improved, but gas concentration measurement accuracy deteriorates due to increased dilution
Solution Approach 1:
The system transitions from static flow rate delivery to dynamic flow rate adjustment, continuously adapting the flow rate based on real-time gas concentration measurements to maintain optimal therapeutic effect while minimizing measurement interference
Solution Approach 2:
The flow rate parameter is dynamically changed based on measured gas concentrations, allowing the system to optimize between delivery performance and measurement accuracy by adjusting the flow rate in real-time
3Ease of operation
If non-sealed respiratory flow systems are used to allow natural breathing, then patient comfort is improved, but measurement reliability deteriorates due to gas flushing and non-uniform distribution
Solution Approach 1:
The system uses continuous feedback from gas concentration sensors to compensate for the non-uniform gas distribution caused by the non-sealed interface, calculating corrected measurements that maintain reliability while preserving patient comfort
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
Accurately compensates for gas dilution errors during respiratory flow therapy, enabling precise exhaled gas measurements, including CO2, O2, N2, and nitrous oxide, thereby improving clinical assessments and reducing the need for invasive monitoring.
Implementation Method 1
alveolar CO2 is mixed with fresh gas delivered via the cannula, causing a dilution of exhaled CO2 that is sampled and measured
Data Source
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AI summary
The present disclosure relates to determining a corrected exhaled gas measurement during high flow respiratory therapy. Measuring exhaled gas concentration during high flow respiratory therapy is difficult and inaccurate due to a phenomenon known as flushing. The high flows delivered to the patient flush the dead space in the conducting airways, which causes a dilution effect that results in underestimated or overestimated exhaled gas measurement depending on the gas composition delivered by the high flow system. This can lead to incorrect clinical measurements and diagnoses. Various algorithms are disclosed herein to account for the dilution effect caused by flushing, allowing for the method of measuring gas concentrations to still be used accurately for clinical measurements.