Cardiac Function Measurement via Pump Flow Rate Comparison
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Solution Overview
Problem
Current cardiac function measurement systems face challenges in accurately determining cardiac recovery during extracorporeal cardiopulmonary support due to difficulties in measuring cardiac output, especially when the flow rate sensor is not positioned near the heart, leading to potential early or late withdrawal of the extracorporeal circulator, which can result in adverse complications.
Innovation Solution
A cardiac function measurement system that calculates a withdrawal reference flow rate based on pump discharge pressure and compares it with a measured blood transfer flow rate to determine the appropriate timing for extracorporeal circulator withdrawal, using a computer program to quantify the cardiac output and display the results for visual confirmation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow rate sensor is attached to the catheter and delivered to the vicinity of the heart, then the cardiac output measurement accuracy is improved, but the device complexity and measurement difficulty increase
Solution Approach 1:
The patent uses an intermediary approach by measuring the flow rate of blood transferred from the pump (which is easier to access) and using this as a proxy to evaluate cardiac function. Instead of directly measuring cardiac output near the heart, the system measures the pump's blood transfer flow rate and compares it with a reference flow rate to indirectly assess cardiac recovery, thereby avoiding the complexity of positioning sensors near the heart.
2Object-affected harmful factors
If the extracorporeal circulator is withdrawn early, then the complications from anticoagulant therapy are reduced, but the risk of heart failure increases
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the blood transfer flow rate and comparing it with the reference flow rate. This provides real-time feedback on cardiac function recovery, allowing clinicians to make informed decisions about the optimal withdrawal timing. The system updates the assessment continuously, enabling dynamic adjustment of the withdrawal decision based on the patient's actual cardiac recovery status.
Solution Approach 2:
The patent performs preliminary assessment of cardiac function by establishing a reference flow rate before extracorporeal circulator withdrawal. By pre-calculating the reference flow rate based on pump characteristics and blood properties, the system prepares the necessary baseline data in advance, enabling accurate real-time comparison and timely withdrawal decision-making.
3Reliability
If the extracorporeal circulator is withdrawn late, then the heart function recovery is ensured, but the complications from prolonged anticoagulant therapy increase
Solution Approach 1:
The continuous monitoring and comparison mechanism provides ongoing feedback that detects when cardiac function has sufficiently recovered, signaling the optimal withdrawal time. This prevents both premature and delayed withdrawal by maintaining real-time awareness of cardiac status through flow rate comparison.
4Device complexity
If the flow rate sensor is not delivered to the vicinity of the heart, then the device complexity is reduced, but the cardiac output measurement accuracy deteriorates
Solution Approach 1:
The patent employs an intermediary measurement strategy by using the pump's blood transfer flow rate as a surrogate for direct cardiac output measurement. This approach maintains device simplicity while achieving accurate cardiac function assessment through indirect measurement and reference comparison.
Solution Approach 2:
The patent replaces the mechanical approach of positioning a flow rate sensor near the heart with a computational approach. Instead of physically placing the sensor in the difficult-to-reach location, the system uses mathematical comparison between the measured pump flow rate and the calculated reference flow rate to achieve accurate cardiac function evaluation.
Data Source
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AI summary
[Problem] Provided are a cardiac function measurement system, an extracorporeal circulator, and a cardiac function measurement program that are capable of determining recovery of a cardiac function of a patient with high accuracy. [Means for Resolution] A cardiac function measurement system 10 detects a rotation speed of a pump 3 configured to remove blood from a patient P and return the blood to the patient P, determines a discharge pressure of the pump 3 based on the rotation speed, determines a withdrawal reference flow rate indicating a theoretical flow rate of the blood transferred from the pump 3 based on the discharge pressure, determines a measured blood transfer flow rate indicating a realistic flow rate of the blood based on a measurement result of a flow rate measurement unit configured to measure a flow rate of the blood transferred from the pump 3, and determines a withdrawal timing of an extracorporeal circulator 1 based on a comparison between the withdrawal reference flow rate and the measured blood transfer flow rate.