Blood Purification Apparatus Recirculation Rate Calculation
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Solution Overview
Problem
Conventional blood purification apparatuses fail to effectively address blood recirculation during dialysis when blood flow through the access vessel is less than the extracorporeal circulation flow, leading to reduced purification efficiency and unreliable blood concentration data.
Innovation Solution
A blood purification apparatus and method that calculates an ideal extracorporeal circulation flow to minimize recirculation by using a predetermined indicator and hematocrit sensors to detect recirculation rates, adjusting the blood pump to maintain a recirculation rate below a predetermined value, and determining the shunt flow to optimize blood flow through the access vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the extracorporeal circulation flow is increased to improve blood purification efficiency, then the purification rate increases, but blood recirculation occurs when the access vessel flow is insufficient, reducing purification efficiency
Solution Approach 1:
The system performs preliminary detection of blood recirculation by monitoring hematocrit concentration changes before recirculation significantly impacts purification efficiency. By detecting the indicator (concentration agglomeration) and calculating recirculation rate in advance, the system can alert operators to adjust needle positions or circulation flow before purification efficiency deteriorates
Solution Approach 2:
The system continuously monitors blood hematocrit concentration at different points in the circulation system and uses this feedback to calculate recirculation rate. This real-time feedback mechanism allows the system to detect when recirculation is occurring and provide information for corrective action to maintain optimal purification efficiency
2Measurement precision
If blood recirculation is detected using conventional methods, then recirculation rate can be measured, but no corrective measures are provided to address the underlying cause
Solution Approach 1:
The system provides feedback not only on the recirculation rate measurement but also on the likely cause (access vessel stenosis or insufficient flow). This feedback loop includes alerting operators to the problem and suggesting corrective actions, making the system easier to operate by guiding users through the troubleshooting process
Solution Approach 2:
The system performs self-diagnosis by automatically detecting recirculation, calculating the recirculation rate, and identifying the probable cause. This self-service capability reduces the operational burden on users by automating the detection and initial analysis functions
3Speed
If blood flow through the access vessel is insufficient due to stenosis, then the blood purification system cannot maintain required circulation flow, but increasing pump power to compensate causes more recirculation
Solution Approach 1:
The system performs preliminary detection of recirculation conditions by monitoring hematocrit concentration patterns. By identifying recirculation early through indicator detection (concentration agglomeration), the system can alert operators to reduce pump flow or adjust needle positions before excessive recirculation develops from forcing high flow through a stenotic access vessel
Solution Approach 2:
The system replaces purely mechanical flow control with a sensor-based detection and calculation system. By using hematocrit sensors to detect concentration changes and calculate recirculation rate, the system provides information-based control that complements mechanical pump control, allowing operators to make informed decisions about flow management
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
The solution effectively reduces blood recirculation, improving blood purification efficiency and providing reliable blood concentration data by calculating and maintaining an ideal extracorporeal circulation flow, ensuring no significant recirculation occurs during treatment.
Implementation Method 1
a device for detecting the concentration of the extracorporeally circulating blood such as a blood volume measuring device (hematocrit sensor)
Implementation Method 2
The hollow fibers are formed with a plurality of micropores on its walls, and the waste products and the like of the blood flowing through the hollow fibers pass through a blood purification membrane
Data Source
AI summary
A blood purification apparatus includes a blood circuit having arterial and venous blood circuits, a blood pump, a blood purifying device, an indicator applying device that applies a predetermined indicator to the blood flowing extracorporeally through the blood circuit, a detecting device that detects the indicator applied by the indicator applying device, an arithmetic device that calculates, based on the indicator detected by the detecting device, a recirculation rate, and a calculating device that calculates an ideal extracorporeally circulating blood flow that results in the recirculation rate being no more than a predetermined value when the recirculation rate calculated by the arithmetic device is greater than the predetermined value. The recirculation rate is a proportion of a recirculated blood flow, which is reintroduced to the patient from the venous blood circuit and directed again to the arterial blood circuit, relative to an extracorporeally circulating blood flow.