Recirculation Detection in Extracorporeal Blood Circuits
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Solution Overview
Problem
Current methods for detecting recirculation during extracorporeal blood treatment are either invasive, require complex procedures, or lack sensitivity and reliability, making it difficult to routinely check the status of vascular access during dialysis.
Innovation Solution
A device that administers a bolus of substitution liquid to change viscosity in the extracorporeal circuit, reducing blood flow rate and compensating with substitution fluid, allowing for pressure changes to detect recirculation with enhanced sensitivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current methods for detecting recirculation are used, then the detection can be performed, but the methods are either invasive, require complex procedures, or lack sensitivity and reliability
Solution Approach 1:
The invention changes the blood flow rate parameter by reducing it to a lower level during the detection phase. This creates significant pressure changes in the extracorporeal circuit that enhance the sensitivity and reliability of recirculation detection without requiring complex procedures or invasive measures.
Solution Approach 2:
The invention replaces complex mechanical detection procedures with a pressure-based detection method. By monitoring pressure changes in the circuit during reduced blood flow, the system achieves reliable recirculation detection through a simpler, less invasive mechanism.
2Measurement precision
If blood flow rate is reduced to enhance pressure changes for detection, then detection sensitivity improves, but the treatment time may be affected
Solution Approach 1:
The invention implements periodic action by alternating between normal blood flow rates during treatment and reduced blood flow rates during detection phases. This allows the system to maintain treatment efficiency during normal operation while enabling precise recirculation detection during brief periodic intervals when blood flow is temporarily reduced.
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 method improves the detection of recirculation by creating significant pressure changes in the venous and arterial branches, enabling more accurate and reliable measurement, thus ensuring better vascular access monitoring during extracorporeal blood treatment.
Implementation Method 1
A device that administers a bolus of substitution liquid to change viscosity in the extracorporeal circuit
Implementation Method 2
allowing for pressure changes to detect recirculation with enhanced sensitivity and reliability
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a device and a method for detecting recirculation for an extracorporeal blood treatment device, and to an extracorporeal blood treatment device having a device for detecting recirculation. The device according to the invention and the method according to the invention are based on a targeted haemodilution by administering a bolus of a substitution fluid (substituate), which leads to a change in the pressure conditions in the venous and arterial branches (6, 7) of the extracorporeal circuit as a result of a change in the viscosity of the fluid flowing in the extracorporeal blood circuit (5A). Recirculation is determined by detecting the pressure change in the extracorporeal circuit. The device for detecting recirculation has a control unit (17), which cooperates with the blood conveying device (8) in the blood treatment device and with the substituate conveying device (16) in the blood treatment device. The control unit (17) provides an operating mode for detecting recirculation, in which the blood flow rate is reduced during administration of a substituate bolus. With the simultaneous bolus administration of substituate and reduction of the blood flow rate, the composition of the fluid flowing through the extracorporeal circuit is optimized for detecting recirculation, and therefore larger pressure changes in the venous and arterial branches of the extracorporeal circuit are produced. The overall sensitivity and reliability of the measuring method is thereby improved.