Single-Needle Blood Treatment Pump Segmentation
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Solution Overview
Problem
Conventional extracorporeal blood treatment devices for single-needle operation are unable to effectively manage small blood flows, as they require a minimum rotational speed for smooth operation, resulting in a blood flow that is too high for patients with low body weight, such as small children and infants.
Innovation Solution
The device operates both blood pumps simultaneously in the arterial and venous phases, allowing for different pumping rates, where the delivery rate into the blood collection means is higher than the delivery rate from it, enabling efficient blood treatment with low blood flow rates by utilizing high-capacity pumps and small dialyzers, and allowing for recirculation of blood through the dialyzer or filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional blood pumps are used to maintain smooth operation with minimum rotational speed, then the pump operates reliably, but the blood flow rate becomes too high for patients with low body weight
Solution Approach 1:
The patent divides the blood pumping function into two separate pumps: a first blood pump for drawing blood from the patient and a second blood pump for returning blood to the patient. This segmentation allows each pump to operate independently at optimized speeds, enabling the system to achieve low effective blood flow rates (difference between pump rates) while maintaining high individual pump speeds for reliability
Solution Approach 2:
The patent changes the operational parameters by allowing the two blood pumps to rotate in opposite directions and at different speeds. The first pump rotates in one direction to draw blood, while the second pump rotates in the opposite direction to return blood. By controlling the speed difference between these two pumps, the system achieves low effective blood flow rates suitable for small children while maintaining high individual pump speeds for smooth operation
2Device complexity
If a single blood pump is used in single-needle operation, then the device structure is simplified, but the blood flow management becomes problematic for low body weight patients
Solution Approach 1:
The patent segments the blood flow management into two independent pumping actions: one for arterial phase (drawing blood) and one for venous phase (returning blood). This segmentation enables precise control of blood flow rates in each phase, allowing the system to achieve low effective blood flow rates while maintaining adequate individual pump speeds for reliable operation
Solution Approach 2:
The patent implements periodic action by alternating the operation of two blood pumps in a cyclic manner. The first pump operates during the arterial phase to draw blood from the patient, while the second pump operates during the venous phase to return blood. This periodic operation allows each pump to run at high speeds for smooth operation while the net blood flow remains low due to the alternating nature of their operation
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
This approach allows for effective blood treatment with small blood flows, enabling the use of conventional pumps and small dialyzers, and ensures efficient fluid management, even in patients with low body weight, by maintaining a high flow rate in the extracorporeal circuit while keeping the flow to and from the patient low.
Implementation Method 1
a first means (11) for conveying blood with a first delivery rate (Qba, Qbv) into the blood collecting container (10) during the arterial and venous phase
Implementation Method 2
a second means (12) for conveying blood from the blood collecting container (10) with a second delivery rate (QSNa, QSNv) during the arterial and venous phase
Implementation Method 3
a blood treatment unit (1) through which a patient's blood flows
Implementation Method 4
The blood treatment unit is also generally intended for single use
Data Source
AI summary
The invention relates to a device for the extracorporal blood treatment in a single-needle operating mode, comprising means (11) for delivering blood into, and means (12) for delivering blood out of means (10) for collecting blood, and a controller (13) for setting the respective delivery rates of the means (11, 12) for the delivery of blood. The operating mode of the means (11, 12) for delivering blood is continually switched between an arterial and a venous phase by the controller, wherein during the arterial phase the delivery rate Qb of the means (11) for delivering blood is greater than the delivery rate Qsn of the means (12) for delivering blood such that blood may be withdrawn from the patient during the arterial phase, and during the venous phase the delivery rate Qb is smaller than the delivery rate Qsn such that blood may be administered to the patient during the venous phase.