Single-Needle Hemodialysis Device with Oscillating Pump Volume
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Solution Overview
Problem
Conventional single-needle hemodialysis machines have a relatively low clearance performance due to the limited pump volume, which is determined by the elasticity and nominal volume of the blood-side lines, resulting in reduced therapeutic effectiveness and requiring expensive modifications for improved intake volume.
Innovation Solution
Incorporating an oscillating pump and a synchronizer in the dialysate circuit to manage the oscillating volume and line valve switching, allowing for increased pump volume and efficient fluid substitution during the dialysis process without changing the blood-side lines, thus enhancing clearance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional single-needle dialysis is used with elastic blood-side lines, then the setup is simple and quick, but the pump volume is limited to about 100 ml or less, resulting in low clearance performance
Solution Approach 1:
The pump volume is segmented into two independent parts: the blood-side line volume (elastic expansion) and the dialysate-side oscillation volume. By separating these functions, the invention allows the dialysate-side oscillation pump to contribute additional volume without being constrained by the elastic limits of the blood-side lines, thereby increasing total pump volume and clearance performance while maintaining setup simplicity.
Solution Approach 2:
The oscillation pump acts as an intermediary device on the dialysate side that introduces additional volume to the system. This intermediary component enables the pump volume to exceed the limitations imposed by the blood-side line elasticity, improving clearance performance without complicating the blood-side tubing configuration.
2Productivity
If measures are taken to increase suction volume, then clearance performance improves, but the measures are complex and require special suction and return lines, increasing device complexity and costs
Solution Approach 1:
The oscillation pump on the dialysate side serves multiple functions: it provides additional pump volume for clearance performance, maintains fluid balance, and can operate independently of special tubing configurations. This multi-functional approach increases clearance performance without requiring complex special suction and return lines, thereby reducing device complexity.
Solution Approach 2:
The invention changes the parameter of pump volume by introducing the oscillation pump that can vary its stroke volume. This parameter change allows the system to achieve higher pump volumes without altering the basic tubing configuration, avoiding the need for complex special lines while improving clearance performance.
3Productivity
If the pump volume is increased, then therapeutic effectiveness improves, but the pump volume is determined by the elasticity and nominal volume of the blood-side tubing, limiting the improvement
Solution Approach 1:
The pump volume is segmented into blood-side contribution (elastic line expansion) and dialysate-side contribution (oscillation pump stroke volume). This segmentation allows the dialysate-side oscillation pump to independently increase its stroke volume to improve therapeutic effectiveness, without being constrained by the elastic and nominal volume limitations of the blood-side tubing, thereby enhancing pump volume adaptability.
Solution Approach 2:
The oscillation pump serves as an intermediary that decouples the pump volume from the blood-side line properties. By placing the oscillation pump on the dialysate side, the system can achieve higher and more adaptable pump volumes without being limited by the elasticity and nominal volume of the blood-side tubing, thus improving therapeutic effectiveness with greater versatility.
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 significantly improves the blood purification performance of single-needle dialysis by increasing the total pump volume and maintaining a constant fluid balance, allowing for a seamless transition from two-needle to single-needle operation without additional costs or complex line conversions.
Implementation Method 1
a device control system which coordinates the filling and emptying of the oscillating volume and the switching of the line valve
Implementation Method 2
Due to their elasticity, the lines expand beyond their nominal volume during this process. The aspiration phase is terminated by pressure control or time control, and the line valve is opened, initiating the return phase. During the return phase, the blood volume stored under pressure in the lines is forced back into the patient's blood vessel through the vascular access line as the lines elastically contract back to their nominal volume.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a hemodialysis device (10) for performing single-needle hemodialysis treatment, comprising a dialysate circuit (12), a blood circuit (14), and a dialyzer (30) between the dialysate circuit (12) and the blood circuit (14), wherein the dialyzer (30) has a dialysate chamber (32) and a blood chamber (34), wherein the dialysate circuit (12) comprises: a dialysate source (20) from which a dialysis fluid is supplied, a delivery pump (24) between the dialysate source (20) and the dialyzer (30) for delivering the dialysis fluid from the dialysate source (20) to a dialysate chamber (32) of the dialyzer (30), and a waste pump (26) downstream of the dialysate chamber (32) of the dialyzer (30), wherein the dialysate chamber (32) and the waste pump (26) are connected by a The drainage lines (22) are fluidically connected to each other, with the blood circuit (14) having: a single vessel connection line (48), to which a line branch (47) is connected,a suction line (40) leads to an inlet of the dialyzer blood chamber (34) and a return line (50) leads to an outlet of the dialyzer blood chamber (34), a blood pump (44) is located along the suction line (40), and a line valve (51) is located along the return line (50), wherein a separate oscillation volume (60') branching off from the drain line (22) is arranged in the dialysate circuit (12) and fluidically between the feed pump (24) and the waste pump (26), and wherein a device control (70) is provided which coordinates the switching of the line valve (51) and the oscillation of the oscillation volume (60').