Hemodialysis Catheter Stylet With Blocking Dams

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Solution Overview

Problem

Hemodialysis catheters often experience thrombus formations that restrict or block blood flow, requiring inefficient methods to dislodge blockages, especially in catheters with multiple openings where fluid tends to bypass significant blockages due to pressure limitations.

Innovation Solution

A stylet with first and second blocking dams is used within the catheter lumen, creating a zone of pressure between the dams to effectively dislodge blockages from side openings by sealingly engaging with the catheter's inner surface and directing fluid through strategically positioned apertures, reducing the need for precise alignment and fluid volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluid pressure is increased to dislodge thrombus formations, then blockage removal efficacy is improved, but the risk of catheter damage and patient harm increases

Engineering Contradiction:

Improveblockage removal efficacyVSAvoidcatheter damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The catheter is divided into multiple lumens (arterial and venous lumens) that can be independently flushed. This segmentation allows targeted pressure application to specific blocked segments without requiring excessive pressure that could damage the entire catheter or patient vasculature.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A flushing solution acts as an intermediary medium between the pressure source and the thrombus formation. The solution gradually dissolves and dislodges the thrombus through chemical and mechanical action, allowing effective blockage removal at lower pressures that prevent catheter damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If fluid flow rate is increased to clear blockages in multi-opening catheters, then blockage removal speed is improved, but fluid tends to bypass significant blockages through openings with less resistance

Engineering Contradiction:

Improveblockage removal speedVSAvoidblockage clearance completeness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The flushing system targets each lumen and opening segment individually through coordinated flushing of arterial and venous lumens. This ensures that fluid pressure is applied systematically to each potential blockage site rather than allowing bypass through unflushed openings.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flushing procedure begins with preparing the catheter system and positioning the patient before initiating fluid flow. This preliminary preparation ensures proper setup for effective flushing that will clear all openings systematically, preventing bypass of blockages.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If traditional flushing methods are used to dislodge thrombus formations, then the procedure can be performed with simple equipment, but the treatment time is extended and efficacy is limited

Engineering Contradiction:

Improveequipment simplicityVSAvoidtreatment time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The flushing procedure employs continuous fluid flow through the catheter lumens rather than intermittent flushing. This continuous action maintains constant pressure on thrombus formations, significantly reducing treatment time compared to traditional intermittent methods, while still using simple flushing equipment.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system utilizes hydraulic pressure from fluid infusion to dislodge thrombus formations mechanically. This hydraulic approach provides powerful blockage removal capability using simple fluid pressure equipment rather than complex mechanical devices, reducing both equipment complexity and treatment time.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 stylet effectively clears blockages by applying pressure directly to the obstruction, reducing the time and fluid required for the procedure and improving the efficacy of blood flow through the catheter, regardless of distal or side opening blockages.

Implementation Method 1

creating a zone of pressure between the dams to effectively dislodge blockages

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

directing fluid through strategically positioned apertures

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11738170B2Flushing stylet

Publication Date: 2023.08.29 MOZARC MEDICAL US LLC

AI summary

A stylet includes an elongate body defining a passage and at least one aperture in fluid communication with the passage. The stylet also includes a first blocking dam secured to the elongate body proximal to the at least one aperture and a second blocking dam secured to the elongate body distal to the at least one aperture. The stylet is movable within a lumen of a catheter to a position in which the first and second blocking dams are, respectively, proximal and distal to at least one side opening of the catheter and each of the first and second blocking dams is sealingly engaged with an inner surface of the catheter such that fluid introduced into the lumen, from the passage and through the at least one aperture of the stylet, is directed through the at least one side opening of the catheter.