Dual-Needle Pericardial Access for Controlled Space Entry
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Solution Overview
Problem
Accessing the pericardial space through the pericardium is challenging due to its narrowness, which can lead to overshooting and inadvertent entry into adjacent heart chambers, and the use of standard needles can cause excessive bleeding, especially in patients with little fluid, or result in complications like pericardial tamponade.
Innovation Solution
A medical access system comprising an outer and inner needle assembly, where the inner needle shaft has a narrower distal portion and a wider portion with a transition segment, allowing controlled advancement to target the pericardial space, and includes features like radiopaque markers and pressure sensors for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard sized needles are used to access the pericardial space, then the needle can penetrate the pericardium, but excessive bleeding occurs upon withdrawal and complications like pericardial tamponade result
Solution Approach 1:
The needle is divided into two separate assemblies: an outer needle assembly with a larger diameter for penetrating the pericardium, and an inner needle assembly with a smaller diameter for accessing the pericardial space. This segmentation allows each needle to be optimized for its specific function, preventing excessive bleeding while maintaining penetration capability.
Solution Approach 2:
The inner needle assembly is nested within the outer needle assembly, with the inner needle shaft positioned inside the outer needle shaft. The inner needle can be advanced independently through the pericardial space while the outer needle remains in place, allowing controlled access without causing excessive bleeding.
2Force
If force is applied to puncture the pericardium, then access to the pericardial space is achieved, but the narrowness of the space causes overshooting and inadvertent entry into adjacent heart chambers
Solution Approach 1:
The dual-needle design separates the penetration function (outer needle) from the access function (inner needle). The outer needle handles the forceful puncture through the pericardium, while the inner needle provides precise control for accessing the narrow pericardial space without causing overshooting.
Solution Approach 2:
The outer needle assembly acts as an intermediary tool during the procedure. It is used to establish initial access and guide the inner needle into the pericardial space, providing a stable platform for precise positioning while avoiding direct force application that would cause overshooting.
3Adaptability or versatility
If a narrow pericardial space is accessed, then fluid can be drained or medication administered, but the narrowness makes targeting difficult and increases the risk of complications
Solution Approach 1:
The needle system is segmented into an outer needle for establishing access and an inner needle for precise targeting within the pericardial space. This allows the operator to first establish a stable outer needle position, then independently advance the inner needle to the precise target location, making the narrow space accessible while improving ease of operation.
Solution Approach 2:
The outer needle is positioned and secured first as a preliminary action, creating a stable access point. Only after this preliminary positioning is established does the operator advance the inner needle into the pericardial space, making the targeting process easier and more controlled despite the narrow dimensions.
Data Source
AI summary
A medical access system can comprise an inner needle assembly including an inner needle shaft configured to be slidably disposed at least partially within a delivery lumen of an outer needle assembly, the inner needle shaft comprising a narrower distal portion and a wider portion proximal of the narrower distal portion, and a transition segment between the narrower distal portion and the wider portion. A first delivery lumen within the inner needle shaft can extend from a proximal end of the inner needle shaft to a distal end opening at a distal end of the narrower distal portion, and a second delivery lumen within the inner needle shaft can extend from the proximal end to a distal opening associated with the transition segment.