Catheter Tip Triangulation via Torso Pad Signals
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Solution Overview
Problem
Current methods for guiding the placement of peripherally inserted central catheters (PICCs) within a patient's vasculature are inaccurate and unreliable, particularly in patients with abnormal cardiac conditions, leading to mechanical complications and the need for chest X-Ray verification, which increases time, expense, and radiation exposure.
Innovation Solution
A system using three or more pads on the patient's torso to generate electrical signals and a stylet with bipolar and unipolar electrodes that triangulates the position of the catheter tip within the vasculature, allowing for precise placement without external imaging, by comparing the stylet's electrical signals with the pad signals to determine the catheter's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ECG P-wave amplitude tracking is used to determine catheter tip location, then the method is simple to implement, but it becomes inaccurate or inapplicable in patients with abnormal cardiac conditions (atrial fibrillation, atrial flutter, severe tachycardia, pacemakers) where P-waves are nonexistent or indiscernible
Solution Approach 1:
The system transitions from tracking P-wave amplitude (temporal parameter) to measuring electrical signal strength from multiple spatial locations (spatial parameters). By using three or more pads arranged in a predetermined pattern and measuring signal strength differences across multiple spatial points, the system determines catheter tip location through triangulation rather than relying on P-wave characteristics, making it applicable to all patients regardless of cardiac rhythm.
Solution Approach 2:
The patent introduces an intermediary measurement approach by using multiple external pads as reference points. Instead of directly observing P-waves from the catheter tip, the system uses pads placed on the patient's torso to capture electrical signals that propagate through the body, creating intermediate measurement points that enable indirect location determination through signal comparison and triangulation.
2Ease of operation
If electromagnetic sensor techniques are used to determine catheter position, then the system can operate without X-rays, but the accuracy is limited because it determines only position relative to an external reference rather than to a specific position within the vascular system
Solution Approach 1:
The system adds spatial dimensionality by using three or more pads arranged in a predetermined pattern across the patient's torso. Instead of a single external electromagnetic reference point, the multiple pads create a spatial reference framework that enables triangulation. By measuring signal strengths from multiple spatial locations and using geometric relationships, the system determines the precise three-dimensional location of the catheter tip relative to the vascular system anatomy.
Solution Approach 2:
The patent replaces the traditional external electromagnetic sensor system with an electrical signal-based triangulation system. Instead of using a single external magnetic or electromagnetic reference, the system uses electrical signals propagated through the body's conductive tissues, measured by multiple pads. The signal processor compares electrical signal strengths from multiple pads to calculate catheter tip position, substituting the mechanical/electromagnetic reference system with an electrical field-based localization approach.
3Productivity
If intravascular ECG sensors are used to track P-wave amplitude changes, then the system can provide real-time feedback, but it cannot indicate the actual position of the catheter tip in the blood vessel, only the distance to the sino-atrial node
Solution Approach 1:
The system introduces external pads as intermediary measurement points that capture electrical signals from multiple locations on the patient's torso. These pads serve as reference points that, when combined with the intravascular electrode measurements, enable triangulation. The signal processor uses the electrical signals from both the intravascular electrode and multiple external pads to calculate the actual spatial position of the catheter tip, not just its distance from the SA node.
Solution Approach 2:
The patent transitions from one-dimensional distance measurement (distance to SA node along the catheter path) to three-dimensional spatial positioning. By incorporating multiple external pads arranged in a predetermined pattern and measuring electrical signal strengths from multiple spatial directions, the system determines the catheter tip's precise x, y, z coordinates within the vascular system, enabling accurate positional indication rather than just radial distance.
4Measurement precision
If chest X-ray verification is used to confirm catheter tip location, then accurate placement can be verified, but it increases procedural time, expense, and radiation exposure
Solution Approach 1:
The patent replaces the mechanical/radiological verification system (chest X-ray) with an electrical field-based triangulation system. Instead of using ionizing radiation to visualize the catheter tip position, the system uses electrical signals propagated through the body's conductive tissues. Multiple pads measure electrical signal strengths, and a signal processor triangulates the catheter tip position in real-time, providing accurate verification without radiation exposure or additional procedural delays.
Solution Approach 2:
The system enables the catheter placement procedure to verify its own position using the patient's body as the measurement medium. The patient's torso and vasculature serve as the reference framework, with electrical signals naturally propagating through the body's conductive tissues. The multiple pads and intravascular electrode work together to self-determine the catheter tip position without requiring external imaging equipment or radiological verification, eliminating the need for separate X-ray verification steps.
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 method provides accurate and reliable placement of PICCs, reducing mechanical complications and eliminating the need for chest X-Ray verification, thereby decreasing procedural time and radiation exposure while improving precision.
Implementation Method 1
Three or more pads are adhered to the patient's torso in a predetermined pad pattern. Each pad is capable of generating a pad electrical signal having predetermined signal characteristics. A stylet electrode is capable of receiving the pad electrical signals
Implementation Method 2
The signal processor is capable of comparing the stylet electrical signal and at least two pad electrical signals to triangulate a position of the stylet electrode relative to each of the pads and responsively produce a triangulated position
Data Source
AI summary
A system for determining a location of a structure within a patients vasculature includes three or more pads adhered to the patients torso in a predetermined pad pattern. Each pad generates a pad electrical signal. A stylet has longitudinally spaced proximal and distal stylet ends, with at least one stylet electrode located proximate the distal stylet end. The stylet electrode receives the pad electrical signals and responsively generates a stylet electrical signal. A signal processor is operatively coupled for signal exchange with the stylet and to each of the pads via a selective electrical coupling. The signal processor compares the stylet electrical signal and at least two pad electrical signals to triangulate a position of the stylet electrode relative to each of the pads and responsively produce a triangulated position. The triangulated position is indicative of a position of the stylet electrode within the patients vasculature.