Transatrial Catheter Thermal Shadow Elimination

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Solution Overview

Problem

Existing intravascular temperature control systems face challenges in accurately measuring patient core temperature and maximizing cooling rates due to the 'thermal shadow' effect caused by the catheter, which prolongs cooling processes and is limited by size constraints when placed in veins.

Innovation Solution

A transatrial intravascular temperature management catheter with separate heat exchange segments in the inferior and superior vena cava, a connecting segment in the right atrium, and a temperature sensor upstream of the heat exchange segments to minimize contact with the heart and provide accurate core temperature feedback, allowing for efficient temperature regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the temperature sensor is placed on the catheter in the vein to avoid uncomfortable separate probes, then patient comfort is improved, but the thermal shadow effect causes inaccurate temperature measurements

Engineering Contradiction:

Improvepatient comfortVSAvoidcore temperature measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The catheter is divided into multiple segments: a first heat exchange segment in the inferior vena cava, a connecting segment in the right atrium, and a second heat exchange segment in the superior vena cava. The temperature sensor is specifically positioned on the connecting segment that traverses the right atrium, placing it upstream of the thermal shadow zones created by the heat exchange segments in both vena cavae.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connecting segment positioned in the right atrium serves as an intermediary location for the temperature sensor. This segment acts as a thermal buffer zone that is upstream of both heat exchange segments, allowing the sensor to measure core temperature before the blood is influenced by cooling or heating from either vena cava segment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the heat exchange segments are made larger to maximize cooling rate, then cooling efficiency is improved, but the catheter size exceeds vein capacity

Engineering Contradiction:

Improvecooling rateVSAvoidcatheter size

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

Instead of using a single large heat exchange catheter in one vein, the system divides the heat exchange function into two separate segments placed in different veins (inferior and superior vena cava). Each segment can be optimized for heat exchange efficiency while maintaining a size appropriate for its specific venous location, and together they provide the cumulative cooling or heating effect needed.

Inventive Principle:

Principle #1Segmentation

3Temperature

If the connecting segment has larger diameter to facilitate heat exchange, then heat transfer efficiency is improved, but the risk of contacting the right atrium increases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidrisk of atrial contact

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The connecting segment is designed with a smaller diameter specifically for the portion that traverses the right atrium, minimizing the risk of contact with atrial tissue. The heat exchange segments in the vena cavae can have larger diameters optimized for heat transfer, as they are positioned away from the heart. This local differentiation of dimensions optimizes both safety and heat exchange efficiency in different anatomical locations.

Inventive Principle:

Principle #3Local quality

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

Enables accurate core temperature measurement and enhanced cooling rates by positioning the temperature sensor outside the thermal shadow, optimizing heat transfer area without obstructing blood flow, thus improving therapeutic temperature management.

Implementation Method 1

heat exchange segments... through which working fluid is circulated to and from a heat exchange system external to the patient

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

the connecting segment being configured as an elongated tube with a supply and a return lumen for the second heat exchange segment, the connecting segment having a smaller diameter than at least the first heat exchange segment to minimize risk of the connecting segment contacting the right atrium

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2760396B1Transatrial patient temperature control catheter

Publication Date: 2023.01.04 ZOLL CIRCULATION INC

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AI summary

A transatrial intravascular temperature management catheter (10) has a lower heat exchange segment (24) positionable in the inferior vena cava and an upper heat exchange segment (28) positionable in the superior vane cava, with a connecting segment (32) lying between the two and positionable in the right atrium. A temperature sensor (36) on the distal tip of the upper heat exchange segment provides accurate core body temperature signals for feedback purposes since the blood flowing past the sensor has not yet reached the heat exchange segment.