Medical Sensor Stiffening Member Reduces Motion Artifacts

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Solution Overview

Problem

Pulse oximetry sensors are prone to motion artifacts due to variations in the optical distance between the emitter and detector caused by mechanical changes during use, leading to measurement errors in dynamic environments like emergency rooms and intensive care settings.

Innovation Solution

The sensors incorporate a stiffening member or mechanism to maintain a fixed optical distance between the emitter and detector, reducing the impact of mechanical deformations and movements, thereby minimizing motion artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sensor is made flexible to conform to patient tissue, then ease of operation and patient comfort are improved, but the optical distance between emitter and detector varies during movement, causing motion artifacts and reducing measurement precision

Engineering Contradiction:

Improveease of conformation to patientVSAvoidmeasurement precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The sensor is divided into flexible portions (sensor body, adhesive layer) that conform to patient tissue and a rigid portion (stiffening member) that maintains fixed optical distance between emitter and detector. This segmentation allows different parts of the sensor to fulfill different functions: the flexible parts provide ease of conformation while the rigid part ensures measurement precision by preventing mechanical deformation during movement.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the sensor components are held rigidly together to maintain fixed optical distance, then measurement precision is improved, but the sensor becomes less adaptable to different patient anatomies and reduces ease of conformation

Engineering Contradiction:

Improvemeasurement precisionVSAvoidadaptability to patient anatomy

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The sensor structure is segmented into rigid and flexible portions. The rigid portion (stiffening member) containing the emitter and detector maintains fixed optical distance for precise measurements, while the flexible portions (sensor body, adhesive layer) allow the sensor to conform to various patient anatomies. This segmentation resolves the contradiction by assigning different mechanical properties to different functional zones of the sensor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the sensor have different mechanical qualities: the stiffening member is rigid to maintain optical distance, while the sensor body and adhesive layer are flexible to conform to tissue. This local differentiation of material properties allows the sensor to simultaneously achieve measurement precision and adaptability to different patient anatomies.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the sensor is made disposable for ease of sterilization and hygiene, then ease of operation and patient safety are improved, but the optical components may be more susceptible to damage and reduce device reliability

Engineering Contradiction:

Improveease of sterilizationVSAvoiddevice reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The rigid portion with optical components is designed to provide mechanical protection and structural stability throughout the sensor's intended use period. This pre-engineered structural support cushions and protects the vulnerable optical components from damage during normal use, ensuring reliable operation until the sensor is removed for disposal after a single use, thus maintaining both ease of sterilization and device reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 design significantly reduces the occurrence of motion artifacts, leading to more accurate and reliable pulse oximetry measurements by stabilizing the optical path, even in environments with patient movement.

Implementation Method 1

a non-invasive sensor that transmits electromagnetic radiation, such as light, through a patient's tissue and that photoelectrically detects the absorption and scattering of the transmitted light

Methodology Applied

Scientific EffectLight transmission: Light

Implementation Method 2

photoelectrically detects the absorption and scattering of the transmitted light in such tissue

Methodology Applied

Scientific EffectPhotoelectric detection: Photoelectric Effect

Implementation Method 3

The sensor body is adapted to hold the emitter and detector at a substantially fixed optical distance relative to one another when the sensor is applied to a patient

Methodology Applied

Scientific EffectMechanical stabilization:

Data Source

PatentUS8965473B2Medical sensor for reducing motion artifacts and technique for using the same

Publication Date: 2015.02.24 COVIDIEN LP

AI summary

A sensor for pulse oximetry or other applications utilizing spectrophotometry may be adapted to reduce motion artifacts by fixing the optical distance between an emitter and detector. A flexible sensor is provided with a stiffening member to hold the emitter and detector of the sensor in a relatively fixed position when applied to a patient. Further, an annular or partially annular sensor is adapted to hold an emitter and detector of the sensor in a relatively fixed position when applied to a patient. A clip-style sensor is provided with a spacer that controls the distance between the emitter and detector.