Wearable Sensor Fusion for Patient Fall and Position Detection

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Solution Overview

Problem

Patients confined to bed for extended periods, especially those who are unconscious or sedated, are at risk of developing pressure ulcers due to sustained pressure and shear forces, which existing turning protocols fail to account for spontaneous position changes between scheduled repositioning intervals.

Innovation Solution

A wearable wireless sensor system that monitors a patient's position and orientation, including accelerometers, gyroscopes, and magnetometers, to detect actual changes in orientation and alert caregivers when deviations from prescribed turning protocols occur, thereby reducing the risk of pressure ulcers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional turning protocols are used to prevent pressure ulcers, then pressure ulcer prevention is improved, but the system cannot detect spontaneous position changes between scheduled repositioning intervals

Engineering Contradiction:
Improvepressure ulcer preventionVSAvoidspontaneous position changes
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent implements continuous monitoring using accelerometers, gyroscopes, and magnetometers to provide real-time feedback on patient position and orientation. This feedback loop enables the system to detect spontaneous position changes between scheduled repositioning intervals and alert caregivers, ensuring that pressure ulcer prevention protocols are consistently followed without missing any position changes.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If continuous monitoring is implemented to track patient position, then detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveposition and orientation detectionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing technologies (accelerometers for linear acceleration, gyroscopes for angular velocity, and magnetometers for magnetic field orientation) into a single integrated sensor unit. This merging approach enables comprehensive three-dimensional position and orientation tracking while consolidating hardware complexity into one cohesive device rather than separate systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor system is designed to perform multiple functions: detecting position, orientation, spontaneous position changes, and monitoring compliance with turning protocols. By making the system universal and multi-functional, the patent reduces the need for separate monitoring devices and achieves comprehensive patient monitoring with a single integrated solution.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple sensors are used to detect position changes, then measurement accuracy is improved, but cost and device complexity increase

Engineering Contradiction:
Improveposition change detection accuracyVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs dynamic sensing capabilities where accelerometers detect linear acceleration, gyroscopes measure angular velocity, and magnetometers determine magnetic field orientation. These dynamic measurements are processed together to calculate three-dimensional position and orientation changes, enabling accurate detection of patient movements while utilizing the complementary strengths of each sensor type.

Inventive Principle:
Principle #15Dynamics

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 system effectively tracks patient repositioning and alerts caregivers to deviations, enhancing compliance with turning protocols and reducing the incidence of pressure ulcers.

Implementation Method 1

The sensor can include an accelerometer configured to measure linear acceleration of the patient

Methodology Applied
Scientific EffectAcceleration: Accelerometer

Implementation Method 2

The sensor can include a gyroscope configured to measure angular velocity of the patient

Methodology Applied
Scientific EffectAngular velocity: Gyroscope

Implementation Method 3

The sensor can include a magnetometer configured to measure strength of a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetometer

Data Source

PatentEP3525661B1Systems and methods for patient fall detection
Publication Date: 2025.07.23 MASIMO CORP
  • EP3525661B1 patent drawingFigure 1A
  • EP3525661B1 patent drawingFigure 1B~1C
  • EP3525661B1 patent drawingFigure 1D

AI summary

A patient monitoring system to help manage a patient that is at risk of falling is disclosed. The system includes a patient-worn wireless sensor that can be affixed to the patient's back that senses the patient's motion and wirelessly transmits information indicative of the sensed motion to a patient monitor. The patient monitor receives, stores, and processes the transmitted information to determine whether the patient has fallen or is about to fall. Upon such detection, the system can notify the patient's caretakers that the patient has fallen or is about to fall and therefore, is in need of immediate attention.