Body-Mounted Sensors for Patient Torso Angle Estimation
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Solution Overview
Problem
Current person support apparatuses, such as hospital beds, struggle to accurately monitor patient position and movement, often leading to false alarms and incomplete assessments due to reliance on bed-mounted sensors that cannot distinguish between patient actions like sitting up or laying down, and may not detect independent rolling or sliding, which can result in inadequate care responses.
Innovation Solution
A system that uses body-mounted sensors remotely coupled to the person support apparatus, providing detailed information on the patient's position relative to gravity and bed status, allowing for precise monitoring of torso angle, movement, and activity level, and enabling the control module to adjust therapy features or alert caregivers as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bed-mounted sensors are used to monitor patient position, then the device complexity is reduced, but the measurement precision and reliability of patient position detection deteriorate
Solution Approach 1:
The patent introduces body-mounted sensors as an intermediary device between the patient and the monitoring system. These sensors directly attach to the patient's body (torso, hips, shoulders) to measure actual body orientation and position relative to gravity, rather than inferring position from bed angle. This intermediary approach resolves the contradiction by providing direct, accurate measurement without requiring complex bed-mounted sensor arrays.
Solution Approach 2:
The patent replaces the mechanical inference system (where bed-mounted sensors measure bed angle and calculate patient position) with a direct sensing system (where body-mounted sensors directly measure patient orientation). This substitution eliminates the need for complex mechanical relationships and calculations, achieving both simplicity and accuracy.
2Ease of operation
If bed-mounted sensors are used to monitor patient position, then the ease of operation is improved, but the reliability of detecting independent patient movements deteriorates
Solution Approach 1:
The patent segments the monitoring system into multiple independent body-mounted sensors placed at different anatomical locations (torso, hips, shoulders). Each sensor independently measures local body orientation, and the control module integrates these readings to detect independent movements. This segmentation allows the system to reliably distinguish between patient-initiated movements and passive position changes while maintaining ease of operation through automated processing.
Solution Approach 2:
The patent implements feedback by continuously comparing sensor readings from multiple body locations to detect discrepancies that indicate independent patient movements. When the relative orientation between sensors changes beyond expected ranges, the system generates alerts. This feedback mechanism enhances reliability while the automated nature of the process maintains ease of operation.
3Measurement precision
If body-mounted sensors are used to monitor patient position, then the measurement precision of patient position and movement is improved, but the device complexity increases
Solution Approach 1:
The patent employs universal body-mounted sensor units that can be placed at multiple body locations and serve multiple functions: measuring torso angle relative to horizontal, detecting lateral rotation, monitoring longitudinal movement, and assessing activity level. Each sensor unit is multi-functional, using the same basic sensor technology (accelerometers, gyroscopes) to provide comprehensive position and movement data, thereby managing complexity through standardization.
4Reliability
If body-mounted sensors are used to monitor patient position, then the reliability of patient position assessment is improved, but the loss of information increases due to additional data processing requirements
Solution Approach 1:
The patent extracts and focuses on specific, clinically relevant parameters from the sensor data: torso angle relative to horizontal, lateral rotation angle, longitudinal position along the bed, and activity level. Rather than processing all possible sensor outputs, the system extracts only the essential information needed for reliable patient position assessment and safety monitoring, reducing data processing overhead while maintaining high reliability.
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 approach provides a more accurate and comprehensive monitoring of patient position and movement, reducing false alarms and enabling timely interventions, thus improving patient safety and care by offering a holistic evaluation of the patient's body position and activity.
Implementation Method 1
body position signals indicate a position of the person relative to gravity
Data Source
AI summary
A person support apparatus supports a person in a laying-down or a seated position. One or more body-mounted sensors detect changes in the position of the person relative to a reference. A control system receives output from the body-mounted sensor or sensors through a remote coupling. The control system uses patient position information obtained from the body-mounted sensors to determine whether the person has experienced a change-in-position and/or a change-in-activity event. Alternatively or in addition, the position of the person situated on a person support apparatus is detected using one or more sensors that are not body-mounted, but rather are coupled to the person support apparatus or to another component of a patient support system. The patient position information is used to estimate the patient's torso angle. The estimated torso angle is used to assess the patient's condition.