Inflatable mattress and control methods

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Solution Overview

Problem

Healthcare mattresses with inflatable zones face challenges in automatically determining optimal inflation levels to distribute patient weight effectively and ensure comfort, as caregivers struggle to manually set levels that balance pressure distribution and comfort without causing discomfort from excessive sinking.

Innovation Solution

The integration of depth sensors and air pressure sensors with a controller to automatically determine and adjust the inflation levels of inflatable bladders, allowing for individualized support and real-time adjustments based on patient position, movement, and other triggering events, ensuring optimal pressure distribution and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the inflation level of the bladders is increased to distribute patient weight over a greater area, then pressure distribution is improved and bed sore risk is reduced, but patient comfort deteriorates due to excessive sinking into the mattress

Engineering Contradiction:
Improvepressure distributionVSAvoidpatient comfort
Core Design Contradiction:
Stress or pressureVSEase of operation

Solution Approach 1:

The system uses depth sensors to continuously monitor patient immersion depth and provides feedback to the controller. The controller adjusts inflation levels based on this feedback to maintain optimal pressure distribution while preventing excessive sinking, thus resolving the contradiction between pressure distribution and patient comfort

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The mattress transitions from static inflation levels to dynamic adjustment. The inflation level is continuously modified based on real-time depth sensor data, allowing the system to adapt to patient movements and maintain both pressure distribution and comfort dynamically

Inventive Principle:
Principle #15Dynamics

2Stress or pressure

If the inflation level is manually adjusted to balance pressure distribution and comfort, then pressure distribution may be improved, but the complexity of operation increases for caregivers

Engineering Contradiction:
Improvepressure distributionVSAvoidmanual adjustment complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The mattress performs self-adjustment of inflation levels using integrated depth sensors and a controller. The system automatically determines optimal inflation levels without caregiver intervention, eliminating manual adjustment complexity while maintaining pressure distribution benefits

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment process is replaced with an automated sensor-based control system. Depth sensors and a controller substitute for caregiver manual judgment and adjustment, reducing operational complexity while achieving optimal pressure distribution

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the mattress is designed to automatically determine inflation levels using sensors and controllers, then patient comfort and pressure distribution are improved, but device complexity increases

Engineering Contradiction:
Improvepatient comfortVSAvoidautomation system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The depth sensors serve multiple functions: they monitor patient immersion depth for comfort adjustment, detect patient presence, and identify movement events. This multi-functionality reduces the need for separate sensor systems, thereby limiting the increase in device complexity while achieving improved patient comfort

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

4Stress or pressure

If depth sensors and air pressure sensors are integrated to automatically determine inflation levels, then pressure distribution and comfort are optimized, but manufacturing complexity increases

Engineering Contradiction:
Improvepressure distributionVSAvoidmanufacturing complexity
Core Design Contradiction:
Stress or pressureVSEase of manufacture

Solution Approach 1:

The depth sensing and pressure monitoring functions are merged into an integrated control system. The controller processes both depth sensor and air pressure sensor data together to determine inflation levels, simplifying the manufacturing process compared to separate independent systems while achieving optimized pressure distribution

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables mattresses to automatically set and adjust inflation levels, reducing the risk of pressure sores and enhancing patient comfort by dynamically responding to changes in patient position and movement, eliminating the need for manual adjustments and providing tailored support without pre-existing data on patient weight or morphology.

Implementation Method 1

a depth sensor that generates a depth signal indicative of how deeply a patient positioned on the patient support sinks into the inflatable bladder

Methodology Applied
Scientific EffectDepth sensing:

Implementation Method 2

an air pressure sensor that generates an air pressure signal indicative of a level of air pressure inside of the inflatable bladder

Methodology Applied
Scientific EffectAir pressure sensing:

Implementation Method 3

The controller determines a suitable inflation level of the bladder by monitoring a rate of change of the depth signal with respect to the air pressure signal as the air pressure inside the bladder is changed

Methodology Applied
Scientific EffectPressure control:

Data Source

PatentEP2892489B1Inflatable mattress and control methods
Publication Date: 2020.03.11 STRYKER CORP
  • EP2892489B1 patent drawingFigure 1
  • EP2892489B1 patent drawingFigure 2
  • EP2892489B1 patent drawingFigure 3

AI summary

A patient support, such as a mattress, includes a plurality of inflatable bladders. Depth sensors are included in the patient support that measure the degree of penetration of a patient into the mattress. An air pressure sensor is also included that measures the pressure inside at least one bladder. A suitable inflation level of the mattress is determined by monitoring the rate of change of the depth with respect to air pressure as the bladder is either inflated or deflated. By detecting an inflection point in the graphical relationship of the depth and pressure outputs, a suitable inflation point for the bladders is determined that reduced interface pressures experienced by the patient, yet does not overly sink the patient into the mattress to a degree or discomfort. Analyzing the outputs of the depth and pressure sensors can also be used to detect a patient's heart rate and respiration rate.