Patient Exit Detection Control Using Load-Cell Position Sensing
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Solution Overview
Problem
Existing patient support apparatuses, such as hospital beds and stretchers, allow patients to disarm exit detection systems, enabling them to exit undetected, which compromises caregiver notification and patient safety.
Innovation Solution
Incorporating a controller that uses load cells to compute a patient's center of gravity and detect attempts to disarm the exit detection system, preventing disarming by disabling the control when the patient is within a defined distance from the control interface, thereby maintaining the alert state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the exit detection system allows patient control for disarming, then the patient can exit without unnecessary alerts, but the patient can disarm the system and exit undetected compromising safety
Solution Approach 1:
The control interface is configured with location-aware functionality that enables disarming only when the patient is in specific safe zones (e.g., near the head of the bed). When the patient moves to other locations (e.g., near the edge or foot of the bed), the disarming capability is automatically restricted. This spatial differentiation of control permissions resolves the contradiction by allowing patient autonomy in safe contexts while maintaining system reliability in risky contexts.
2Reliability
If the exit detection system monitors patient position continuously, then patient safety is improved through accurate exit detection, but system complexity increases
Solution Approach 1:
The support surface is divided into multiple sensor zones with different monitoring functions. Load cells are positioned at specific locations to detect patient presence and position. The controller segments the monitoring task by evaluating sensor data from different zones independently and applying different disarming permissions based on which zone the patient occupies. This segmentation reduces overall system complexity while maintaining detection accuracy.
Solution Approach 2:
The system automatically determines patient position and disarming eligibility without requiring manual intervention or complex external monitoring. The load cells and controller work together to self-evaluate patient location and automatically enable or disable disarming functionality based on pre-programmed safety criteria. This self-service approach simplifies the control architecture while maintaining reliable exit detection.
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
Prevents patients from disarming the exit detection system, ensuring caregivers are notified of patient exits, reducing the risk of falls and injuries by maintaining the alert state.
Implementation Method 1
the exit detection sensors comprise a plurality of load cells configured to detect downward forces exerted on the support surface by the patient
Data Source
AI summary
A patient support apparatus, such as abed, cot, stretcher, or the like, includes a frame, support surface, exit detection system, and control. The exit detection system includes multiple sensors and a controller configured to issue an exit alert when the patient exits from the support surface. The control is configured to disarm the exit detection system, and the controller is further configured to use outputs from the exit detection sensors to detect when the patient on the support surface may be making an attempt to disarm the exit detection system, and to prevent the patient from disarming the exit detection system during the attempt. The sensors may comprise load cells. In some embodiments, the control is positioned at the foot end of the patient support apparatus, while in other embodiments, the control may be positioned along a siderail of the patient support apparatus.