Identification of involuntary movements in bed using strain gauge sensors detect bending of the elements of the bed

Abstract

Currently, new methods are applied to monitor the involuntary movement and other physiological movements, but physicians do not always require complex equipment or they do not accept the use of devices connected to the patient. We invented a new method which is suitable to monitor the small movements of the patient in a horizontal position on the bed or monitor the movements during short term medical examination. The method is based on the use of sensors configured to detect deformation of construction of the bed. Sensors are implemented into the construction of the bed and detect bending of the elements of the bed. The invented method provides information about the patient's physiological movements, namely it is the breathing rate and heart rate. The method was tested on a set of volunteers / students in order to verify that it works and can be proposed as an application in clinical practice.

A Comparison of Methods Using Strain Gauges to Monitor Physiological Movements on a Hospital Bed

“…A Comparison of Methods to Monitor Physiological Movements on a Hospital Bed Figure 2. Principle of the measurement of bending (A) and torsion (B) [15,16]: 2 -sensors, 4 -mattress base supports, 5 -stand with a column, 7 -beams to transfer the forces, 8 -mattress base.…”

“…Using a range of highly sensitive sensors (e.g., strain gauges [9], accelerometers [10], hydraulic sensors [11], pneumatic sensors [7,12], and optical devices [13]), BCG systems have been integrated into beds [9] and chairs [14]. However, current sensors have one of two disadvantages: either high cost or low sensitivity, [5,15,16]. Currently, the most widely-used sensors are load cells placed in the legs of the bed or directly under the main bed-frame (bearers and/or metal mattress base).…”

“…Strain gauge sensors have been used to eliminate this shortcoming. These sensors are configured to measure the torsional deformation in the element when subjected to a torque or shear force, or to measure the bending deformation in the element when subjected to a bending moment [15,17]. The methods rely on the structure of the bed, which consists of two stands with columns and two-arm brackets and four beams to transfer the gravity forces, see Fig.…”

Robust Ambient Multisensor Signal Fusion Towards Clinical Data Analytics

“…Physiological signals have been captured by sensors in the environment in a variety of ways, but most ambient sensing modalities fall broadly into five main categories: pressure systems, Doppler systems, audiovisual systems, thermal systems, and textile electrodes. Pressure systems are generally placed where an individual would exert pressure when they lie, sit, or stand, and have included many modalities of sensors including pneumatic sensors [22,23,31,32,63,67], piezoelectric polymers [24,30,33,73,78,79], load cells [38,39,41,42,72], force sensitive resistors (FSR) [16][17][18]21,68,71], hydraulic sensors [24,66,80], capacitive sensors [14,69], indentation measurement potentiometers [65], electret films and foils [27,40], optical sensors [28,81], and strain gauges [82].…”

“…However, posture classification before selection may be more complex than is warranted and errors in classification would impact the breathing fusion. Temporal methods analyze the fitness of the signals themselves by examining time-domain characteristics such as the minimum kurtosis [68], maximum signal amplitude [82] or maximum autocorrelation [116]. Autocorrelation makes use of the rhythmicity of the signal, which can also be inferred from the frequency spectrum.…”