Name: Umehani Dalal
Name of Project Advisor: Art Koblasz
Group Name: AK4
Title: Bed Alarm System Detecting Ingress and Egress
Bed Alarm System Detecting Ingress and Egress
Introduction
Patient falls and hospital-acquired infections are big concerns in health care today.
Even though preventing fall and infections seems rather easy, they are among the leading
causes of death in the country. The best way to prevent both falls and infections in
hospitals would be to use a system that detects motion coming into the bed and going out
of the bed (ingress and egress) using a camera, LEDs and sensors. When egress occurs
the system would send an alarm to the attendant on duty to warn them about the patient
leaving their bed and when ingress occurs the system would remind you to wash your
hands. This paper focuses on the benefits of detecting ingress and egress, the current
products available and the technology involved in creating such a system.
Benefits of Detecting Ingress and Egress on Patient Beds
Patients have a high risk of falling due to either being sedated or due to old age.
These falls are often undetected and the patients lie helpless on the floor for hours before
receiving any help. Due to lack of instantaneous help, falls cause major injuries or death.
By being able to detect egress on a patients bed, an alarm can be sent to the nurse on duty
who can make sure that the patient is safe and can help the patient use the restroom if
necessary. This could prevent unnecessary falls and in turn prevent injuries and death.
Infections are another serious issue in hospitals. Due to health care professionals
forgetting to wash their hands while making rounds from one patient to another they
transfer infections. By being able to detect ingress on a patient’s bed, an alarm can
remind people to wash their hands before any interaction with the patient. This will
prevent the transfer of infections and keep the conditions in the hospital sanitary.
Current Bed Alarm Systems
Among applications that help in fall detection one is a bolster system used for
preventing rolling of a person off a mattress and comprises a lateral cushion that is
adapted to be disposed proximate and parallel to an edge of the mattress [1]. Another
product is a protective bed unit comprising a frame including a headboard, one actuator
base, shielding material forming a canopy and leg cover to create a protective chamber
[2]. There are many products that use weight related sensor pads like the Bed-Check
system comprised of a control system and a Sensormat [3].
The problem with applications like the bolster and the frame system is the danger of
entrapment. Entrapment is defined as an event in which a patient is caught, trapped or
entangled in the spaces in or about the bed rail, mattress or hospital bed frame which can
result in serious injury or death. [4]
Currently there are no alarms for ingress in hospital beds that would remind people
to wash their hands before being in contact with the patient.
Underlying Technology used for Ingress/Egress in Hospital Beds
The system required to detect patient ingress/egress without the danger of
entrapment would consist of using a camera and computational vision algorithms using a
computer language like C++. The boundaries of the bed would be defined with the help
of inner and outer rings that would be able to distinguish between ingress and egress
depending on whether movement was detected in the outer or inner ring first.
To complete the ingress and egress project an optical marker based ViconMX
system can be used. The MX system, the most advanced digital optical motion capture
system available in the market today, allows for advanced object tracking in real-time
with no radio frequency (RF) or metallic interference and provides a positional accuracy
better than 1mm and is packaged with 12 near-infrared F20 cameras. [5]
Most hospital beds today are adjustable which makes it hard to define the inner and
outer rings due to movement. Using small LEDs on the corners of the bed would help
define the boundaries even if there was movement. 3mm LEDs are available in the
market in white, blue, green and red. [6] These LEDs would be small enough to not
interfere with the patient but have light that is powerful enough for the camera to detect.
[1] E. Gilchrest, Jr. and G. E. Riehm, “Bolster system and method,” U. S. Patent
7,155,766, 2 Jan., 2007.
[2] J. L. Walling, “Protective bed unit,” U. S. Patent 7,137,881, 21 Nov., 2006.
[3] Bed-Check “Interchangeable Sensormat® Pressure Sensitive Mats,”
bedcheck.com, [Online]. Available:
http://www.bedcheck.com/sensormatwork.html. [Accessed Jan. 22, 2008].
[4] Food and Drug Administration “A Guide for Modifying Bed Systems and Using
Accessories to Reduce the Risk of Entrapment,” U.S. Food and Drug
Administration, [Online]. Available:
http://www.fda.gov/cdrh/beds/modguide.html. [Accessed: Jan. 22, 2008].
[5] Vicon Cameras “Vicon Camera Products,” Vicon Cameras, [Online]. Available:
http://www.vicon.com/products/cameras.html. [Accessed: Jan. 22, 2008].
[6] The LED light “3mm White and Colored LEDs,” The LED Light, [Online].
Available: http://www.theledlight.com/3mmleds.html. [Accessed: Jan. 22, 2008].