Multi-stable Compliant-Mechanism-based Mattress for Bedsore Prevention - Abstract
Pressure ulcers or decubitus ulcers, more commonly known as bedsores are a huge problem
affecting 2.5 million patients every year in the US and causes 60,000 deaths every year.
Pressures exceeding 32 mm of Hg in the bony prominences in the back of the patient body lead
to bedsores. Despite the existing low air loss mattresses, alternating pressure mattresses and the
state-of-the-art air fluidized beds, bedsores prevail, and its prevention remains a huge healthcare
challenge. Current hospital protocol is to turn patient every two hours. This is very disturbing and
cause of pain to a resting patient who is dealing with other co-existing health conditions besides
bedsores. Caregivers and nurses must turn heavy patients around, which sometimes lead to
hurting their backs in the process. When not performed adequately and frequently (every 2 hours)
as required, it is considered as negligence of care and causes litigation against nursing homes
and hospitals causing huge financial losses to them. We propose a compliant-mechanism-
based mattress that will obsolete the current clinical protocol of nurses and caregivers
having to turn the patient every two hours. It will operate with minimal power, make small
clicking noise when changing from one stable state to another using amount of force required to
open a desk drawer. This switching of states can be further automated and can include a simple
counter for documented evidence of alternating pressure to support against litigation of negligent
care. In specific aim 1, machine learning using trained neural network will determine the functional
requirements of the mattress (e.g., optimal amplitude and pitch for the undulation of the pressure
points) by conducting a cohort pressure profile study that involves a bed that intentionally applies
pressure on resting bodies. In specific aim 2, ideal topology with pitch and amplitude of
undulations discovered in aim 1 will be developed using FACT and optimized using BLOT to
create a prototype bi-stable compliant-mechanism-based mattress as a new approach for shifting
pressure points on a patient’s body. FACT is advanced technique using freedom and
constraint topologies for topology synthesis of the mattress and BLOT provides boundary
layer optimization of the topology. Proposed mattress is innovative, disruptive, affordable,
lightweight, does not use noisy air pumps, has no leakage issues and will eliminate the
scourge of bedsores in the existing immobile and aging population.
