Some clinicians believe that allowing critically ill
intensive care patients to get out of bed and
walk could avert some of the muscle weakness, bedsores and
depression that typically develop when
these patients are kept heavily sedated and confined to
bed. Because such patients usually must
remain connected to an artificial breathing machine, heart
monitors and intravenous lines with
essential medications, a simple walk down the hall can
require four staff members to accompany the
patient.
To reduce this staffing demand and improve The Johns
Hopkins Hospital's new ICU
rehabilitation program, a physician last year asked
students in a biomedical
engineering design team
course to devise a mobility aid for ICU patients.
Over two semesters, the students, supervised by
faculty members and graduate students and
advised by hospital staff, produced a device called the ICU
MOVER Aid. This device has two
components: a novel mobility aid that combines the
rehabilitative features of a walker and the safety
features of a wheelchair, and a separate wheeled tower to
which important life-support equipment can
be attached.
"The finished product is truly outstanding," said Dale
Needham, an assistant professor in the
Division of Pulmonary and Critical Care Medicine at the
School of Medicine. "The most recent version
of the MOVER is far beyond a rough prototype. The students
exceeded everyone's expectations in
designing a device that we could routinely use in the
Medical ICU."
To help him improve the new Medical ICU rehabilitation
program at Johns Hopkins, Needham
had challenged the students to produce a device that would
meet three key criteria. First, it had to
provide physical support for the patient during walking.
Second, it had to safely house all necessary
monitoring and therapeutic equipment for critically ill
patients. Finally, it needed a safety backup
system for patients who must immediately sit down because
of fatigue or a sudden change in their
medical condition.
"We ended up building three versions," said Joshua
Lerman, then a senior biomedical engineering
student, who served as team leader. "First, we used PVC
pipes to work on the basic design. Then, we
made an aluminum version. We made the final prototype
mostly of steel. All through the process we
got feedback from the hospital's ICU staff, who told us
what we needed to change to make it better
suit patients' needs. All of the staff involved in the ICU
rehabilitation program were very happy with
the final version."
This final version features a walker-type framework,
similar to devices that some frail or
elderly people use to get around. Immediately behind the
patient, however, a fabric seat is attached
to the frame so that a tired patient can sit down. The seat
can also "catch" a patient who abruptly
collapses because of a medical problem. "We made the seat
out of ballistic nylon because we didn't
want it to rip," Lerman said. "It's durable, and it's easy
to clean for infection-control purposes."
As a separate component, the prototype features a
tower designed to accommodate two oxygen
tanks and three medical devices: a cardiac monitor,
intravenous infusion pumps to provide medications
and a ventilator to support breathing. Despite all of the
equipment attached to it, the MOVER
prototype was small enough to maneuver through the Medical
ICU's narrow hallways, although using it
in the ICU patient rooms, which are particularly small,
proved to be more challenging. In terms of
improved efficiency, the inventors said, the MOVER requires
only two hospital staff members to
accompany the walking patient, compared with four under the
earlier system.
Needham, the project's faculty sponsor, said, "We've
tried this device on one MICU patient so
far, and we are certainly keen to continue using it as part
of our physical medicine and rehabilitation
program. The MOVER worked as well with the real patient as
it did when we tested it with the
biomedical engineering students serving as simulated
patients."
At an end-of-semester competition for biomedical
engineering design projects, the MOVER's
team took second-place honors. The student inventors and
their faculty mentors have obtained a
provisional patent for the device and are exploring
commercialization opportunities. Needham said
that much will depend on how quickly other hospitals adopt
new therapies in the ICU setting to
improve patient recovery. "With the increasing interest in
early mobility for ICU patients and the
emerging scientific evidence supporting the benefit of this
approach," he said, "I think there is a
strong commercial future for the MOVER device."
In addition to Lerman, the undergraduates who worked
on this project were Ravy Vajravelu,
Derrick Kuan, Jeremy Elser, Erica Jantho, Jinjie Chen,
Hanlin Wan and Swarnali Sengupta. The design
course is taught by Robert Allen, an associate research
professor and senior lecturer in the
Department of Biomedical Engineering.