Johns Hopkins undergraduates have designed and built a device to enable critically ill intensive care unit patients to leave their beds and walk while remaining tethered to essential life-support equipment. The invention allows doctors to better understand whether carefully supervised rehabilitation, as opposed to continuous sedation and bed rest, can improve the recovery of intensive care patients.
Some clinicians believe that allowing ICU 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 this new ICU rehabilitation program, a physician at Johns Hopkins Hospital 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 physician Dale Needham, an assistant professor in the Division of Pulmonary and Critical Care Medicine at the Johns Hopkins 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, 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," said Lerman, 22, from Delray Beach, Fla. "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 staff 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 in the Medical ICU at Johns Hopkins. 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 a recent competition for Johns Hopkins 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 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.
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