Physician-Inspired Medical Device Solutions
With the goal of engaging graduate students and accelerating ideas
into prototypes, teams of MIT graduate students in Electrical Engineering and
Mechanical Engineering spend a semester collaborating with clinicians in
CIMIT-affiliated hospitals to develop innovative medical devices. Clinicians
(physicians, nurses, and scientists) present clinical problems and initial
ideas on how they might be solved. Students form teams to work with the
clinicians to turn these ideas into reality. The goal is for the students to
deliver a working prototype and a journal-quality article in one semester. The
course has been a great opportunity for clinicians to test out new ideas and to
stimulate new collaborations. For example, Robopsy, a robotic device to assist
radiologists performing tumor biopsies was invented by an MIT team led by Rajiv
Gupta, MD, in 2004. The team has been awarded the 2007 MIT $100K prize, the
world's leading entrepreneurship competition. Join us March 4 and 11 to hear
from the teams of 2007.
Moderator: Hong Ma, PhD, Postdoctoral Associate, Department of
Mechanical Engineering, Massachusetts Institute of Technology, and Instructor,
2.996/6.971 Biomedical Devices Design Course,
Physician/Student Teams:
GRIT Chair Alarm
Lauren Kattany, RN, Clinical Nurse Specialist,
Students: Heather Knight, Jae-Kyu Lee
Falls are a
major problem in hospitals around the world, for they hurt patients and can
cause costly injuries. Nurses are
usually the people primarily responsible for preventing falls, but they are
often asked to tend many patients while simultaneously performing a number of
other tasks. Although getting out of bed
helps a patient avoid many conditions such as deep vein thrombosis, skin
breakdown, and functional decline, nurses are sometimes forced to limit a
patient’s mobility because they feel unable to ensure that patient’s
safety. Current devices used to prevent
patients from getting up and attempting to walk around include bed alarms,
clips, and restraints. Restraints are
undesirable because they are uncomfortable and frightening for patients and
because they can make a fall very dangerous.
Bed alarms and clips have other drawbacks. They do not alert individual caregivers, they
are only set off after a patient has gotten up, and they are prone to false alarms. A new device is needed that will alert
individual nurses when a patient begins to get up, not after the fact.
To solve this problem, graduate
students from MIT created a chair alarm based on gesture recognition
interactive technology (GRIT). Their
device is a pad that can be placed on existing chairs and that can communicate
wirelessly with the hospital’s existing WiFi network. It consists of pressure sensors on the seat
and arms of the chair, and proximity sensors on the back of the chair. A microchip takes these inputs and uses an
algorithm to figure out what the patient is doing (whether he or she leaning
forward to get up, whether he or she is fidgeting, etc.). When the device recognizes a dangerous
gesture, such as leaning forward while pressing on the arms of the chair, it
wirelessly alerts the nurse’s station, and it also communicates with the
patient via a speaker, asking him or her to sit back down. Because it can
differentiate amongst a number of behaviors, the device can respond in a tiered
fashion and can give instructions to suit the situation. Unlike previous chair alarms, the GRIT alarm
system recognizes behaviors that occur early in the process of getting up. Thus, it is can preemptively alert a nurse
while simultaneously asking the patient to remain seated. The GRIT chair alarm is a nuanced tool that
will help nurses prevent falls and that may be applicable to other situations
in which patient monitoring is required.
SmartPad – A Wireless,
Stickerless EKG System
Rob Sheridan, MD, Chief, Burn Surgery Service, Shriners Hospital for
Children; Co-Director, Sumner Redstone Adult Burn Unit, Massachusetts General
Hospital, rsheridan@partners.org
Students: Fred Chen, Pei-Lan Hsu, Brad Stronger, Henry Wu, Hong Ma
In an
ambulance or in an operating room, it is necessary to monitor a patient’s vital
signs. In order to monitor a patient’s
electrocardiogram (EKG), adhesives pads attached to electrodes are applied to
the patient’s skin, and the electrodes are connected to wires that run to
display monitors. The adhesive pads and
wires may become disconnected or interfere with the medical team’s access to
the patient.
In order to
eliminate the need for adhesives and wires and to improve access to the patient
during transport or surgery, the Smart Pad is being developed. The Smart Pad is a thin foam pad on which the
patient lies. An array of approximately
twenty sensors is incorporated into the pad.
A computer software program scans the array of sensors, selects the best
set for the patient’s size and position, and then uses information from these
sensors to produce an EKG waveform. The
Smart Pad is unable to display a 12-lead EKG, but its display of the patient’s
EKG waveform is adequate to monitor the patient during transport or
surgery. The Smart Pad eliminates the
use of adhesive pads, which can detach and can be difficult to place in burn
patients, and the use of wires that can interfere with patient access.
Hand-held Endotracheal
Tube Placement Sensor
Rob Sheridan, MD, Chief, Burn Surgery Service, Shriners Hospital for
Children; Co-Director, Sumner Redstone Adult Burn Unit, Massachusetts General
Hospital, rsheridan@partners.org
Students: Keith Durand, Byron Hsu, Brandon Pierquet, Warit Wichakool
When a
patient is unable to adequately breathe on his or her own, an endotracheal
tube (ETT) is placed into the patient’s
trachea via the nose or the mouth and is positioned at the bifurcation of the
trachea, just above the carina. Correct
positioning of the tube is essential for adequate ventilation. If the ETT migrates too low or too high,
significant morbidity and mortality can result.
Currently, there is no economical
and convenient way to verify the position of an ETT. Although the outside portion of the tube may
appear to be positioned correctly, the inner tip of the tube may have moved so
that ventilation is not satisfactory, or it may subsequently become dislodged. Periodic X-rays done to assess the placement
of the tube give information for only one point in time as well as being
expensive and exposing the patient to repeated radiation. Graduate students from MIT developed a device
to sense the position of the ETT to confirm initial placement and subsequently
check the position of the tube. A small
magnet is embedded into the ETT itself, and a hand-held placement sensor is
then held over the sternal notch of the intubated patient. This portable sensor measures the magnetic
field underneath the sensing area using a two-dimensional array of Giant
Magnetoresistance (GMR) sensors, localizing the position of the magnet embedded
in the tip of the ETT. The device then
displays a color-coded map indicating the position of the magnet, or it sends
the data wirelessly to a computer. It
provides real-time information regarding the position of the ETT rather than
information at one point in time, as would be given by an X-ray. By confirming initial placement of the tube
and by checking for any migration of the tube, the device will hopefully
decrease the need for emergency tube replacement. In the future, the device could be adapted to
continuously monitor ETT placement and to automatically notify the medical team
if a problem with placement were detected.