When the birth of a baby does not proceed smoothly,
how much force should a doctor or midwife apply? If a
complicated delivery takes too long, the child could
suffocate; pulling too hard could injure the child.
To address this dilemma, Johns Hopkins biomedical
engineering students have invented an unobtrusive device
— a wireless transmitter sending data from the
doctor's or midwife's arm to a computerthat measures the
amount of force being used while delivering a baby.
This week, four of the students will travel to New
York City, where their device is a finalist in this year's
Inventors Competition, sponsored by the National
Inventors Hall of Fame in Akron, Ohio.
The system already is being tested at The Johns
Hopkins Hospital, where researchers hope it eventually will
help them identify the safest delivery method for a
complicated birth. The inventors believe their device also
could be used as a teaching tool, helping
obstetricians-in-training learn how to assess the amount of
force they use during a routine delivery.
The electromyographic instrument, which measures
electrical impulses in the muscles of the forearm, was
devised and constructed by a team of undergraduates during
a biomedical engineering design team course. Based on this
achievement, the four students who made the most
significant contributions were selected to represent the
team in the competition. The Johns Hopkins device was one
of six undergraduate projects to advance to this stage of
the contest. Following the final judging, the winners will
be announced at an awards dinner on Oct. 23.
The assignment that produced the device came from
Robert Allen, a senior lecturer in the
Department of Biomedical
Engineering. Allen and his obstetrics research
colleagues have been looking for a method of measuring the
force used in a delivery as a way to help determine the
best technique to employ during complicated births.
Previously, inventors have used sensors in gloves or placed
them on the doctor's hands, interfering with the user's
grasp. Allen's students came up with a less intrusive
system, in which three electrodes are attached to the
forearm and connected to a small metal box that rests in
the doctor's pocket. The box collects information from the
electrodes and transmits it to a receiver up to 50 feet
away. The receiver is connected to a laptop computer, which
stores and processes the data.
Three electrodes attached to the
forearm are used to pick up electrical impulses in the
muscles used to deliver a baby. The data is transmitted to
a computer across the room.
PHOTO BY HPS/WILL KIRK
Since April, when the students finished the project,
Edith Gurewitsch, assistant professor of gynecology and
obstetrics in the Johns Hopkins School of Medicine, has
supervised an institutional review board-approved pilot
study, testing the device during 15 deliveries performed by
physicians and a midwife. The participants wore the
electrodes under sterile gowns and gloves. Although some
fine-tuning has been required to ensure that the muscle
impulses are detected by the electrodes, Gurewitsch said,
"The device seems to work well." The obstetrics researcher
also is working with Allen and the student inventors, using
the device in a lab in which mock deliveries are performed
using a baby-size doll.
Generally, physicians or midwives apply minimal force
on the child during a routine delivery. But Gurewitsch
hopes to use the student-built device in her study of
complicated deliveries in which the baby's shoulder becomes
stuck behind the pubic bone. Several different techniques
can be used to extract the baby when this occurs. "Our
ultimate goal is to use the device to figure out which is
the best technique to use in these complicated deliveries,"
Gurewitsch said. "We want to find the technique that
requires you to use the least amount of force."
The device must be calibrated to each user. This is
done either shortly before or after the delivery, when the
user's forearm muscle impulses are recorded at rest and
while pulling with five pounds of force, then 10 pounds, as
measured by a dynamometer. The device can then produce an
accurate record of the force being used during delivery by
comparing it to the calibration readings.
The student inventors believe their device could also
be used for training and research in orthopedic surgery,
which can require the use of great force, and in preventing
sports injuries. For example, a baseball pitcher might use
the device to learn how to throw with considerable force
but not enough to cause an injury. The four students and
their instructor, Robert Allen, have obtained a provisional
patent covering their device.
Team leader William Tam, of Boston, received his
bachelor's degree in biomedical engineering in May and is
now a BME doctoral student at Johns Hopkins. "I have been
involved with design teams since my freshman year, and the
teams always find innovative ways to solve their proposed
biomedical problems," Tam said. "The course allowed me to
apply what I learned into my designs, and I tried to pass
the knowledge on to younger students in the class."
Yen Shi "Gillian" Hoe, of Singapore, is now a senior
majoring in biomedical engineering. "This was such a great
hands-on experience," she said. "It was so exciting to
bring our wireless instrument into the delivery room, where
the doctors could use it without interfering with their
I-Jean Khoo, also of Singapore, received her
bachelor's degree in biomedical engineering in May. She is
now working on a master's degree in biotechnology at the
University of Pennsylvania. "Science is a definitive field,
and I'd like to make a tangible contribution to society
through scientific discovery," she said.
Stanley Huang, of Toronto, received his bachelor's
degree in biomedical engineering in May and is currently
pursuing a master's degree in biomedical engineering at
Hopkins. "We went through many prototypes before we settled
on the design of this device," he said. "It was having
trouble picking up signals from the muscles, so we had to
use more sensitive electronics. I liked the idea of
applying what I'd learned to make something useful."
Related Web sites
Johns Hopkins Department of Biomedical Engineering
Collegiate Inventors Competition