If you think getting a good night's sleep at home is hard, try
catching 40 winks at the South Pole! It's not such an easy task,
says Mayo College of Medicine Professor Dr. Bruce D. Johnson.
According to Johnson, sleepers at the South Pole report an
oxygen saturation of 79 percent at rest — about 20 percent
lower than “normal” at-rest saturation readings. In
short, Johnson says, slumber at the South Pole is physiologically
like sleeping at an altitude of 16,000 feet, which is precisely why
he and his research team recently made their second trek to
Antarctica to study altitude illnesses with the VivoMetrics
LifeShirt in tow.
Johnson and his crew used the LifeShirt garment, which contains
cardiopulmonary and movement sensors, to provide and record
valuable information from volunteer sleepers at the South Pole. The
volunteers' vitals are monitored during sleep at sea level using
the LifeShirt, and then compared via LifeShirt readings to sleep at
the Pole.
“At altitude, we tend to have many pauses or apneas in a
very consistent pattern that can go on for much of the night. Every
time you have an apnea, your oxygen drops lower. These are the
things we are looking at, and these are the details that LifeShirt
helps us monitor,” Johnson said.
A PhD with a background in respiratory physiology and
cardiovascular diseases, Johnson has long harbored an interest in
human environmental physiology — “how the systems of
the body work together and adapt to environmental
conditions.” His experiences in the field under his mentor,
respiratory scientist Jerome Dempsy, lead Johnson to LifeShirt.
“We've been using LifeShirts for years,” Johnson
said. “Since we do field work, and we're trying to find ways
to collect data, it was one of the few systems available that
allowed us to monitor breathing, heart rate, oxygen saturation and
other variables in ambulatory people,” he said.
In the years since its inception, LifeShirt has often been used
to monitor the conditions of people in extreme situations,
including racecar drivers and firemen. Today, LifeShirts are even
being used by the Philadelphia Flyers hockey team.
Alex Derchak, principal scientist behind the LifeShirt, said
applications for the monitoring technology are endless, especially
within the home care industry.
“[Home care] is definitely the direction that the
technology is going, but there is a lot of work to be done between
here and there,” Derchak said. “It starts as a
laboratory device and is tested by fire in the field, then it
becomes smaller and lighter and is eventually introduced into the
home care market. We're definitely on that path.”
According to Derchak, adapting LifeShirt's technology to the HME
market would allow providers to monitor daily remote vital signs of
their patients, which would assist in chronic disease management
for patients with COPD, congestive heart failure or even
diabetes.
“The work that Dr. Johnson is doing is really going to
inform chronic disease management practices in the future, and a
device like LifeShirt makes it a real possibility,” Derchak
said.
Johnson has also tapped in to the many applications for
LifeShirt. In addition to his studies in the Antarctic, Johnson
said he uses the VivoMetrics device in his domestic studies in the
Mayo College's Colorado High Altitude Tent.
Johnson's LifeShirt readings are part of a three-year study on
altitude illness funded by the National Science Foundation.
Currently in its second year, the goal of the study, according to
Johnson, is to pinpoint the “base line characteristics”
that contribute to altitude illness — age, gender, activity
levels, sleep history, body habitus — in an effort to stem
the frequency of the illness. Johnson said the data he and his
researchers gather will also be beneficial in treating other
diseases including lung disease and heart failure, which is the
leading cause of hospitalizations in people over the age of 65.
Johnson said the sleep study has collected data from about 200
volunteers, and of those, about 70 participated in the LifeShirt
segment. Johnson said he hopes to make one more research trip to
Antarctica before presenting the study's findings.
