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发帖数: 768 | 1 Device Measures Brain Temperature Non-Invasively: Monitoring Could Be
Critical in Life-Saving Cooling Therapy
ScienceDaily (May 2, 2011) — Doctors have long sought a way to directly
measure the brain's temperature without inserting a probe through the
skull. Now researchers have developed a way to get the brain's precise
temperature with a device the diameter of a poker-chip that rests on a
patient's head, according to findings presented May 1 at the annual
meeting of the Pediatric Academic Societies in Denver.
This is the first time that anyone has presented data on the brain
temperature of a human obtained non-invasively," said principal
researcher Dr, Thomas Bass, a neonatologist at Children's Hospital of
The King's Daughters in Norfolk, Va., and a professor of pediatrics at
the hospital's academic partner, Eastern Virginia Medical School.
The research also suggests that an injured brain can be significantly
warmer than the body, a finding critical to cooling therapies that
reduce brain damage in everyone from elderly heart attack victims to
hypoxic newborns.
"Knowing the actual brain temperature may allow us to improve outcomes
by keeping the brain at an optimum temperature," said Dr. Bass.
With the help of a $750,000 National Institutes of Health grant, a
research team led by Dr. Bass adapted an instrument that calculates
temperatures by detecting microwave emissions produced by all human
tissue.
Those microwaves pass unimpeded through the skull, like light passing
through a sheet of glass. As tissue temperatures increase, the emissions
grow more intense. Engineers calibrated the device to measure the
temperature of brain tissue 1.5 centimeters beneath the skull.
In the trial whose results were presented, the device was placed on
the heads of infants undergoing cooling therapy at CHKD. The device's
brain temperature readings were correlated with rectal and esophageal
temperatures. The difference in temperature between the brain and the
body recorded by other means was as high as 5.4% Fahrenheit.
"That's difference is larger than we expected," Dr. Bass said.
Dr. Bass, who pioneered research on cooling therapy for hypoxic
newborns, and set about this research because he believed the therapy
could be improved if doctors knew precise temperature of the damaged
organ, the brain.
Hypoxic brain damage in infants occurs most often in full-term births
when the child suffers oxygen loss either immediately before or during
delivery. Because of a quirk in the brain, a child can be revived but
brain cells continue to die over several days, resulting in brain damage
or death. Doctors could do little to stop this progression; parents
often watched helplessly as their sons and daughters literally died
before their eyes.
Based on the observation that children rescued from freezing ponds after
extended periods of time suffered little or no brain damage, cooling
therapy involves chilling an infant's body to 92 degrees for 72 hours
after brain injury.
A clinical trial on the therapy showed that cooling the child stops or
reduces the progression of brain cell death, drastically reducing
brain damage and death. The results were so positive that the therapy is
now standard in advanced neonatal intensive-care units worldwide.
Cooling therapy is now used with other patients as well, including heart
attack victims whose brains have suffered oxygen deprivation.
Because cooling therapy's success relies on the temperature of the
brain, precise readings of the brain's temperature is likely to
improve a therapy that's already proven remarkably effective.
Children's Hospital of The King's Daughters is the only freestanding
pediatric hospital in Virginia. |
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