By EMS1 Staff
DALLAS — It is current standard practice to give pediatric patients presenting with oxygen deprivation 100 percent oxygen in order to prevent brain damage. Now researchers are saying this may actually cause additional harm to patients.
University of Texas Southwestern Medical Center researchers found that mice that received less than a minute of 100 percent oxygen after oxygen deprivation had suffered “far greater rates of brain-cell death” than those allowed to recover with room air.
“This study suggests 100 percent oxygen resuscitation may further damage an already compromised brain,” said Dr. Steven Kernie, associate professor of pediatrics and developmental biology and senior author of the study, which appears in the July issue of the Journal of Cerebral Blood Flow & Metabolism.
Most of the damage incurred involved cells that create myelin, a fatty substance that coats nerve cells and allows for faster transmittal of electrical signals. Electrical signals have a direct effect on coordination. Infants have much less myelin, also called “white matter,” than adults
“Patients with white-matter injuries develop defects that often result in cerebral palsy and motor deficits,” Dr. Kernie said.
In their study, the researchers briefly deprived mice of oxygen, then gave them either 100 percent oxygen or room air, which contains about 21 percent oxygen, 78 percent nitrogen and 1 percent other gases, stated in a press release.
According to the study, mice given 100 percent oxygen fared worse than those given room air after 72 hours. For example, they experienced a more disrupted pattern of myelination and developed a motor deficit that mimicked cerebral palsy.
“We wanted to determine whether recovery in 100 percent oxygen after this sort of brain injury would exacerbate neuronal injury and impair functional recovery, and in these animals, it did impair recovery,” Dr. Kernie said.
“Our research shows even brief exposure to 100 percent oxygen during resuscitation actually worsens white-matter injuries.”
Dr. Kernie said adding pure oxygen to the damaged brain increases a process called oxidative stress, caused by the formation of highly reactive molecules. The researchers found, however, that administering an antioxidant, which halts the harmful oxidation process, reversed the damage in the mice given 100 percent oxygen.
“Further research is needed to determine the best possible concentration of oxygen to use for optimal recovery and to limit secondary brain injury,” Dr. Kernie said. “Research is now being done to determine the best way to monitor this sort of brain damage in humans so we can understand how it correlates to the mouse models. There are many emerging noninvasive technologies that can monitor the brain.”
Information from a UT Southwestern Medical Center press release was used in this report.