Hypothermia helps brain heal after cardiac arrest

Cooling body temperature to levels consistent with hypothermia improves survival when induced after cardiac arrest and also promotes growth factors important for the brain’s recovery, suggests a study performed by researchers in the department of emergency medicine at the University of Pittsburgh School of Medicine. Preliminary results of their study were reported today at the 2003 Annual Meeting of the Society of Academic Emergency Medicine (SAEM) in Boston.
From University of Pittsburgh Medical Center:Hypothermia helps brain heal after cardiac arrest, finds University of Pittsburgh study

Preliminary results presented at Society of Academic Emergency Medicine Meeting

BOSTON, May 30 ? Cooling body temperature to levels consistent with hypothermia improves survival when induced after cardiac arrest and also promotes growth factors important for the brain’s recovery, suggests a study performed by researchers in the department of emergency medicine at the University of Pittsburgh School of Medicine. Preliminary results of their study were reported today at the 2003 Annual Meeting of the Society of Academic Emergency Medicine (SAEM) in Boston.

Although the study involved animals, the findings already had an influence on the management of cardiac arrest patients being treated at the University of Pittsburgh Medical Center (UPMC), where the lead researcher is also a practicing emergency medicine physician.

Cardiac arrest is the sudden, abrupt loss of heart function. Death usually occurs within minutes unless cardiopulmonary resuscitation (CPR) and rapid defibrillation is available. As cardiac arrest progresses, blood flow to the brain ceases. If a patient survives long enough to make it to the hospital, the patient often will be in a coma and at risk of permanent brain injury. In fact, less than 10 percent of patients make it through the chain-of-survival (early access to care, early CPR, early defibrillation and early advanced care). The Pitt researchers sought to find out if hypothermia treatment played a role in survival from cardiac arrest and brain recovery.

In animal studies, the researchers found that when the animals were cooled to 33 degrees Celsius (91.4 degrees Fahrenheit) beginning one hour after cardiac arrest, there was 100 percent survival, whereas 75 percent of the animals left at normal temperature of 37?C (98.6?F) survived. Furthermore, microscopic brain injury was reduced by half, and some animals showed functional improvement in as little as 12 hours after cardiac arrest was induced. Conversely, the animals left at normal temperature after cardiac arrest showed little or no functional improvement.

Previous studies from the researchers detected increased levels of growth factors derived from brain cells when hypothermia was induced after cardiac arrest. In this current study, the researchers also found that levels of growth factors derived from glia-cells in the brain that support nerve cells are increased by hypothermia as well. These growth factors may play an important role in brain recovery after cardiac arrest.

Many researchers have speculated that cooling the brain would slow down harmful progression after injury, but these studies suggest that cooling the brain may actually stimulate brain recovery.

“Although it is known from clinical studies that cooling the brain offers therapeutic benefits to patients, further studies need to be done to determine how much the brain should be cooled and for how long,” said Clifton Callaway, M.D., assistant professor of emergency medicine at the University of Pittsburgh School of Medicine. “By understanding the molecular mechanisms of brain recovery in cardiac arrest, we can prescribe a more effective treatment.”

Based on this research and other studies, Dr. Callaway and colleagues are already beginning the routine cooling of cardiac arrest patients who are brought to the emergency department at UPMC Presbyterian, UPMC’s flagship hospital.


Substack subscription form sign up
The material in this press release comes from the originating research organization. Content may be edited for style and length. Want more? Sign up for our daily email.

Comments are closed.