2003 info - cooling vs cardiac arrest vs brain damage

June 2, 2003

Cooling after cardiac arrest helps heal brain

At the Annual Meeting of the Society of Academic Emergency Medicine
held in Boston this year, researchers from the University of
Pittsburgh School of Medicine reported that inducing hypothermia
following cardiac arrest improves survival and promotes growth factors
in the brain that aid in recovery. Cardiac arrest is the sudden loss
of heart function that results in death in the majority of cases and
in brain injury in many of the survivors.

The researchers found that laboratory animals cooled to 33 degrees
Celsius within one hour following cardiac arrest experienced a 100
percent survival rate compared to 75 percent of animals not cooled.
Microscopic examination of brain tissue found a 50 percent reduction
in brain injury in the cooled group compared to the animals who did
not undergo hypothermia. An increased level of glia-cell derived
growth factors that support nerve cells were found in the brains of
the cooled animals, which may assist in brain recovery. This shows
that cooling, rather than merely slowing the injury process, actually
stimulates recovery. Additionally, the team observed functional
improvement in the cooled group twelve hours following cardiac arrest
compared to little functional improvement in animals that had not been
cooled.

Assistant professor of emergency medicine at the University of
Pittsburgh School of Medicine,.Clifton Callaway, MD, stated, "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. By
understanding the molecular mechanisms of brain recovery in cardiac
arrest, we can prescribe a more effective treatment."

Dr Callaway and his colleagues are now routinely cooling cardiac
arrest patients at the University of Pennsylvania Medical Center
Presbyterian Hospital based on these and previous findings.

—D Dye