In the not too distant past, suffering a cardiac arrest outside of the hospital rarely included a complete recovery. Today, an innovative new treatment, called therapeutic hypothermia, offers many post-cardiac arrest patients a recovery that would have been deemed miraculous just a short time ago.
When someone suffers cardiac arrest, the heart suddenly stops beating due to an abnormal heart rhythm called ventricular fibrillation. Within seconds, the victim loses consciousness, collapses and has no pulse. Only immediate emergency treatment to restart the heart, such as CPR (cardiopulmonary resuscitation) and external defibrillation (electrical shock), can prevent death. Time is the key factor in survival for these victims. The American Heart Association recommends resuscitation within five minutes of collapse or sooner.
Because cardiac arrest stops the heart from pumping blood, the body and brain are deprived of oxygen. This deprivation causes cardiac arrest survivors to suffer brain damage that leads to poor neurological outcomes or death.
What is therapeutic hypothermia?
Therapeutic hypothermia is a process by which critical care doctors lower a patient’s body temperature, after the heart is restarted, to reduce the risk of brain injury following a period of insufficient blood flow. Under monitored sedation, patients are wrapped in specialized cooling pads to rapidly lower the body temperature to levels between 89.6 degrees Fahrenheit to 93.2 degrees Fahrenheit. (Normal body temperature is 98.6 degrees Fahrenheit.) Once cooled for 24 hours, patients are slowly re-warmed to a normal temperature. This therapy has been shown to significantly reduce brain damage and improve survival after cardiac arrest.
“Therapeutic hypothermia has become the gold standard in the treatment of post-cardiac arrest patients,” said Stephen W. Trzeciak, M.D., Emergency Medicine and Critical Care physician at Cooper.
Cooper University Hospital is leading South Jersey in utilizing therapeutic hypothermia. To date, nearly 100 hypothermia treatments have been performed, resulting in what Cooper cardiologist Perry J. Weinstock, M.D., Head of the Division of Cardiovascular Disease, describes as “a difference in (patient) outcomes that can not be overstated.”
How does therapeutic hypothermia work?
While cardiac arrest requires emergency treatment to restart the heart to prevent death, the restoration of circulation results in what is called reperfusion injury. Reperfusion injury refers to tissue damage caused by chemical reactions that occur when blood supply returns to tissue after a period of insufficient blood supply. The absence of oxygen and nutrients from blood creates a condition in which the reperfusion (the restoration of circulation) results in inflammation and cell damage.
Mild hypothermia is thought to suppress many of the chemical reactions associated with reperfusion injury. Therapeutic hypothermia has been shown to reduce mortality of successfully resuscitated cardiac arrest victims by 35 percent, and increase the chance of good neurologic outcome by 39 percent.
Where is therapeutic hypothermia available?
In its updated 2005 guidelines, the American Heart Association identified induced hypothermia as one of several beneficial therapies in the post-resuscitative care of cardiac arrest.
Yet, hypothermia treatment is unavailable at many hospitals.
“It is extremely important that emergency response personnel, area physicians and the community are aware that this proven treatment is not available at every hospital, and that Cooper is experienced in providing rapid and effective cooling for cardiac arrest victims,” said Cooper emergency medicine physician J. Hope Kilgannon, M.D., who also conducts research on post-cardiac arrest care.
“The longer the time that lapses between cardiac arrest and hypothermia treatment, the less successful the treatment may be,” Dr. Kilgannon said.
Remember, cardiac arrest can strike without warning. If you witness a cardiac arrest, call 9-1-1 or your local emergency response number immediately, and start CPR. The American Heart Association recommends that people learn both CPR and the simple procedure to operate an automated external defibrillator (AED). CPR and AED’s save lives.