COOLING THERAPY FOR THE HEART
06/25/2008
Cooling therapy can aid the brain after cardiac arrest.
What do a sprained ankle and an oxygen-deprived brain have in common?
Just as ice can help minimize swelling and bruising in a sprained ankle, cooling the body’s core temperature can help control swelling in the brain and lessen damage.
Doylestown Hospital recently started using the body-chilling treatment known as medical hypothermia with cardiac arrest patients using the a Criticool™ suit. Eugene Vallely, a critical care nurse educator and Jen Harrar, an Emergency Department nurse, oversee the treatment. This is how it works.
“We lower the body temperature in selected patients from a normal 98.6 degrees to around 91.4 degrees. The cooling, which takes about six hours, stops the formation of free radicals which destroy brain cells.” Eugene says. “Using the Criticool™ suit, the patient is placed in a medically non-life-threatening induced coma. The coma is important as it prevents shivering, which would raise the body temperature. After 24 to 28 hours, the patient is gradually rewarmed at about one degree an hour.”
The practice of chilling the body for medical treatment dates to ancient times, when packed snow was used to control hemorrhaging. It was used during early open heart surgeries in the 1950s and has been evaluated in studies since then, with mixed results. Today many experts believe that medical hypothermia holds great promise in preserving vital organ function.
How does medical hypothermia work?
When the heart stops abruptly, as in cardiac arrest, blood flow is interrupted and organs are deprived of oxygen. If the brain is denied oxygen for more than three minutes, it begins to die. According to Jen Harrar, if the body is cooled within four to eight hours after the heart stops, and has been restarted, the brain’s metabolic rate slows and it can survive with less oxygen. Medical hypothermia also controls swelling and aids in the process of restoring brain activity once oxygen flow has returned.
Since the use of the therapy began earlier this year, it has been used only for patients in cardiac arrest, but shortly, we will begin using it for stroke patients.
