What do the treatments for 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 decrease swelling in the brain and lessen damage.

Recently, Doylestown Hospital started using the body-chilling treatment known as medical hypothermia for select cardiac arrest patients. Eugene Vallely, RN, a critical care nurse educator, and Jen Harrar, RN, an Emergency Department nurse, who oversee the treatment, explain how it works.

“We lower the body temperature in these patients from a normal 98.6 degrees to around 91.4 degrees. The cooling takes about six hours and slows the production of free radicals, which are molecules that break down the cell’s DNA and other components. Free radicals can destroy brain cells.

“The patient is placed in a medically induced coma, which is not life-threatening, and wrapped in a Criticool™ suit,” explains Mr. Vallely. “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. Chilling has also been used for open heart surgeries since the 1950s. Medical hypothermia holds great promise in the preservation of 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 Ms. 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 helps to preserve brain function once oxygen flow has returned.

In addition to cardiac arrest patients, the medical hypothermia treatment will also be used on select stroke patients.