A low body temperature can kill you, but it can also save your life.
Therapeutic hypothermia dramatically improves the chances of recovery among those who suffer from cardiac arrest, according to George A. Lopez, MD, assistant professor of neurology at Baylor College of Medicine in Houston . Lowering the body's temperature after a cardiac arrest or acute stroke dramatically increases the chances for surviving and improves the neurological outcome.
Traditionally, survivors of sudden cardiac death who are resuscitated but do not regain consciousness rarely wake up again. Now, however, physicians have a potential solution.
"The tide is changing where before we wouldn't be able to do anything," said Lopez, also a neurologist at The Methodist Hospital. "Now we're at the other end of the spectrum where we actually have a treatment to protect their brain, help them survive and improve their neurological outcome."
Lopez has investigated the effectiveness of two different cooling methods that lower the body's temperature from 98.6° F to 89° F without imposing severe risks. Lopez has had success using either a catheter, which chills blood internally through a large vein in the leg or chest, or a specially designed body wrap that circulates cold water outside of the skin.
Both techniques temporarily reduce the brain's oxygen needs and protect against several harmful biochemical mechanisms, which can cause the death of neurons in vulnerable regions of the brain, particularly the hippocampus and cerebellum.
Hypothermia may also be applied in instances of traumatic brain injury, aneurysm surgery, resuscitation and liver failure. In the latter case, the liver is hampered in its role of cleansing toxins that can travel to the brain and cause it to become distended. Hypothermia has been shown to decrease the amount of swelling and increase the chance of surviving until the liver regenerates and heals or until the patient receives a new transplanted liver.
Although first used therapeutically in the 1950s for special surgical procedures, hypothermia has recently been re-investigated - but only in very few hospitals around the world—because of its role in protecting brain cells. Lopez believes its limited use derives from lack of knowledge of the potential treatment's benefits.
"My dream is to have this treatment offered on a much wider basis than is currently being offered," Lopez said. "Hypothermia should be a standard of care in patients who have survived sudden cardiac death."
In an effort to spread the word, Lopez recently organized a symposium, "Hypothermia in Clinical Practice: From Bench to Bedside - Applications for Emergency Medicine, Neurology, Cardiology, Neurosurgery, and the ICU." The symposium was attended by about 100 doctors, nurses, and other health care professionals from several areas of medicine with the intent of publicizing the positive attributes of therapeutic hypothermia.
"Hypothermia is useful in a variety of different medical specialties, so the seminar was intended for a fairly wide audience," Lopez said. Another symposium is planned for 2005.
Disseminating information about therapeutic hypothermia has so far proved to be an uphill battle.
"Very few hospitals are offering hypothermia as a treatment for these patients," said Lopez, who points out that Hermann Hospital remains the only hospital in Houston that offers the cooling therapy to victims who sustain neural damage.
"My plan is to help bring forward this information, put it out into the mainstream and get more people using it because we know it's helpful," Lopez added.
Lopez is cooperating with The Methodist Hospital to implement hypothermia in cases of acute ischemic stroke, in which blood supply to the brain is decreased or blocked, and has also worked with the Houston Fire Department. He is currently participating in a national study, funded by the National Institutes of Health through the University of California at San Diego, to conduct further research on hypothermia's applications for stroke victims.