Hypothermia is a very good thing for the body, says Mayo Clinic researchers, when it’s used after a person is resuscitated from cardiac arrest, that is. And what is the cooling temperature for therapeutic hypothermia?
It is 91.4 degrees Fahrenheit. This converts to 33 degrees Celsius. Normal body temperature is around 98.6 degrees Farhenheit. The purpose of therapeutic hypothermia after cardiac arrest resuscitation, is to slow down the metabolism of the brain. This protects the brain from damage caused by the cardiac arrest: lack of oxygen to the brain.
The latest research from Mayo Clinic lauds this technique. Says Alejandro Rabinstein, MD, a Mayo Clinic neurologist, “Therapeutic hypothermia is a neuroprotective strategy. Brain recovery is the main determinant of outcome for patients who survive cardiac resuscitation.” Therapeutic hypothermia is now the standard of care for cardiac arrest patients.
The study involved 192 cardiac arrest resuscitation patients, and over 100 of them were treated with therapeutic hypothermia. Numerous neurologic exams were given to the patients, including measurement of NSE: neuron-specific enolase, which is a marker in the blood for the extent of brain damage.
If blood has a high level of NSE, this is a reliable prediction of poor outcome following cardiac arrest without therapeutic hypothermia. However, when it comes to how valuable this NSE marker is in people who are cooled following cardiac arrest, less is known.
Nevertheless, Dr. Rabinstein’s study showed that elevated NSE levels were statistically associated with poorer outcomes in people who were given therapeutic hypothermia, but he still concluded that the level of NSE was not sufficiently reliable as far as estimating the prognosis of hypothermia-treated patients; this is because elevated NSE was also detected in some of the people who recovered well.
This component of the study, says Dr. Rabinstein, “deserves more attention.” He then explains, “It’s important for people to know that among patients treated with therapeutic hypothermia following resuscitated cardiac arrest, up to two-thirds of them may go home with good function. We are still examining how these patients recover in terms of higher intellectual faculties, but certainly these are results that were not even conceivable prior to the application of therapeutic hypothermia.” The full study report is in the Annals of Neurology (Dec. 2010).
Causes of sudden cardiac are: heart disease, heart attack, enlarged heart, diseased heart valves, electrical problems with the heart, and congenital heart disease.