Hypothermia Can Help a Stroke

Hypothermia may help stroke.

Therapeutic efforts to minimize brain injury after a stroke use a multi-pronged approach aimed at controlling blood clots while preserving brain tissue.

Brain Damage From Stroke

A stroke is caused by a cutoff of blood supply to the brain- this interruption of blood flow within a cerebral artery is called an infarct. The resulting damage to the brain itself is called ischemia, which is a lack of oxygen and vital nutrients to cells of the brain.

Brain ischemia induces a complex cascade of events- including blood pressure changes, the release of toxins that damage brain cells, and disruption of cerebral metabolic activity. In fact, the specific alterations that occur in infarcted brain tissue continue to be the focus of scientific experiments throughout the world.

Treatment for Stroke 

After a stroke, there is an extremely limited time window during which the administration of powerful blood thinners to re-establish blood flow may be given. After that brief time period, which lasts only a few hours after the initial onset of stroke symptoms, some less potent blood thinners may be administered to prevent expansion of blood clots. Treatment with any blood thinners requires precision and care because bleeding may occur as a complication of treatment- even under the most painstakingly careful circumstances.  One of the huge priorities in acute stroke care includes the use of a variety of medical and surgical methods to stabilize the body’s condition to maintain the optimum state for cerebral healing.

Hypothermia for Stroke Treatment 

Over 100 years ago, it was first observed that stroke-induced alterations in metabolic activity in the brain contribute to cerebral damage, and thus exacerbate long-term disability. Warmer body temperature increases metabolic activity while cooler body temperatures decrease metabolic activity.

Therefore, warmer body temperature intensifies the cerebral damage of a stroke while cooler body temperature reduces or stabilizes cerebral damage. Now, hypothermia is being studied as a way to reduce the damage of a stroke. An article published in the July 2014 issue of the journal, “Neurohospitalist,” describes how hypothermia decreases cerebral blood flow and reduces the oxygen needs of the brain. This process has been shown to help reduce the damage caused by a stroke.

Animal Studies

A research study using mice has demonstrated protection against stroke-induced damage by inducing controlled hypothermia. When the mice were intermittently cooled down for at least 1.5 hours per session, there were measurable improvements in neurological function. Similarly, continuous hypothermia lasting for 12 hours was found to be neuroprotective, while continuous hypothermia lasting for only 6 hours was not found to have a sufficient protective effect. These results can help guide human research studies.

Hypothermia for Stroke

Several challenges to the practical use of hypothermia have prevented it from becoming an established stroke treatment over the years. But that may be changing. There are several ongoing clinical trials worldwide which are investigating the use of hypothermia in stroke patients.

Data is expected to include important details on the optimal timing and duration of effective hypothermia administration as well as the best methods for cooling down patients without causing damage to the brain or other organs. Studies also should serve to identify which target temperatures are most efficient. Currently, temperature ranges between 34 degrees C and 35 degrees C are considered to be hypothermic.

Future directions

The use of controlled hypothermia holds potential as a complementary method of treating stroke, along with blood thinners, fluid management, electrolyte regulation, blood pressure maintenance, and prevention of infection.

New directions in stroke care include a muti-faceted approach aimed at saving brain cells and directing revitalization of brain function to optimize physical and mental functioning after a stroke.


Karnatovskaia LV, Wartenberg KE, Freeman WD. Therapeutic hypothermia for neuroprotection: history, mechanisms, risks, and clinical applications, Neurohospitalist, July 2014

Sherman AL, Wang MY, Hypothermia as a clinical neuroprotectant, Physical Medicine and Rehabilitation Clinicas of North America, August 2014

Xu SY, Hu YF, Li WP, Wu YM, Ji Z, Wang SN, Li K, Pan SY, Intermittent hypothermia is neuroprotective in an in vitro model of ischemic stroke, International Journal of Biological Sciences, July 2014

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