Hypothermia is defined as below normal temperature, usually below 95.9 degrees Fahrenheit or 35.5 degrees Celsius in humans. This is a dangerous state under most circumstances, and can run a variety of risks. Yet in some cases, dropping the body temperature below these levels can be highly desirable from a medical standpoint. When this is done purposefully it is called therapeutic hypothermia.
For a long time, there has been significant evidence that cooling the body down during many forms of heart surgery can greatly reduce risk of stroke or ischemia. It is now standard in many significant heart surgeries to employ this step, though there are other surgeries that are performed on the fully warm beating heart. Doctors have developed several ways of inducing hypothermia. Fluid can be injected into veins that cools the body down, or blankets and other things like fluid filled packs may be placed on person to create therapeutic hypothermia; these are know as invasive and non-invasive methods, respectively.
Therapeutic hypothermia was long looked at as a step before trauma (surgery) to the heart occurs, but views on this have changed. Studies in the late 1990s and early 2000s also showed that cooling the body down after someone has suffered a heart attack may be extremely beneficial too. One of the great risks of myocardial infarction is that people will experience blood clot formation which can result in an ischemic stroke that may cause death or brain damage. Prevention in between the attack and this undesirable outcome has been found to reduce this risk, and is now recommended in some hospitals as first line treatment for adults, as a form of neuroprotection.
What is interesting about therapeutic hypothermia is that treatment is verifiably effective, but the reason why it works isn’t entirely known. Currently, there are only theories that haven’t been proven, which may explain why this method can reduce stroke risk. It may be that more than one body system from the cellular level upward is affected by a reduction in body temperature, in a manner that positively can reduce damage to the brain and/or risk of stroke
It can’t be said that therapeutic hypothermia is without risk. It can make people bleed more profusely, cause extreme shivers which must be controlled with medication, and it may also create irregularities in heart rhythm that could be dangerous to a recovering heart. Another risk present is elevated chance of getting infections, and this can be considered a high risk in hospital settings where infectious matter is more likely to exist in high amounts. Care must additionally be taken to not allow the temperature to fall below 89.6 degrees F (32 C), and when the treatment is over, getting the body temperature to return to normal must be a slow process, because allowing quick return to a normal temperature may cause death.