Cooling the body is helpful

For the past 15 years, hypothermia therapy has been tested for many neurologic emergencies. Studies have provided clear evidence for protective effects; others have yielded mixed or conflicting results. Available evidence suggests that hypothermia therapy is more effective if it is applied soon after injury. This inhibits the complex cascade of processes that occurs at the cellular level after a period of ischemia. Induction of mild hypothermia (32 - 35°C) has been used as treatment of TBI, stroke, hepatic encephalopathy, MI, and other clinical conditions.. Indications are read more...

* Potential indications for hypothermia include cardiac arrest and cardiopulmonary resuscitation, perinatal asphyxia, TBI, ischemic stroke, acute MI, and perioperative hypothermia.
* Cardiac arrest and cardiopulmonary resuscitation:
o Between 1997 and 2001, 6 small clinical trials were conducted and reported improved 21 outcomes vs historical controls. Subsequently, 3 randomized controlled trials were performed and demonstrated a favorable outcome in the hypothermia group.
o Guidelines by the European Resuscitation Council and American Heart Association recommend hypothermia after cardiac arrest if the initial rhythm is ventricular tachycardia or ventricular fibrillation and to consider its use for other rhythms.
o A meta-analysis concluded that the number needed to treat (NNT) to leave the hospital in good neurologic recovery was 6.
o Current evidence suggests that patients should be cooled to 32 to 34°C for 12 to 24 hours, but this is subject to change as more information becomes available.
* Perinatal asphyxia:
o Hypothermia should be considered for newborn babies with perinatal asphyxia, especially those with mild to moderate injuries.
o Adverse effects seem to be minor, and studies support an NNT of 6.
o Target temperature should be 33 to 35°C, with some evidence suggesting that the lower range (33 - 33.5°C) is more effective; duration should be 48 to 72 hours.
* TBI:
o Hypothermia is effective in controlling intracranial hypertension.
o Lower intracranial pressure does not guarantee improved outcome; positive effects on survival and neurologic outcome have been achieved only in large referral centers with experience in hypothermia use, when treatment was applied within a few hours after an injury for more than 48 hours in patients with raised intracranial pressure.
o Management of adverse effects, such as hypotension or hypovolemia, is of key importance.
o Rewarming should be done very slowly for at least 24 hours.
o Patients with TBI with mild hypothermia (33 - 35°C) at admission, who are hemodynamically stable, should be allowed to remain in a hypothermic state.
o Hypothermia can also be used to control intracranial pressure in the later stages after TBI, but no evidence exists that neurologic outcome is improved by such delayed application of hypothermia.
* Ischemic stroke:
o Animal studies and some clinical data suggest that hypothermia could limit neurologic injury in stroke, but insufficient evidence exists to recommend its use outside clinical trials.
o Hypothermia could be used to control intracranial pressure in patients with middle cerebral artery infarction and cerebral edema and could improve their outcome.
* Acute MI:
o No evidence demonstrates that hypothermia is harmful to the injured heart, and rapid induction of hypothermia might reduce infarct size in patients with anterior MI.
* Perioperative hypothermia:
o Although intraoperative hypothermia is widely used, firm evidence from randomized controlled trials is often absent.
o Animal studies and initial clinical trials using hypothermia for spinal protection in major vascular surgery have shown promising results.
o However, a large clinical study in patients undergoing cerebral aneurysmal clipping noted no substantial effect of hypothermia.
o Evidence suggests that rapid rewarming can be harmful and might cancel out potential benefits of preceding hypothermia treatment or even make the neurologic situation worse.
o Fever is a common complication in patients with various types of neurologic injury and is independently associated with increased risk for adverse outcomes.
Read recent review article published in Lancet..