Reductions in brain temperature by 2°C to 5°C provide neuroprotection in newborn and adult animal models of brain ischemia.Brain cooling has a favorable effect on multiple pathways contributing to brain injury, including excitatory amino acids, the cerebral energy state, cerebral blood flow and metabolism, nitric oxide production, and apoptosis. Brain cooling is effective in reducing the extent of brain injury even when it is initiated up to 5.5 hours after brain ischemia in near-term sheep fetuses.But, epidemiological data showed that, in non-developed countries and areas,Whole-body hypothermia is related to the increased mortality and brain injury. The cause is unclear.
Among term infants, hypoxic-ischemic encephalopathy due to acute perinatal asphyxia remains an important cause of brain injury in childhood. Infants with moderate encephalopathy have a 10 percent risk of death, and those who survive have a 30 percent risk of disabilities. Sixty percent of infants with severe encephalopathy die, and many, if not all, survivors are disabled. Whole-body hypothermia reduces the risk of death or disability in infants with moderate or severe hypoxic-ischemic encephalopathy.