This study is a prospective, multi-centre, randomized,controlled trial to compare the efficacy of long-term mild hypothermia with normothermic intensive management in patients with poor-grade aneurysmal subarachnoid hemorrhage.

The primary hypothesis is that the induction of mild hypothermia (maintained at 32-35℃) for at least 5 days would improve the outcome of patients at six months post hemorrhage compared with normothermia.

Aneurysmal subarachnoid hemorrhage (aSAH), especially poor-grade aSAH, is a medical emergency with very high morbidity and mortality rates. SAH constitutes a major public health concern in developed and developing countries. There were several clinical trials of hypothermia for aSAH conducted, however, with conflicting results.

Hypothermia therapy treatment is currently used in our department and other large neurosurgical centers across China to decrease the intracranial pressure (ICP), mitigate some of the destructive processes, and improve the functional outcome of patients with poor-grade aSAH. When the decision was made, the patients would be placed in wrapped cooling blankets or intravascular cooling device after they were sedated, intubated and mechanically ventilated. The patients would receive continuous infusions of some drugs using an infusion pump to prevent shivering. Once the patient's rectal, nasopharyngeal or blood temperature reached 32˚C, it was kept at approximately that temperature (32-35˚C) 3 to 7 days. Then the patients were passively rewarmed to a temperature of 36 to 37˚C at a rate no greater than 0.25˚C/hour, by gradual adjustment of the blanket thermostat.

The present multi-center, randomized controlled trials is designed to investigate the efficacy and safety of long-term (3 days) mild hypothermia versus normothermia on the outcome of patients with poor-grade aSAH. The primary outcome is the neurological function assessed at 1,3, 6 months post injury with the Glasgow Outcome Score (GOS). Additionally, the following data will also be recorded and compared: the baseline data, Glasgow Coma Score,imaging examination (e.g. CT scan), intracranial pressure, laboratory tests (e.g. blood routine test, liver and kidney function, blood gas analysis, etc), the complications (e.g. pneumonia, significant bleeding) and so on.

Inclusion Criteria:

• Age 18 - 65 years within 72 hours after subarachnoid hemorrhage;
• Neurosurgical clipping or coiling for aneurysm;
• Hunt-Hess IV-V scale;
• The intracranial pressure is more than 20 mmHg.

Exclusion Criteria:

• GCS of 3 with bilateral fixed and dilated pupils;
• No spontaneous breathing or cardiac arrest at the scene of hemorrhage;
• No consent;
• Pregnancy.