The Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury

Eligible patients will be randomised in the pre-hospital setting or on admission to the Emergency Department. POLAR study trained paramedics and physicians will screen patients in the pre-hospital setting. Eligible patients will be randomised if they fulfil the inclusion criteria with no pre-hospital exclusion criteria. Those randomised to the normothermia group will follow standard care. For those randomised to the "cooling arm", pre-hospital prophylactic hypothermia will be induced by exposure and by infusing up to 2 litres intravenous cold (4°C) 0.9% sodium chloride aiming for a core temperature of 35°C during transport. In the emergency department the "cooling arm" patients will be assessed to exclude significant bleeding and, once significant bleeding has been excluded, surface cooling vests/wraps will be applied to reach the target core temperature of 33°C. The patient will be then maintained at this temperature for a further 72 hours. Patients with significant bleeding will have cooling withheld until it is safe to decrease the temperature to the target core temperature of 33°C. Patients who have not been randomised pre-hospital will be re-screened in the ED. Eligible patients will be randomised if they fulfil the inclusion criteria with no ED exclusion criteria. Hypothermia will be induced by administration of up to 2L intravenous ice-cold (4°C) 0.9% sodium chloride followed by application of the surface cooling vests/wraps to achieve the target core temperature of 33°C. Patients allocated to standard 'normothermic' care will be maintained at a core temperature of 37°C ± 0.5°C.

Inclusion criteria

• Blunt trauma with clinical diagnosis of severe TBI and GCS <9
• Estimated age ≥ 18 and < 60 years of age
• The patient is intubated or intubation is imminent

Exclusion criteria

• Pre-hospital:

• Clinical diagnosis of drug or alcohol intoxication as predominant cause of coma
• Randomisation unable to be performed within 3 hrs of estimated time of injury
• Estimated transport time to study hospital >2.5hrs
• Able to be intubated without drugs
• Systolic BP <90mmHg
• Heart rate > 120bpm
• GCS=3 + un-reactive pupils
• Penetrating neck/torso injury
• Known or obvious pregnancy
• Receiving hospital is not a study site
• Evidence of current anti-coagulant treatment
• Emergency Dept:

• Clinical diagnosis of drug or alcohol intoxication as predominant cause of coma
• Randomisation unable to be performed within 3 hrs of estimated time of injury
• Able to be intubated without drugs
• GCS=3 + un-reactive pupils
• Persistent Systolic BP <90mmHg
• Clinically significant bleeding likely to require haemostatic intervention, for example:

• Bleeding into the chest, abdomen or retro-peritoneum likely to require surgery +/- embolisation
• Pelvic fracture likely to require surgery +/- embolisation
• More than two long bone fractures requiring operative fixation
• Penetrating neck/torso injury
• Positive urine or blood pregnancy test
• Evidence of current anti-coagulant treatment
• In the treating clinician's opinion, "cooling" is not in the patient's best interest