POLAR logoPOLAR-RCT: Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury – Randomised Controlled Trial

The POLAR-RCT was a prospective, randomised controlled multi-centre trial of early and sustained prophylactic hypothermia in patients with severe traumatic brain injuries.

To determine whether early cooling of patients with severe traumatic brain injury (TBI) is associated with better outcomes.

TBI is a leading cause of death and long term disability, particularly in young adults. Studies from Australia have shown that approximately half of those with severe TBI will be severely disabled or dead 6 months post injury. Given the young age of many patients with severe TBI and the long term prevalence of major disability, the economic and more importantly the social cost to the community is very high.

Pre-hospital and hospital management of patients with severe brain injury focuses on prevention of additional injury due primarily to lack of oxygen and insufficient blood pressure. This includes optimising sedation and ventilation, maintaining the fluid balance and draining cerebrospinal fluid (CSF) and performing surgery where appropriate. In recent years there has been a research focus on specific pharmacologic interventions, however, to date there has been no treatment that has been associated with improvement of neurological outcomes.

One treatment that shows promise is the application of hypothermia (cooling). This treatment is commonly used in Australia to decrease brain injury in patients with brain injury following out-of-hospital cardiac arrest. Cooling is thought to protect the brain using a number of mechanisms. There have been a number of animal studies that looked at how cooling is protective and also some clinical research that suggests some benefit. However, at the current time there is insufficient evidence to provide enough proof that cooling should be used routinely for patients with brain injury and, like all treatments, there can be some risks and side effects.

Study Progress: Patient recruitment commenced in 2010 and completed in November 2017.

  • 1st Interim Analysis (25% + 6 month follow-up) was Feb 2012. DSMC supported continuation of study.
  • 2nd Interim Analysis (50% + 6 month follow-up ) was March 2015

Endorsement: The POLAR Study was endorsed by the Australian and New Zealand Intensive Care Clinical Trials Group (ANZICS-CTG).

Funding: The POLAR Study was funded by the NHMRC and the Transport Accident Commission (TAC).

Trial Registration: ClinicalTrials.gov Identifier NCT00987688 and Australian and New Zealand Clinical Trials Registry Identifier ACTRN12609000764235

Contact: For further information about this study, please contact Tony Trapani, by email.


Current POLAR-RCT Protocol (3MB)

POLAR-RCT Protocol and Amendments (9MB)

DSMC Charter:



Cooper DJ, Nichol AD, Bailey M, Bernard S, Cameron PA, Pili-Floury S, Forbes A, Gantner D, Higgins AM, Huet O, Kasza J, Murray L, Newby L, Presneill JJ, Rashford S, Rosenfeld JV, Stephenson M, Vallance S, Varma D, Webb SAR, Trapani T, McArthur C; for the POLAR Trial Investigators and the ANZICS Clinical Trials Group. Effect of early sustained prophylactic hypothermia on neurologic outcomes among patients with severe traumatic brain injury: the POLAR randomized clinical trial [published online October 24, 2018].JAMA. doi:10.1001/jama.2018.17075. PMID: 30357266

Presneill J, Gantner D, Nichol A, McArthur C, Forbes A, Kasza J, Trapani T, Murray L, Bernard S, Cameron P, Capellier G, Huet O, Newby L, Rashford S, Rosenfeld JV, Smith T, Stephenson M, Varma D, Vallance S, Walker T, Webb S, Cooper DJ. Statistical analysis plan for the POLAR-RCT: The Prophylactic hypOthermia trial to Lessen trAumatic bRain injury-Randomised Controlled Trial. Trials 2018;19:259. PMID: 29703266

Nichol A, Gantner D, Presneill J, Murray L, Trapani T, Bernard S, Cameron P, Capellier G, Forbes A, McArthur C, Newby L, Rashford S, Rosenfeld JV, Smith T, Stephenson M, Varma D, Walker T, Webb S, Cooper DJ. Protocol for a multicentre randomised controlled trial of early and sustained prophylactic hypothermia in the management of traumatic brain injury. Crit Care Resusc 2015;17:92-100. PMID: 26017126

POLAR SAP Update. Uploaded 12 June 2018

POLAR SAP Update Correction: Figures 1 and 2 aligned with text from 12 June 2018. Uploaded 13 June 2018


POLAR-RCT Newsletters 2009-2010 (0.7MB)

POLAR-RCT Newsletters 2011-2012 (3.2MB)

POLAR-RCT Newsletters 2013-2014 (6.5MB)

POLAR-RCT Newsletters 2015-2016 (7.2MB)

POLAR-RCT Newsletters 2017 (3.9MB)