Introduction: Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Prophylactic hypothermia is effective in laboratory models, but clinical studies to date have been inconclusive, partly because of methodological limitations. Our Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury (POLAR) randomised controlled trial is currently underway comparing early, sustained hypothermia versus standard care in patients with severe TBI. We describe our study protocol and the challenges in conducting prophylactic hypothermia research in TBI.
Design: We aim to randomise 500 patients to either prophylactic 33°C hypothermia initiated within 3 hours of injury and continued for at least 72 hours, or standard normothermic management. Patients will be enrolled by paramedic services in the prehospital setting, or by emergency department staff at participating sites in Australia, New Zealand and Europe. The primary outcome will be the eight-level extended Glasgow outcome scale (GOSE), dichotomised to favourable and unfavourable outcomes at 6 months after injury. Secondary outcomes will include mortality at hospital discharge and at 6 months, ordinal analyses of 6-month GOSE outcomes, quality of life with health economic evaluations and the differential proportion of adverse events. We will predefine subgroup and interaction analyses.
Discussion: After a run-in phase, recruitment for our main study began in December 2010. When the study is completed, we aim to provide evidence on the efficacy of prophylactic hypothermia in TBI to guide clinicians in their management of this devastating condition.