Early Prophylactic Hypothermia Doesn’t Improve TBI Outcomes
The effectiveness of early prophylactic hypothermia in improving long-term neurological outcomes in patients with severe traumatic brain injury (TBI) has been the subject of much debate for over thirty years. Not surprisingly given the challenges of conducting formalised studies in patients who experience sudden traumatic injury, many of the studies undertaken to date have failed to meet the standards necessary to draw definitive conclusions or have been limited by acknowledged potential publication bias.
The Prophylactic hypOthermia to Lessen traumatic bRain injury (POLAR) randomised controlled trial was designed by the Australian and New Zealand Intensive Care Society which included Prof Alistair Nichol, UCD Professor of Critical Care Medicine at St Vincent’s University Hospital while he was Associate Professor at the School of Public Health and Preventative Medicine at Monash University.
The Phase III trial took place across 6 countries over a ten year period recruiting 511 patients with severe traumatic brain injury from out-of-hospital and emergency department settings. The patients were randomised to early prophylactic hypothermia (33oC – 35oC) sustained for between 72 hours and up to 7 days if intracranial pressures were elevated with gradual rewarming or to controlled normothermia (37oC) for 7 days. The primary endpoint measure was favourable neurologic outcomes or independent living obtained by blinded assessors utilising a Extended Glasgow Outcome Scale (GOSE) score at 6 months after injury.
Among the 511 patients who were randomised, 500 provided ongoing consent and 466 completed the primary outcome evaluation. Favourable GOSE scores at 6 months occurred in 117 patients (48.8%) in the hypothermia group and 111 (49.1%) in the normothermia group. The study concluded that among patients with severe traumatic brain injury, early prophylactic hypothermia compared with normothermia did not improve neurological outcomes at 6 months. Hence these findings do not support the use of early prophylactic hypothermia for patients with severe traumatic brain injury.
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; POLAR Trial Investigators and the ANZICS Clinical Trials Group.
JAMA. 2018 Oct 24. doi: 10.1001/jama.2018.17075.