IHAST II and the response of neuroanaesthetists

Deliberate mild hypothermia was first used in 1955 as an intraoperative technique to ameliorate new neurological deficits following cerebral aneursym clipping, and subsequently was also used following neonatal asphyxia, head trauma and cardiac arrest. The Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST II) randomized control trial was designed to determine the effectiveness of mild hypothermia to decrease neurological deficits following aneurysm surgery. No overall benefit was demonstrated in the hypothermic group versus normothermic group (67% versus 63% good outcome; p=0.32), with a higher rate of bacteraemia in the hypothermic group (5% versus 3%; p=0.05). We undertook a survey of Australasian and Asian neuroanaesthetists to determine whether their thermal management of patients undergoing cerebral aneursym clipping had changed in response to the IHAST II trial results.