NICE published 'Inadvertent perioperative hypothermia' (NICE clinical guideline 65) in April 2008, which recommends that each patient undergoing anaesthesia should be assessed for risk of inadvertent perioperative hypothermia and forced air warming used where indicated to keep patients warm. The medical technology guidance does not supersede the guideline recommendations on pre- or perioperative warming. It also does not update the guideline with respect to the recommendation about forced air warming as a cost-effective use of resources. However, it does, for this product, update the recommendation for further research on the use of different warming devices. When considering new investment in warming devices, consideration should be given to whether use of the Inditherm patient warming mattress would be beneficial.