The Bair Hugger system is a convective temperature management system often utilized within a hospital or surgery center to maintain a patient's core body temperature . The Bair Hugger system consists of a reusable warming unit and a single-use disposable warming blankets for use before, during and after surgery. This medical device launched in 1987 and is currently manufactured by the 3M Company . 
The Bair Hugger system uses convective warming, also known as forced-air warming, to prevent and treat perioperative hypothermia , defined as a core body temperature less than 36.0 degrees Celsius (96.8 degrees Fahrenheit), in surgical patients. Unintended hypothermia has been associated with numerous negative outcomes in surgical patients, including increased rate of surgical site infection, increased blood loss, and higher mortality rate.
The system includes two primary components: a warming unit and a disposable blanket. The warming unit is connected by a flexible hose to the single-use blanket. Warm air from the warming unit passes through the flexible hose and into the blanket. Once the warmed air reaches the blanket it exits through a series of micro-perforations on the underside of the blanket, warming the patient's skin in an area not involved in the surgical procedure. 
The Bair Hugger system warms effectively due to the properties of convection and radiation ; heat transfer improves with the movement of warmed air across the surface of the patient's skin. Up to 64 percent of the patient's body surface may be recruited for heat transfer, depending on which Bair Hugger blanket is utilized.
The Bair Hugger system received FDA clearance in 1987.  Today, the system features 25 blanket models  and globally has warmed more than 200 million patients.  The Bair Hugger system is the most utilized patient warming modality in the U.S. and is currently used by more that 80 percent of U.S. hospitals.