Medications used to put people to sleep during surgical procedures also cause changes in the body's ability to control its temperature. These changes can make a person's temperature drop below normal. To minimize this drop in body temperature, different types of body warming products are used during surgery. This study is designed to compare the the temperatures of people under general anesthesia after 60 minutes of warming with each product. The study hypothesis is that the people warmed with the Dynatherm Medical vitalHEAT vH2 System will decrease less in the first 60 minutes of warming time than people warmed with the Arizant Bair Hugger System.