The reason to prewarm patients to to maintain a normothermic temperature which will, therefore, decrease the risk of post-op infections. One of the patient safety goals set by the IHI (Saving 100,000 Lives Campaign) was to decrease post-op infections - preop antibiotics, discontinuing them within 24 hours, maintaining normothermic temperature, etc. Research has shown that if a patient is prewarmed for at least 30 minutes preop, temperature is maintained throughout surgery and they continue to be warmed in PACU, the incidence of post-op infections are decreased. Leukocytes can not work properly in a cold environment so, therefore, keeping a patient's body temperature closer to normal will help to decrease their susceptibility to infection. It also helps to decrease cardiac events.
http://jama.ama-assn.org/cgi/content...?view=abstract
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract
http://www.bairpaws.com/arizanthealt..._warming.shtml
In our PACU we use the Bair Paws gowns and the patients love it. Also the staff isn't running for warmed blankets all the time. The warmed blankets only stay warm a couple of minutes and do not maintain a patient's body temp.