1. General Surgery Service, Department of Surgery, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-970 Campinas, SP, Brazil
2. Head and Neck Service, Department of Surgery, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-970 Campinas, SP, Brazil
3. Anesthesiology Service, Department of Anesthesiology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-970 Campinas, SP, Brazil