Effects of Active Prewarming in Perioperative Hypothermia in Adults

Inclusion Criteria: * \> 18 years old. * American Society of Anesthesiologists I-III. * Undergoing surgery under general or locoregional anesthesia lasting more than 30 minutes. * General surgery: hernias, cholecystectomies, hepatectomies, intestinal resections, pancreatoduodenectomies ... * Traumatology and orthopedics: total / partial knee prosthesis, total / partial hip prosthesis, osteosynthesis, removal of material, arthroscopies, hallux valgus, lumbar arthrodesis ... * Neurosurgery: lumbar arthrodesis, excision of intracranial tumors. * Gynecology: Hysterectomies, adnexectomies, hysteroscopy ... * Otorhinolaryngology: septoplasty, nasosinusal endoscopic surgery, tonsillectomies, adenoidectomies, thyroidectomies... * Thoracic: Pneumonectomies and pulmonary resections, sympathectomies, thoracoscopy ... * Urology: Bladder transurethral resection , prostate transurethral resection, nephrectomies. * Maxillofacial: parathyroidectomies, microsurgery ... * Ability to understand the study, give authorization and collaborate with data collection Exclusion Criteria: * Local anesthesia or peripheral nerve block. * Urgent or emergent surgery. * Cognitive impairment or lack of collaboration of any kind * Pregnant women undergoing cesarean section. * Diabetes Mellitus poorly controlled (HbA1c\> 6.5-7%) * Subjects that are under treatment with drugs that interfere with thermoregulation or may cause drug-induced hyperthermia (amphetamines, barbiturates, inhaled gases ...) * Subjects …