Inclusion Criteria:  All patients aged between 15 and 65 years, admitted to the central operating room of the hospital for maxillofacial surgery.  Exclusion Criteria:  Known or suspected coronary artery disease on preoperative consultation; Unstable arterial hypertension Insulin-dependent diabetes Second degree atrioventricular block Neuro-vegetative dysautonomia; known allergy or intolerance to a drug of the protocols