Effects of Bupivacaine and Levobupivacaine on Cerebral Oxygenation During Intrathecal Anesthesia in Elderly Patients

Inclusion Criteria: 1. Patients older than 70 years old who undergo major surgery for hip fracture and will receive intrathecal anesthesia 2. Patients in which it is considered adequate, according to the usual clinical practice, the use of bupivacaine or levobupivacaine as part of the intrathecal anesthesia 3. Patients who give their informed consent to participate in the study Exclusion Criteria: 1. Patients allergic to anesthetic drugs to be used in the protocol or to local anesthetics amida type. 2. Patients with severe aortic stenosis or hemodynamic instability. 3. Patients who refuse the anesthetic technique or contraindication for the use of the intrathecal technique. 4. Patients with severe cognitive impairment previous to the intervention (defined by a score in the Pfeiffer test of 8-10 errors) 5. Patients in which the use of bupivacaine or levobupivacaine is contraindicated as part of the intrathecal anesthesia 6. Any condition that, in the investigator's opinion, could pose a risk to the patient