Elderly patients with hip fracture are frail due to associated comorbidity. In these situations, regional anesthesia is recommended as it is associated to less postoperative cognitive dysfunction. However, hypotension during the process may impair ischemic cardiopathy and induce a cerebrovascular stroke. Selection of the right anesthetic agent and the administration of vasoactive drugs during the process can minimize these risks. Although bupivacaine and levobupivacaine share pharmacokinetic and pharmacodynamic properties, the studies show conflicting results. The aim of this study is to investigate if there are clinically relevant differences between these two drugs in terms of hemodynamic parameters during the surgical process with special focus on the effects on regional cerebral oximetry and cognitive status after surgery.

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