The Effect of Preprocedural Subanesthetic Ketamine on Pain and Anxiety

Inclusion Criteria: * Patients who underwent elective thoracic surgery via thoracotomy * Patients with ASA physical status I-III Exclusion Criteria: * Describing chronic pain, * Have a bleeding disorder, * Having a history of analgesia drug use, * Have a history of liver disease, * Have serious metabolic and endocrine problems, * Have a history of allergy to ketamine and local anesthetics, * Have an infection in the intervention area, * Rejecting thoracic epidural catheter, * Describing acute pain in any part of the body during the preoperative evaluation, * Thoracic epidural catheter duration greater than five minutes (time from needle entry to catheter placement) * Patients requiring more than two Tuohy injection attempts