IRCT20260708070098N1 IRCT 2026-07-20 Tehran University of Medical Sciences Post thoracotomy pain management Comparing the effect of epidural catheter with ketamine drip in analgesia after elective thoracotomies 2026-08-23 anticipated 72 Pending https://irct.ir/trial/91534 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Randomization will be performed using the random permutation block method. In this method, the block sizes are 4 and 2 (in random order) and the allocation ratio is 1:1. In this way, an equal number of each treatment will be provided in each block. The random sequence will be generated by the methodologist using the sealedenvelope.com software. The random allocation list of the clusters will be available only to the design methodologist. In order to conceal the randomization process, 72 paper labels will be written with random 10-digit codes without a specific order and frame, which will be the identification number of the relevant treatment, and only the design methodologist will be aware of the relevant code. The labels will be attached to the drug packages in the order of the randomization list. The drug packages will be arranged in a box in the order of the randomization list. When the physician declares a patient eligible, the design methodologist will provide the patient with the treatment package. The design methodologist will be excluded from the rest of the study processes, Blinding description: The study is single-blind. The drugs used in the two groups are prepared in identical containers without name labels, in the same color and smell, and are coded. They are provided to both groups based on random allocation by the project partner, so none of the patients are aware of the treatment assigned and will not be informed until the end of the study. 2 Thoracotomy. Intervention 1: Intervention group: In this group, after induction of anesthesia before the first incision, 0.3 mg/kg intravenous ketamine is administered as a bolus, followed by intravenous infusion at a rate of 0.3 mg/kg/hour for patients. In case of postoperative pain (VAS score > 4), 2.5 mg of intravenous morphine is injected and its frequency is recorded. Intervention 2: Control group: In this group, at the end of the operation, epidural infusion of 0.2% ropivacaine is started in all patients at an infusion rate of 10 cc/hour. In case of postoperative pain (VAS score > 4), 2.5 mg of intravenous morphine is injected and its frequency is recorded. No - There is not a plan to make this available Justification or reason for not sharing IPD is -