Analgesic Efficacy of Inter Pleural Ropivacaine Road in Post Thoracotomy Pain for Oncologic Surgery

"ropivacaine at 7.5 mg/ml: 4 ml + 4 ml of saline solution to obtain 8 ml of a ropivacaine solution at 3.75 mg/ml injected into the intrapleural catheter every 6 hours.~Treatment administration = every 6 hours for 48 hours."

8 ml of saline solution will be injected into the intrapleural catheter. Treatment administration = every 6 hours for 48 hours.