Ultrasound Guided Pecs Block and Ketamine Infusion for Preventing Chronic Pain in Patients Undergoing Breast Cancer Surgery

"Before skin incision, a bolus 0.35 mg/kg ketamine will be given followed by a continuous infusion 0.25 mg/kg/hr.~Ketamine infusion will be stopped 30 minutes before the end of the surgery"

Pecs block will be performed before surgical incision with the help of an ultrasound (US) by experienced anesthesiologist. The drug used for the pecs block will be two syringes of 10ml and 20 ml containing bupivacaine 0.25% (total 30 ml).

Intravenous Nalbuphine 0.1 mg/kg

Intravenous Paracetamol 1g or 15mg/kg (if weight is \< 50kg).