The effect of Ketamine infusion on post mastectomy pain syndrome: a randomized controlled study

Background: Acute postoperative pain after breast surgery is one of the major factors contributing to prolonged hospital stay.In addition persistent post mastectomy pain (PPMP) is rated as the most important cause of suffering in those patients. Objectives:The objectives of this study are to investigate the efficacy and safety of ketamine infusion on the incidence of acute postoperative and chronic post-mastectomy pain in female patients undergoing modified radical mastectomy.Patients and methods: 40 Patients were included in this study, divided into 2 groups (20 patients for each): Group 1 (G1): Control group in which patients received I.V. saline infusion before skin incision and for 24 hours after surgery.Group 2 (G2): In which patients received pre-emptive I.V bolus 0.5 mg / kg ketamine before skin incision followed by a continuous infusion of 0.25 mg / kg per hour for 24 hours post-operative.We measured hemodynamic variables, Visual Analogue Score at rest and movement of the limb or cough (VAS-R and VAS-M respectively) at zero line, 2, 4, 8, 12, 16, 24 hours postoperatively, time to the first request of analgesia, total morphine consumption, sedation score and development of side effects.LANSS (Leeds Assessment of Neuropathic Symptoms and Signs) score was assessed at 1, 2, 3, 6 months postoperatively.Results: There was a significant reduction in VAS-R and VAS-M (p<0.05),total morphine consumption (p<0.01) with significant delay in the 1st analgesic request (p<0.001) at all time points in ketamine group.LANSS score was significant reduced (p<0.05) in ketamine group compared to control group at all time points. Conclusion:Perioperative use of ketamine in patients undergoing modified radical mastectomy, reduced acute postoperative pain, morphine consumption and the development of chronic post mastectomy pain with no serious side effects.