Efficacy and Safety of Ketamine Added to Local Anesthetic in Modified Pectoral Block for Management of Postoperative Pain in Patients Undergoing Modified Radical Mastectomy

This randomized Clinical trial was approved by the ethics committee of South Egypt Cancer Institute, Assuit University, Assuit, Egypt. Sixty patients aged 18 - 60 years, American Society of Anesthesiologists (ASA) class I-II, with body weight of 50 - 90 kg and arranged for modified radical mastectomy) were enrolled in this study. Patients with a history of bleeding diathesis, relevant drug allergy, opioid dependence, morbid obesity, sepsis, prior surgery in the supraclavicular, infraclavicular or axillary regions, alcohol or drug abuse and those with psychiatric illnesses that would interfere with perception and assessment of pain were excluded from the study.

Preoperatively, patients were taught how to evaluate their own pain intensity using the Visual Analog Scale (VAS), scored from 0-10 (where 0= no pain and 10=worst pain imaginable), and whenever (during the follow up period) VAS points to a value ≥ 3. Analgesia comprised PCA with an initial morphine bolus of 0.1mg/kg once pain expressed by the patient or if VAS ≥ 3 followed by 1mg boluses with a lockout period a 5 minute. The time to first request for analgesia and the total analgesic consumption in the first 24 hours were recorded.

On arrival to the operating room, an intravenous line was inserted. Monitoring included electrocardiography (ECG), non-invasive blood pressure (NIBP), arterial oxygen saturation (Sao2) and end-tidal carbon- dioxide were applied.

Anesthesia was induced for all participating patients with 2 μg/kg fentanyl, 2-3 mg/kg propofol and 1.5 mg/kg lidocaine. Endotracheal intubation was facilitated by 0.15 mg/kg cis-atracurium. Anesthesia was maintained by 1-1.5 MAC isoflurane in 50% oxygen / air mixture and 0.03 mg/kg cisatrcurium respectively in ventilation parameters to maintain on ETco2 of approximately 35- 40 mmHg. Ultrasound guided pecs block then performed

Patients were randomly assigned into 2 groups (using a randomization-computer program), 30 patients in each: