Comparison of effects of intraoperative infusion of low dose ketamine versus lignocaine in post operative pain management in patients undergoing breast cancer surgery.

Breastcancer surgery is a common surgery with many of the patients experiencingmoderate to severe pain, both acute and chronic postsurgical pain in the postoperative period. One of the modalities formanagement of postsurgical pain in breast cancer surgery is opioids but increasing no of recent reports regarding early reccurence of ma;ignancy with opioid usage is alarming. Opioidsare also associated with several adverse effects such as itching, postoperativenausea and vomiting, respiratory depression, etc. Concerns about opioid risk inthe postoperative period has aroused an increased interest in the use ofnon-opioid analgesic adjuvants. Intravenous lignocaine and low dose ketamineinfusions have individually shown to reduce the opioid consumption and toimprove the overall postoperative outcomes in several studies. There is apaucity of literature comparing the efficacy of these two drugs. So, we did thisstudy to compare the efficacy and duration of analgesia  and development of chronic pain with use of intravenouslignocaine and low dose ketamine in breast cancer surgery. This will help usfind out a superior technique with effective analgesia that will be veryhelpful to control pain and prevent its complication in many of the patientsundergoing breast surgery.

Study was conducted on 60 patients undergoingmastectomy after getting approval from Ethical committee and consent. Patients were randomised to two groups of 30 each. Preoperatively, all patients were instructed regardinghow to read the Numerical Rating Scale used for assessingthe pain in the postoperative period. Premedication was with oral ranitidine150 mg and metoclopramide 10 mg on the previous night of surgery and on themorning of surgery.

On arrival to the operation theatre, standard monitors were attached and baseline parameters wererecorded. Each patient received iv glycopyrrolate 10 mcg/kg, iv ondansetron 0.1mg/kg, iv midazolam 0.01mg/kg and iv fentanyl 2 mcg/kg. After pre-oxygenation for three minutes, patients wereinduced with Inj. Propofol 2mg/kg. Endotracheal intubation with appropriatesized, cuffed endotracheal tube was facilitated with Inj. Succinylcholine 1.5mg/kg. Anesthesia was maintained with nitrous oxide, oxygen and Isoflurane and Inj.Vecuronium bromide 0.1 mg/kg bolus for muscle relaxation. Additional doses ofvecuronium were given as deemed necessary by the attending anesthesiologist.

Group K received anintravenous bolus of ketamine 0.2 mg/kg before skin incision followed by 0.2mg/kg/hour until the end of the procedureand group L received an intravenous bolus dose of preservative free2% lignocaine 2 mg/kg before skin incision followed by 2 mg/kg/hour till theend of the procedure. Intra-operatively, patient’s vital signs were recordedperiodically and patients having fluctuations in HR and MAP >30% of baselinevalue were treated accordingly. After the completion of the procedure, all infusionswere stopped and the patient reversed with  Neostigmine  and  Glycopyrrolate and extubated. The time for extubation and the time forresponse to oral commands were recorded.

After the procedure, patients were monitored in therecovery room and in the post-operative ward. Any perioperative complicationssuch as tachycardia, bradycardia, hypertension, hypotension, nausea, vomiting,muscle twitching, seizures, respiratory depression were watched for.Numerical Rating Scale  for pain were assessed serially at 10minutes, 30 minutes, 1 hour, 4 hours, 12 hours and 24 hours after surgery. Inj.Paracetamol 1 gram iv and inj. Tramadol 50 mg iv were given as the first lineand second line rescue analgesics respectively and were administered if NRS ≥4. The time for first analgesic request was recorded. The duration of analgesiawas taken as the time at which patient complained of pain or the NRS was ≥ 4on assessment at serial intervals. The total dose of rescue analgesics neededin the first 24 hours were also recorded. Postoperatively, sedation was assessed soon afterextubation and after 30 minutes by using modifiedRamsay sedation score. Development of chronic postsurgical pain was assessed by telephonic enquiry of all patients after 3 months of surgery.