Ultrasound Guided Pectoral Nerve I and II Blocks in Multimodal Analgesia for Breast Surgery: A Randomized Single Blinded Control Trial

All patients in the study group and their relatives/attendants will be informed about the drugs, Pecs block and research methodology by the principal investigator during the pre-anaesthetic check up, in the evening before surgery. Informed and written consent will be obtained from the patient and/or his/her relatives. In order to assess pain, patient will be familiarized about the use of Numerical Rating Scale (NRS), in a language they can understand. (0 "as no pain at all" to 10 as "worst pain in life"). All of the patients will be premedicated with Tab diazepam 0.2mg/kg (not exceeding 10mg ) given orally night before surgery and in the morning of surgery.

On the day of surgery, after the patient arrives in the patient holding area in the operation theater, peripheral venous assess will be secured with 18G I.V cannula. In the operating room standard monitoring device will be attached to monitor Electrocardiograph ( ECG) , Pulse- oxymetry ( SpO2) , Non-invasive blood pressure ( NIBP), heart rate (HR) and End-tidal CO2 (Capnograph).

All patients will receive a standardized general anesthetic with multimodal analgesia. Preoxygenation will be done with 100% oxygen for three minutes. Induction will be done with loading dose of intravenous Fentanyl 1.5 mcg/kg and Propofol 1- 2 mg/kg and vecuronium 100mcg/kg. Airway will be secured by endotracheal intubation.

After induction of general anesthesia and before the start of surgery,ultrasound guided Pecs block will be performed by using 20-G Tuohy needle under all asceptic precautions. Images will be obtained using a Sonosite ultrasound machine. The probe will be placed at the mid clavicular level and angled inferolaterally,and then the axillary artery and vein will be located. The probe will then be moved laterally until pectoralis minor and serratus anterior are identified. The needle will be advanced in the tissue plane between Pectoralis major muscle (PMm) and Pectoralis minor muscle (Pmm) at the vicinity of pectoral branch of acromiothoracic artery and 10 ml of 0.25 % Ropivacine will be deposited. Similarly, 20ml of 0.25% Ropivacaine will be infiltrated in between Pmm and serratus anterior muscle at the level of third rib. (Blanco, R., Fajardo, M., Parras, M.T. 2006) Anesthesia will be maintained with isoflurane, oxygen, additional vecuronium and fentanyl. We will monitor Blood pressure, heart rate, SpO2, EtCO2, and ECG intraoperatively. During intraoperative period, 1gm of intravenous paracetomol will be given 15 minutes before the completion of surgery, over 15 minutes. Ondensatron (4mg IV) will be administered 15 minutes before the end of surgery as a prophylaxis for postoperative nausea and vomiting. Any episode of intraoperative hypotension (MAP lower than 65 mmHg) and bradycardia (heart rate < 50 bpm) will be treated with ephedrine 5 mg and atropine 0.4 mg IV respectively. On the completion of surgery,neuromuscular blockade will be reversed with 0.05 mg/kg of Neostigmine and 10mcg/kg of glycopyrrolate. The patient will then be extubated and transferred to postoperative recovery room.

In the postoperative recovery unit, blood pressure, pulse rate and oxygen saturation will be monitored for two hours. Assesment of pain scores at rest, coughing and on shoulder abuction along with postoperative nausea and vomiting (PONV) will be done in the postoperative recovery unit mmediately after patient will be transferred. If the patient has NRS of >3/10 at rest, intravenous morphine 2mg will be administered. If the pain is still not controlled, additional morphine of 2 mg can be given at 10 minute interval. PONV will be assessed by a categorical scale from 0 to 2. Intravenous ondensatron 4mg will be given if PONV scale is ≥1. If this proves to be ineffective, metoclopramide 10 mg will be administered. This rescue analgesia and antiemetic regimen will be followed for next 24 hours of surgery.