Effect of trans-tracheal injection of local anaesthetic on the incidence of post-operative sore-throat in patients undergoing robotic assisted gynaecological surgeries under general anaesthesia - A Randomized control trial

Background and Aims:

Postoperative sore-throat (POST) is a major concern for patients undergoing any surgery under general anaesthesia. Patients undergoing robotic assisted gynaecological surgeries have much lesser surgical pain and shorter hospital stay when compared to patients undergoing open surgeries. But it is noticed that majority of these patients complain of sore-throat and hoarseness. This may be attributed to the steep Trendlenburg positioning used during the procedure which could lead to airway oedema. Methods to reduce the POST and hoarseness will allow faster postoperative recovery and better patient satisfaction. This study is performed to assess the effectiveness of single dose 5ml of trans-tracheal lignocaine 4% on the incidence of POST, hoarseness and cough in patients undergoing robotic assisted gynaecological surgeries under general anaesthesia.

Methods

This prospective, randomised, single blinded study will be conducted after obtaining approval from hospital ethical committee, clinical trial registry of India (CTRI)  and informed written consent from patients.  Patients aged 18–60 years, of the American Society of Anaesthesiologists (ASA) physical status 1-2 undergoing robotic assisted gynaecological surgeries lasting 2-3h under general anaesthesia with endotracheal tube will be included in this study. Patients with anticipated difficult airway, history of allergy to the test drug, who required more than one attempt  at intubation and those with pre-operative sore throat or already on analgesics or steroids (systemic or inhaled) will be excluded from the study.

The patients will be randomly assigned into two equal groups, L and S, based on computer-generated random sequence of numbers. Concealment will be achieved by closed envelope technique. Standard general anaesthesia protocol will be followed in both groups. Patients will receive oral ranitidine 150 mg, metoclopramide10 mg, and alprazolam 0.25 mg on the night before surgery and ranitidine 150 mg and metoclopramide 10 mg on the morning of

surgery. In the operation theatre, intravenous (IV) cannula will be inserted and monitoring with electrocardiography, noninvasive blood pressure monitor, and pulse‑oximeter will be done. Patients in group L will receive trans-tracheal injection of 5ml of 4% lignocaine and group P will receive trans-tracheal injection of 5ml of 0.9% saline.

 Patients will be preoxygenated with 100% O₂; glycopyrrolate 0.2 mg, midazolam 2 mg, and fentanyl 2 µg/kg will be given intravenously. They will then be induced with IV propofol 1.5–2.5 mg/kg till there is loss of response to verbal command and muscle relaxant atracurium will be given. Patient will be maintained on O₂, air and sevoflurane. If >1attempt will be required for intubation, the patients will be excluded from the study. The cuff pressure will be measured and will be set to 25 cmH2O using Portex cuff inflator (manufacturer: Smiths Medical International Ltd., UK) in both groups.

 Toward the end of surgery, IV ondansetron 4 mg and IV paracetamol 1 g will be given to all patients. Four hours after surgery all patients will receive oral paracetamol 650 mg 8th hourly. Patients will be given rescue analgesia with IV tramadol 1mg/kg if the patient complained of pain. The total dose of tramadol given in the first 24 h will be noted for both groups. Postoperative sore throat, cough and hoarseness will be monitored in the Intensive Care Unit (ICU) by the anaesthetist who will be blinded and the responses will be noted at 0, 2, 4, 12, and 24 h.

The patients will be asked to grade POST, cough, and hoarseness using a predefined category scale with scores 0–3. Total intra-operative as well as post-operative opioid consumptions will be documented.

Category scale score for assessment of sorethroat/hoarseness/cough

Grade Severity

0 No sore throat/hoarseness/cough

1 Minimal ‑ Patient answered in the affirmative when asked

2 Moderate ‑.Patient complained on her own

3 Severe ‑.Patient in obvious distress