A Randomized Comparative Double Blinded Study of Postoperative Analgesic efficacy of 0.25 percent ropivacaine with Dexmedetomidine versus 0.25 percent ropivacaine with dexamethasone in ultrasound guided bilateral superficial cervical plexus block for thyroidectomy patients

Thyroidectomy is associated with moderate incisional pain, burning sensation, uneasiness in swallowing and post-operative nausea vomiting (PONV) attributable to endotracheal intubation, tissue dissection, and hyperextension during surgery.

Cervical plexus blocks can be performed in patients undergoing thyroid surgery and prolonged postoperative analgesia can be provided by administering local anaesthetic solutions with or without adjuvant. It has been reported that up to 90% of patients require narcotic analgesics during the first postoperative day.

BSCPB is a procedure with a low serious complication rate. The risks of phrenic nerve palsy and total spinal anaesthesia from injection into a dural cuff are restricted to blockade of the deep cervical plexus only; diffusion of local anaesthetic is not sufficient to account for these phenomena with a superficial technique

Local anaesthetics, when used alone, offer a short duration of analgesia. Therefore, various adjuvants have been studied, including dexmedetomidine, an α2 agonist, which provides stable haemodynamics, and prolonged analgesia with minimal side effects and Dexamethasone, a corticosteroid, is a recent addition to the list with promising results in BSCPB.

We will be investigating the effects of dexmedetomidine and dexamethasone as adjuvants with ropivacaine on the duration of analgesia as a primary outcome and NRS, rescue analgesic requirement, haemodynamic parameters, PONV, and adverse events as secondary outcomes in BSCPB for thyroidectomy under general anaesthesia

Patients of ASA I and II of either sex posted for elective thyroidectomy under general anesthesia, will be randomly assigned to each group (A and B). After obtaining written informed consent, participants will be randomized to receive bilateral SCPB with Group A will be receiving ropivacaine 0.25% with dexmedetomidine 1mcg/kg and Group B will be receiving ropivacaine 0.25% with dexamethasone 0.05mg/kg 1ml.

To reduce subjective and objective bias, the study will be double-blinded so that the anaesthesiologist doing the procedure, the patient, and the monitoring personnel will be not aware of group allocation i.e., the mixture used for the BSCPB. The syringe will be labelled with a number, and a record of the syringe’s contents will be preserved.

Patients in this trial will be evaluated by taking detailed history, airway assessment, and routine investigations along with thyroid function tests. All standard ASA monitors connected and baseline vitals will be recorded. Patients will be given intravenous midazolam 0.02 mg/kg and fentanyl 2µg/kg as premedication along with preoxygenation with 100% oxygen. Propofol 2 mg/kg and vecuronium 0.1 mg/kg will be used for inducing general anaesthesia, which will be followed by tracheal intubation. Anaesthesia will be maintained with inhalational agent sevoflurane (MAC 0.7–1.3) in a mixture of O2 :N2 O in a ratio of 50:50.

The block is normally performed in supine position with the patients head turned to the contra-lateral side. Once the skin is cleaned and prepared with antiseptic, the transducer is placed over the lateral side of the neck at the midpoint of the posterior border of the sternocleidomastoid muscle (SCM).The patients will undergo ultrasound evaluation with SONOSITE (linear probe- 5-12 MHz). The transducer is positioned such that the tapering end (posterior border on the ultrasound image) of the SCM is in the centre of the screen . The needle is then introduced from the posterior aspect through the skin and platysma and 5-10 ml of LA deposited just behind this landmark. This will involve two injections, starting from mid-point of SCM, one from caudal to cranial end and the second one from cranial to caudal end.

Duration of Postoperative analgesia: The time between the onset of block and the first rescue analgesia i.e., NRS more than or equal to 4.

Rescue Analgesia: Injection Tramadol 1mg/kg.

Side effects- PONV, Shivering will be assessed.

Sedation score is assessed by Modified Ramsay Sedation score