Total thyroidectomy triggers a systemic surgical stress response involving neuroendocrine and inflammatory pathways. Ultrasound-guided bilateral intermediate cervical plexus block (BICPB) is commonly utilized for postoperative analgesia; however, its specific impact on modulating the systemic stress biomarker response remains to be fully elucidated.

To evaluate the effect of an ultrasound-guided BICPB on the perioperative surgical stress response by comparing changes in specific serum inflammatory and metabolic biomarkers between patients receiving BICPB and those receiving total intravenous anesthesia (TIVA) alone.

In this prospective, randomized, controlled study, a total of 48 eligible patients scheduled for elective total thyroidectomy will be randomly assigned to two groups of 24 participants each:

• BICPB Group: TIVA combined with an ultrasound-guided bilateral intermediate cervical plexus block.
• Control Group: TIVA alone.

Venous blood samples will be collected at predefined intervals: preoperatively (baseline), immediately postoperatively, 24 hours and 48 hours post-surgery.

It is hypothesized that integrating an ultrasound-guided bilateral intermediate cervical plexus block with total intravenous anesthesia (TIVA) will significantly attenuate the surgical stress response, as evidenced by a reduction in specific serum biomarker concentrations (interleukin-6, C-reactive protein, total leukocyte count,cortisol, alpha-amylase, and glucose), compared to utilizing TIVA alone during total thyroidectomy.

Testing this hypothesis aims to provide scientific evidence regarding the routine integration of the bilateral intermediate cervical plexus block into standard anesthetic protocols for total thyroidectomy, with the objective of evaluating its potential to minimize perioperative stress and support postoperative patient recovery.