The aim of this study is to evaluate the effect of using the non-invasive Conox monitor on intraoperative opioid consumption. Additionally, the study aims to assess the impact of Conox monitoring on recovery time, postoperative agitation rate, and pain scores, and to investigate the correlation between qCON and qNOX values and conventional hemodynamic parameters.

In recent years, both nationally and internationally, strategies aimed at minimizing perioperative opioid use and protocols designed to enhance postoperative recovery have gained increasing importance in anesthesia practice. The primary objectives of these developments are to improve patient care, minimize undesirable events, promote earlier discharge, and prevent long-term adverse outcomes .

Although opioids play an essential role in multimodal perioperative analgesia due to their proven efficacy, safety, and titratability, it is important to use the lowest effective opioid dose possible.

In thyroid surgery, neuromuscular blocking agents are not used after induction. Maintenance of anesthesia is achieved with inhalational anesthetic agents and opioids. Therefore, adequate titration of anesthetic depth directly affects postoperative comfort, drug consumption, and overall recovery .

The Conox monitor is a non-invasive, EEG-based monitoring device that simultaneously provides hypnosis (qCON) and analgesia/nociception (qNOX) indices. The current anesthesia depth monitoring devices used in our anesthesia unit allow monitoring of anesthetic depth only. However, nociception is one of the critical components of anesthesia. Nociception is defined as the patient's ability to respond to painful stimuli in relation to the effectiveness of administered analgesic agents. Proper management of painful stimuli during surgery enhances patient safety and allows optimal drug dosing.

By reducing unnecessary drug administration, postoperative complications may decrease and recovery can be positively influenced. The Conox monitoring system, based on EEG signals, offers the opportunity to monitor both anesthetic depth and nociception simultaneously . Combined monitoring of anesthetic depth and nociception provides anesthesiologists with a safer, more sensitive, and comprehensive monitoring approach, thereby improving the quality of patient care.

This study aims to investigate whether Conox monitoring provides clinical advantages compared with routine physiological parameter monitoring.

Inclusion Criteria:

• Patients aged 18-70 years
• Thyroidectomy cases with ASA physical status I-II
• Patients who have provided written informed consent

Exclusion Criteria:

• Skin lesions preventing EEG electrode placement
• Neurological disorders (e.g., epilepsy)
• Anticipated difficult airway

Individual participant data (IPD) will not be shared due to institutional regulations and ethical considerations. The study will be conducted at a single center, and data sharing was not included in the informed consent process.