Intraoperative Nociception Monitoring Using the NoL Index: Phase-Specific Assessment of Nociceptive Responses During...

Area of Science:

• Anesthesiology
• Surgical Monitoring
• Pain Management

Background:

• Intraoperative nociceptive responses under general anesthesia are challenging to quantify, especially during spinal surgery.
• The Nociception Level (NoL) index is a multiparametric tool assessing nociception and analgesia balance in anesthetized patients.

Purpose of the Study:

• To evaluate Nociception Level (NoL) index fluctuations during specific spinal surgery phases.
• To assess the relationship between NoL values and intraoperative anesthetic administration (remifentanil and propofol).

Main Methods:

• Prospective observational study of 44 adult patients undergoing spinal surgery under remifentanil-propofol anesthesia.
• Continuous NoL monitoring using the PMD100™ system across 16 defined surgical phases.
• Analysis of mean NoL values per phase and correlation with anesthetic infusion rates.

Main Results:

• Mean NoL values generally stayed within the target range (10-25).
• Significant NoL elevations (mean >27) occurred during pedicle screw insertion, cage insertion, and flavectomy.
• Lowest NoL values were observed during skin closure and discectomy phases.

Conclusions:

• Distinct nociceptive peaks were identified during specific spinal surgery stages despite standardized anesthesia.
• NoL monitoring can potentially identify high-nociception phases, aiding in tailored analgesic strategies.
• Further randomized trials are needed to confirm if NoL-guided anesthesia improves outcomes.