Background: The NOL system (PMD-200™ Nociception Monitor; Medasense Ltd, Israel) is used for real-time detection of physiological nociception in anesthetized patients by assessing varia-bles indicative of sympathetic activity, such as photoplethysmography, skin conductance, pe-ripheral temperature, and accelerometry, which are quantified into a "NOL" index. This index is more sensitive than traditional clinical parameters in estimating pain and stress responses. While its effectiveness in general anesthesia is well-documented, its efficacy in epidural anes-thesia needs investigation.
Methods: This retrospective study analyzed NOL index dynamics compared to conventional pa-rameters after epidural administration of a local anesthetic during abdominal surgeries. After Ethics Committee approval and DRKS registration, 119 NOL measurements were retrospectively analyzed following thoracic epidural catheter administration. NOL values were assessed at 0, 1, 3, and 5 minutes post-application and compared to heart rate, blood pressure, and bispectral in-dex dynamics.
Results: This studys showed a significant decrease in NOL values post-local anesthetic admin-istration, unlike classical clinical parameters. Higher doses of local anesthetics led to a signifi-cant, dose-dependent decrease in NOL index.
Conclusions: This study is the first to demonstrate the NOL-Index's effectiveness in assessing nociceptive effects post-epidural administration, showing its superiority over conventional pa-rameters and sensitivity to dose variations.