NOL Index in Response to Pacemaker Stimulation

The Nociception Level Index (NOL Index) utilizes various signals to assess the balance of nociception and antinociception during anesthesia. Its correlation with nociceptive stimuli and opioids is known, but its response to isolated heart rate changes remains uncertain. The aim is to investigate how cardiac pacing affects the NOL Index.

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Key information

Conditions

Nociceptive Pain Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

"Prof CC Iliescu" Emergency Institue for Cardiovascular Diseases

Bucharest, 022328, Romania

About this study

The Nociception Level Index (NOL Index) represents an innovative approach to monitoring nociception during general anesthesia, utilizing a combination of signals from photoplethysmography, accelerometry, thermometry, and skin conductance to assess the balance between nociceptive and antinociceptive states. Research has already established how the NOL Index correlates with both nociceptive stimuli and opioid levels, providing valuable insights into patient responses. However, the impact of changes in heart rate, specifically through isolated cardiac pacing, on the NOL Index is not yet clear. The primary goal of this study is to explore and understand how cardiac pacing might influence the readings of the NOL Index, potentially offering a new dimension to managing anesthesia effectively.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Informed consent
Preoperative and postoperative sinus rhythm (50-90 bpm)
Norepinephrine support < 100 ng/kg/min

Exclusion criteria

Redo or emergent surgery
History of any cardiac arrhythmia
Any cardiocirculatory support other than norepinephrine
Perioperative treatment with beta-blockers, calcium-channel blockers or ivabradine

Treatment and study plan

Pacemaker stimulation

Procedure

We deactivate the pacemaker to establish baseline measurements of NOL, bispectral index (BIS), mean arterial pressure (MAP), and heart rate (HR), recorded every minute for 5 minutes. We then adjust the pacemaker to 90 bpm and 110 bpm in subsequent 5-minute phases to assess the physiological responses. After deactivating the pacemaker to analyze washout effects, we reactivate it at 110 bpm to observe any changes. A temporary disconnection of the NOL monitor for 1 minute tests system reliability, followed by continued monitoring at the same rate for an additional 5 minutes. Each measurement phase averages data from the last 10 seconds each minute to ensure accuracy and reduce artifacts.

Primary outcomes

NOL index

Time frame: Every minute during seven 5-minute intervals under various pacemaker settings, totaling 35 minutes of monitoring.

The Nociception Level Index (NOL Index) quantitatively evaluates the balance between nociception and antinociception in mechanically ventilated postoperative adult patients after elective cardiac surgery, utilizing a multiparametric approach that includes photoplethysmography, accelerometry, thermometry, and skin conductance.

Sponsors and collaborators

Lead sponsor

Institutul de Urgenţă pentru Boli Cardiovasculare Prof.Dr. C.C. Iliescu

Other

Registry information

Official study title

NOL Index in Response to Pacemaker Stimulation in Open-heart Surgery

Important dates

Study start: 2024
Primary completion: 2025
Study completion: 2025
First posted: Nov 20, 2024
Registry last updated: Aug 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed