Comparison of Nociception Monitoring in Sedated ICU Patients: Behavioral Scale vs. Nociception Level (NOL) Monitor

Abstract

Introduction

Pain is a complex, personal experience that is difficult to assess, especially in critical care patients who are unable to communicate. Traditional tools for measuring pain in these patients rely on behavioral observation, such as the Critical Care Pain Observation Tool (CPOT), but these tools have limitations in individuals under deep sedation. Based on non-invasive physiological parameters, Nociception Level (NOL) system emerges as a technological alternative for measuring nociception in clinical settings. This study aimed to compare the effectiveness of the NOL monitor with a behavioral scale (CPOT) in response to nociceptive stimuli in deeply sedated ICU patients.

Methods

This quasi-experimental study included 15 patients in a general ICU between January 2023 and May 2024. Behavioral (CPOT) and physiological (NOL) responses to nociceptive stimuli (pressure on nail beds and endotracheal suctioning) were compared. Measurements were taken before, and at five time points after the stimuli (0, 15, 30, 60, and 90 seconds). Patients with conditions that could alter nociception measurements, such as arrhythmias or neuromuscular blockades, were excluded.

Results

Significant differences were observed between CPOT and NOL scores for both nociceptive stimuli. The NOL system captured sustained nociceptive responses more effectively than the CPOT scale, particularly after endotracheal suctioning, where the CPOT stopped detecting pain after 60 seconds, while NOL continued to show elevated values.

Conclusion

The NOL monitor is a promising tool for assessing pain in deeply sedated ICU patients.