Comparison of the Surgical Pleth Index and the Nociception Level Index in the Pediatric Population (NOLvsSPI)

Comparison of the Surgical Pleth Index and the Nociception Level Index in the Pediatric Population: An Observational Study

This observational study aims to compare two nociception monitoring methods. The Nociception Level (NOL) index and the Surgical Pleth Index (SPI) in the pediatric population during general anesthesia. While both monitors are designed to assess nociceptive responses through autonomic nervous system activity, they differ in methodology and parameters measured. The NOL index integrates multiple physiological signals using a self-learning algorithm, while SPI focuses on heart rate variability and plethysmographic amplitude. Although both have been studied individually in children, a direct comparison has not yet been conducted. This study will evaluate and compare each monitor's ability to detect and quantify nociceptive stimuli (surgical and tetanic) in children.

The investigators hypothesize that the NOL monitor and SPI monitor will both be able to quantify surgical stimuli and tetanic stimuli with monitors response to surgical stimuli > monitors response to tetanic stimuli. However, the investigators also hypothesize that the NOL index will do this superiorly, as it utilizes a self-learning algorithm and more parameters are incorporated in its algorithm

Study Overview

• Status: Recruiting
• Conditions: Pediatric Anesthesia; Anesthesia; Nociceptive Pain; Nociception Monitoring
• Intervention / Treatment: Device: Connecting all patients to the nociception level index(NOL) and the surgical pleth index (SPI); Device: All patient will receive a tetanic stimuli (60mA, 100hz) of 5 seconds before start of incision

Detailed Description

This is a single centre, observational prospective non-interventional study. The study will take place at the Radboudumc. After obtaining informed consent participants will be enrolled. Each participant will be treated according to the standard Radboudumc anaesthesia protocol with heartrate monitoring, respiratory rate monitoring, neuromuscular monitoring (TOF-Watch SX ) , intermittent non-invasive blood pressure monitoring and Bispectral index monitoring. Participants will be connected to the NOL index PMD-200 device using the finger probe and the SPI device (Carescape b650) using the pulse oxymeter directly after induction of anesthesia with propofol/sevoflurane. Before start of surgery, after recording a period of 30 seconds with no stimulation (no nociception) a standardised tetanic stimulus of 5 seconds with 60 mA and 100hz will be applied with the neuromuscular monitor on the patients ulnary nerve trajectory with two adhesive electrodes. This is a stimulus that is part of common anesthesiology practice in order to assess the patients neuromuscular blockade. Previous research has used tetanic stimuli of similar intensity as standardised nociceptive stimuli in order to validate nociception monitors. After SPI and NOL monitor values return to baseline (pre-tetanic stimulus value) surgery with first incision will commence.

During the operation the response to the standardised stimuli and nociceptive events such as intubation, insertion of supraglottic airway, surgical incision and administration of opioids will be registered by a trained researcher. After surgery, upon discharge to the anaesthesia recovery room, patients will be disconnected from both monitors. Post-operative pain/comfort scores and post-operative analgesia usage will be registered by the researcher at the recovery room. Total duration of the study inclusion period is expected to be 1 year.

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

• Study Contact: Name: Cees klein Tank, Drs.; Phone Number: +31 (024) 365 57 55; Email: cees.kleintank@radboudumc.nl
• Study Contact Backup: Name: Ignacio Malagon, Professor; Phone Number: +31 (024) 365 57 55; Email: ignacio.malagon@radboudumc.nl

Study Locations

• Netherlands
  • Gelderland
    • Nijmegen, Gelderland, Netherlands, 6525 GA
      • Recruiting
      • Radboud University Medical Centre
      • Contact: Cees klein Tank, Drs.; Phone Number: +31 (024) 365 57 55; Email: cees.kleintank@radboudumc.nl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

pediatric patients scheduled to undergo surgery with general anesthesia at the Radboud university medical centre in Nijmegen, the Netherlands

Description

Inclusion Criteria:

• Male or female
• ASA I, ASA II and ASA III
• Aged 1 to 12 years old
• Scheduled to undergo elective surgery with general anaesthesia

Exclusion Criteria:

• Patients with chronic pain
• Patients with chronic analgesia usage.
• Known allergy to the adhesives used in the sensors.
• No free available limb to attach the probes to.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Patients aged 1 to 12 years undergoing surgery with general anesthesia.

Device: Connecting all patients to the nociception level index(NOL) and the surgical pleth index (SPI); All patients will be connected to the NOL and SPI during surgery after induction of general anesthesia.; Device: All patient will receive a tetanic stimuli (60mA, 100hz) of 5 seconds before start of incision; All patient will receive a tetanic stimuli (60mA, 100hz) of 5 seconds before start of incision.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in surgical pleth index (∆SPI) during surgical stimuli and standardized tetanic stimuli	∆SPI = pre stimulus -30s-0s mean SPI value - post stimulus +5s to 30s-120s SPI value.	During surgery with general anesthesia.
Change in nociception level index (∆NOL) during surgical stimuli and standardized tetanic stimuli	∆NOL = pre stimulus -30s-0s mean NOL value - post stimulus +5s to 30s-120s NOL value.	During surgery with general anesthesia

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in surgical pleth index (∆SPI) following intraoperative opioid administration.	Response of the SPI to intraoperative administration of opioids. Evaluate SPI mean values -20s to 0s before opioid administration to mean value after opioid administration in accordance with the utilized opiod farmacokinetics(time of mean measurement in seconds depends on opioid used).	During surgery with general anesthesia]
Change in nociception level index (∆NOL) following intraoperative opioid administration.	Response of the NOL index to intraoperative administration of opioids. Evaluate NOL mean values -20s to 0s before opioid administration to mean value after opioid administration in accordance with the utilized opiod farmacokinetics(time of mean measurement in seconds depends on opioid used).	During surgery with general anesthesia
Time NOL index is >25 and SPI is >40 during surgery and before intra-operative opioid administration. Defined as time NOL index is >20-25 and SPI is >40 during surgery time.	Defined as time in seconds NOL index is >25 and SPI is >40 during surgery time.	During surgery with general anesthesia
Comparing mean (total surgery time) and last 5-min mean values before disconnection for intra-operative NOL and SPI to the post-operative pain scores.	For patients aged <4 Faces, legs, activity, cry and consolability (FLACC) will be used; For patients aged >4 a faces pain scale, numeric rating scale (NRS) or visual analogue scale (VAS) will be used.; Pain scores will be obtained at recovery admittance, after one hour and at recovery departure and when recovery personnel deem it is necessary based on their clinical view.	perioperative/periprocedural
Change in surgical pleth index (∆SPI) after administration of vasoactive medication.	Compare mean values -20 to 0 sec for administration of vasoactive medication to mean 5+-30 sec, 5+-60sec and 5+-120sec after administration vasoactive medication (noradrenaline, ephedrine and atropine).	During surgery with general anesthesia
Change in nociception level index (∆NOL) after administration of vasoactive medication.	Compare mean values -20 to 0 sec for administration of vasoactive medication to mean 5+-30 sec, 5+-60sec and 5+-120sec after administration vasoactive medication (noradrenaline, ephedrine and atropine).	During surgery with general anesthesia
Change in heartrate (∆HR) following a nociceptive event and opioid administration.	Change in heartrate following a nociceptive event. pre stimulus -30s-0s mean HR value - post stimulus +5s to 30s-120s HR value. Following opioid administration: Change in heartrate mean values -20s to 0s before opioid administration to mean value after opioid administration in accordance with the utilized opiod farmacokinetics(time of mean measurement in seconds depends on opioid used).	During surgery with general anesthesia
Change in mean arterial bloodpressure(∆MAP) following nociceptive event and opioid administration	Comparision of mean arterial bloodpressure measurement before nociceptive event/opioid administration to measurement after nociceptive event/opioid administration.	During surgery with general anesthesia
Change in respiratory rate (∆RR) following a nociceptive event and opioid administration.	Change in respiratory rate following a nociceptive event. pre stimulus -30s-0s mean HR value - post stimulus +5s to 30s-120s HR value. Following opioid administration: Change in respiratory rate mean values -20s to 0s before opioid administration to mean value after opioid administration in accordance with the utilized opiod farmacokinetics(time of mean measurement in seconds depends on opioid used).	During surgery with general anesthesia
Change in nociception level index (Δ NOL) after incision under loco-regional/neuraxial blockade.	Defined as Δ NOL following nociceptive stimuli in patients with an active loco-regional or neuraxial blockade. Compare mean values of SPI and NOL -30-0 before incision to mean 5+-30 sec, 5+-60sec and 5+-120sec after incision.	During surgery with general anesthesia.
Change in surgical pleth index (Δ SPI) after incision under locoregional/neuraxial blockade.	Defined as Δ SPI following nociceptive stimuli in patients with an active loco-regional or neuraxial blockade. Compare mean values of SPI and NOL -30-0 before incision to mean 5+-30 sec, 5+-60sec and 5+-120sec after incision.	Δ SPI
Response time of both monitors after nociceptive stimulation.	Defined as time in seconds of onset to change in SPI and NOL after nociceptive stimuli.	During surgery with general anesthesia

Collaborators and Investigators

• Sponsor: Radboud University Medical Center
• Investigators: Principal Investigator: Ignacio Malagon, Professor, Radboud University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): July 4, 2025
• Primary Completion (Estimated): July 31, 2026
• Study Completion (Estimated): July 31, 2026

Study Registration Dates

• First Submitted: July 2, 2025
• First Submitted That Met QC Criteria: July 24, 2025
• First Posted (Actual): July 25, 2025

Study Record Updates

• Last Update Posted (Actual): July 25, 2025
• Last Update Submitted That Met QC Criteria: July 24, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: NOL index; Pediatric population; Surgical pleth index; Nociception monitoring
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nociceptive Pain
• Other Study ID Numbers: 2025-18010

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No