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NCT Number: NCT07084935

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

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

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Key information

Conditions

Nociceptive Pain Anesthesia Neurologic Manifestations Nociception Monitoring Pain Pathological Conditions, Signs and Symptoms Pediatric Anesthesia Signs and Symptoms

Age range

1 year–12 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Radboud university medical centre

Nijmegen, Gelderland, 6525 GA, Netherlands

Location status: Recruiting

Location contact

Cees klein Tank, Drs.

CONTACT

[email protected]

+31 (024) 365 57 55

About this study

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.

Who can participate

Healthy volunteers accepted: No

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

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.

Treatment and study plan

Connecting all patients to the nociception level index(NOL) and the surgical pleth index (SPI)

Device

All patients will be connected to the NOL and SPI during surgery after induction of general anesthesia.

All patient will receive a tetanic stimuli (60mA, 100hz) of 5 seconds before start of incision

Device

All patient will receive a tetanic stimuli (60mA, 100hz) of 5 seconds before start of incision.

Primary outcomes

  1. Change in surgical pleth index (∆SPI) during surgical stimuli and standardized tetanic stimuli

    Time frame: During surgery with general anesthesia.

    ∆SPI = pre stimulus -30s-0s mean SPI value - post stimulus +5s to 30s-120s SPI value.

  2. Change in nociception level index (∆NOL) during surgical stimuli and standardized tetanic stimuli

    Time frame: During surgery with general anesthesia

    ∆NOL = pre stimulus -30s-0s mean NOL value - post stimulus +5s to 30s-120s NOL value.

Secondary outcomes

  1. Change in surgical pleth index (∆SPI) following intraoperative opioid administration.

    Time frame: During surgery with general anesthesia]

    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).

  2. Change in nociception level index (∆NOL) following intraoperative opioid administration.

    Time frame: During surgery with general anesthesia

    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).

  3. 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.

    Time frame: During surgery with general anesthesia

    Defined as time in seconds NOL index is >25 and SPI is >40 during surgery time.

  4. 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.

    Time frame: perioperative/periprocedural

    • 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.

  5. Change in surgical pleth index (∆SPI) after administration of vasoactive medication.

    Time frame: During surgery with general anesthesia

    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).

  6. Change in nociception level index (∆NOL) after administration of vasoactive medication.

    Time frame: During surgery with general anesthesia

    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).

  7. Change in heartrate (∆HR) following a nociceptive event and opioid administration.

    Time frame: During surgery with general anesthesia

    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).

  8. Change in mean arterial bloodpressure(∆MAP) following nociceptive event and opioid administration

    Time frame: During surgery with general anesthesia

    Comparision of mean arterial bloodpressure measurement before nociceptive event/opioid administration to measurement after nociceptive event/opioid administration.

  9. Change in respiratory rate (∆RR) following a nociceptive event and opioid administration.

    Time frame: During surgery with general anesthesia

    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).

  10. Change in nociception level index (Δ NOL) after incision under loco-regional/neuraxial blockade.

    Time frame: During surgery with general anesthesia.

    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.

  11. Change in surgical pleth index (Δ SPI) after incision under locoregional/neuraxial blockade.

    Time frame: Δ SPI

    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.

  12. Response time of both monitors after nociceptive stimulation.

    Time frame: During surgery with general anesthesia

    Defined as time in seconds of onset to change in SPI and NOL after nociceptive stimuli.

Study contacts

Contact information is provided by the study sponsor or research team.

Cees klein Tank, Drs.

CONTACT

[email protected]

+31 (024) 365 57 55

Ignacio Malagon, Professor

CONTACT

[email protected]

+31 (024) 365 57 55

Sponsors and collaborators

Lead sponsor

Radboud University Medical Center

Other

Registry information

Official study title

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

Acronym: NOLvsSPI

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jul 25, 2025
Registry last updated
Jul 25, 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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