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Completed

NCT Number: NCT06663761

Correlation of Pain Intensity Measurements in Healthy Volunteers Exposed to Unpleasant Stimuli

Pain is an unpleasant sensory and emotional phenomenon that can be caused by tissue damage or potentially harmful stimuli. Pain is by definition a subjective phenomenon, and everyone experiences it differently, which creates problems in its assessment and treatment. There are many ways to measure pain, both through patient self-report (scales) and objective physiological indicators. However, there is no single, universal tool for measuring pain intensity that is simultaneously reliable, valid, and easy to use. Moreover, there are reports showing that not only the intensity of the unpleasant experience but also the nature of the stimulus can cause different levels of changes in the used indicators and scales. In this project, we will compare two devices used for pain monitoring based on physiological parameters: PainMonitor (Med-Storm, Oslo, Norway) and ANI Monitor (MetroDoloris, Loos, France). PainMonitor is a device that records skin conductance (SC) as an indicator of pain intensity. SC reflects the level of autonomic nervous system arousal. The device automatically analyzes these parameters and provides a numerical indicator of pain intensity/anesthesia level. The ANI Monitor is a device based on the analysis of parasympathetic nervous system activity through heart rate variability analysis. Based on this, the device also assesses the degree of pain intensity and presents it in numerical form. The aim of the project is to investigate the correlation between PainMonitor and ANI as tools for measuring pain intensity in situations where healthy volunteers are exposed to various unpleasant stimuli.

The study will involve approximately 100 healthy adult participants who will be exposed to three types of standardized stimuli: thermal (hot and cold), mechanical (pressure from a blood pressure cuff, pressure on a skin fold), chemical (spicy taste), and visual. Simultaneously, they will be monitored by PainMonitor, ANI, ECG, and peripheral perfusion index (using pulse oximetry). This data will then be compared and subjected to statistical analysis to determine if there is a relationship between the nature of the stimuli used and the objective and subjective indicators of pain intensity.

Stimuli (the order of stimuli 1-4 will be electronically randomized), with a break time between stimuli of 5-10 minutes:

1. NON-INVASIVE BLOOD PRESSURE MEASUREMENT: Non-invasive blood pressure measurement (NIBP) (single automatic blood pressure measurement using a Phillips IntelliVue Monitor). 2. HEAT: A metal cube with a temperature of 45 degrees Celsius will be used for heat stimulation. The cube will be applied for 60 seconds to the inner side of the forearm of the participant's dominant hand. The appropriate temperature of the cube will be maintained by keeping it in a water bath. 3. ALGOMETER: For mechanical stimulation, the researcher will apply pressure to the skin fold between the second and third fingers of the dominant hand using an algometer. The pressure will gradually increase from 0 to 250-300 kilo Pascal (kPa) and be maintained for 60 seconds. 4. VISUAL STIMULUS: For visual stimulation, a video will be shown on a display in front of the participant, depicting a model having a short intravenous cannula inserted. Participants will be asked to imagine that the hand on the screen is their own. 5. COLD: "Cold pressor test" - The participant's forearm will be immersed in water at a temperature of 2 degrees Celsius for 60 seconds or until discomfort causes the participant to withdraw their hand. 6. SPICY TASTE: 0.5 ml of spicy sauce with a specified amount of Scoville units will be applied to the participant's tongue using a syringe.

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Key information

Conditions

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

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Medical University of Gdansk - Departament of Anesthesiology and Intensive Care

Gdansk, Pomeranian Voivodeship, 80-210, Poland

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • American Society of Anesthesiology (ASA) general condition assessment 1 or 2
  • age 18 - 40 yrs

Exclusion criteria

  • any arrhythmia,
  • taking medications from the groups of beta-blockers, gabapentinoids, benzodiazepines, painkillers within the last 12 hours,
  • chronic pain conditions,
  • pregnancy,
  • trypanophobia (fear of needles)

Treatment and study plan

Stimuli

Behavioral

Stimuli (the order of stimuli 1-4 will be electronically randomized), with a break time between stimuli of 5-10 minutes:

  • Non-invasive blood pressure measurement
  • Heat
  • Mechanical stimulation
  • Visual stimulation
  • Cold pressor test
  • Spicy taste

Primary outcomes

  1. Pain Monitor Measurements.

    Time frame: Continuously throughout whole study - approximately 1.5 hours

    Skin conductance will be recorded using PainMonitor (Med-Storm, Oslo, Norway) - on the non-dominant hand.

  2. Heart rate and its variability (HRV) - high frequencies

    Time frame: Continuously throughout whole study - approximately 1.5 hours

    Heart rate and its variability (HRV) will be recorded using a Holter ECG monitor - electrodes on the chest. Frequency domain method will be used. The number of NN (beat to beat) intervals that match high frequency band (0.15 to 0.4 Hz) will be recorded.

  3. Heart rate and its variability (HRV) - low frequencies

    Time frame: Continuously throughout whole study - approximately 1.5 hours

    Heart rate and its variability (HRV) will be recorded using a Holter ECG monitor - electrodes on the chest. Frequency domain method will be used. The number of NN (beat to beat) intervals that match low frequency band (0.04 to 0.15 Hz) will be recorded.

  4. The analgesia-nociception index (ANI)

    Time frame: Continuously throughout whole study - approximately 1.5 hours

    The analgesia-nociception index (ANI) will be recorded using a dedicated device (MetroDoloris, Loos, France).

  5. Perfusion index (PI)

    Time frame: Continuously throughout whole study - approximately 1.5 hours

    Perfusion index (PI) will be recorded using the pulse oximeter of the Phillips IntelliVue monitor - index finger of the non-dominant hand.

  6. Subjective discomfort/pain - NRS

    Time frame: After each stimuli - approximately 1.5 hours

    Subjective discomfort/pain will be monitored using the Numerical Rating Scale (NRS, 0-10).

  7. Subjective discomfort/pain - McGill Pain Questionnaire

    Time frame: After each stimuli - approximately 1.5 hours

    Subjective discomfort/pain will be monitored using the McGill Pain Questionnaire (SF-MPQ).

Sponsors and collaborators

Lead sponsor

Medical University of Gdansk

Other

Registry information

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Oct 29, 2024
Registry last updated
Jul 10, 2026

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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