Skip to main content
OpenTrials
Enrolling by Invitation

NCT Number: NCT07568405

The Effect of Remifentanil on the Objectively Measured Pressure Pain Threshold

It is a clinical study investigating the relationship between objectively measured pain threshold and the need for escalating doses of remifentanyl opioids. This study is expected to include approximately 40 participants.

The aim of the study is to objectively measure the analgesic effect of an increasing dose of opioids just before anesthesia.

Enrolling by Invitation

Interested in participating?

Request Info

Key information

Conditions

Pain Threshold Intravenous Anesthesia Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Postoperative Pain Signs and Symptoms Surgery

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

HUB Erasme

Brussels, Brussels Capital, 1070, Belgium

About this study

This is a prospective interventional study. Participants will undergo controlled pressure stimulation using an Algometer device to determine their pressure pain threshold (PPT).

Pressure pain threshold will be assessed at baseline (0 ng/mL) and during stepwise increasing target-controlled intravenous remifentanil concentrations of 1, 2, and 3 ng/mL. Measurements will be obtained at each concentration level after achieving steady-state conditions.

Investigators hypothesize that increasing plasma concentrations of remifentanil will be associated with a corresponding increase in pressure pain threshold.

In addition, postoperative analgesic consumption will be recorded following surgery. This will allow the investigators to explore a potential association between intraoperative pressure pain threshold modulation and postoperative pain outcomes or analgesic requirements.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Adult patients who are able to volunteer
  • ASA 1, 2and 3

Exclusion criteria

  • Refusal to participate;
  • Body mass index (BMI) > 30 kg/m²;
  • Allergy to any medication used for anesthesia;
  • Chronic pain or regular use of analgesics;
  • Severe ventricular dysfunction, pulmonary hypertension, or uncontrolled arrhythmia;
  • Non-elective surgery;
  • Participation in another study within the last 3 months;
  • Pregnancy or breastfeeding;
  • Severe renal or hepatic impairment

Treatment and study plan

Pressure pain theshold measured under remifentanil (ultiva®) infusion

Device

Upon arrival in the operating room, the patient will undergo standard monitoring, including non-invasive blood pressure, electrocardiography (ECG), pulse oximetry (SpO₂), bispectral index (BIS™), and train-of-four (TOF) monitoring.

An intravenous (IV) line will be placed, and crystalloid infusion will be initiated.

Mechanical pain threshold will then be assessed using a Medoc algometer. Measurements will be performed on the dorsum of the non-dominant hand. Four measurements will be obtained at different target plasma concentrations of remifentanil(Ultiva®): 0, 1, 2, and 3 ng/mL. Remifentanil will be administered using a target-controlled infusion (TCI) system based on the Minto pharmacokinetic model.

Following completion of these measurements, standardized intravenous anesthesia will be induced and maintained using propofol (propolipid®), remifentanil, and rocuronium (B.Braun®).

Total perioperative consumption of remifentanil and propofol will be recorded.

Postoperative PCA IV morphine (Sterop®) consumption and adverse events history

Drug

At the end of the surgical procedure, intravenous acetaminophen 1 g and a 4 mg morphine bolus will be administered.

Upon arrival in the post-anesthesia care unit (PACU), pain will be assessed using the visual analogue scale (VAS). During the first 24 postoperative hours, analgesia will be provided via a patient-controlled analgesia (PCA) pump delivering 2 mg intravenous HCL morphine (Sterop®) boluses on demand.

The PCA settings will follow a 2/10/20 regimen: 2 mg morphine per demand dose, a 10-minute lockout interval, and a maximum dose of 20 mg over 4 hours.

The use of acetaminophen as adjunct analgesia is permitted; however, corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), piritramide, and magnesium are prohibited.

Pain scores (VAS) will be reassessed at 12 and 24 hours postoperatively.

All adverse events (e.g., nausea, delirium) will be monitored and recorded during the 24-hour postoperative period.

Primary outcomes

  1. Measurement of the variation in the pressure pain threshold

    Time frame: Measurement of the mechanical pressure pain threshold will be initiated upon the participant's arrival in the operating room. The procedure is expected to last approximately 10-15 minutes and will be followed by induction of anesthesia.

    Change in mechanical pain threshold measured objectively using an algometer (AlgoMed®) at increasing plasma concentrations of remifentanil (0, 1, 2, and 3 ng/mL) during the preoperative period.

    The pain threshold is defined as the pressure (in kilopascals) at which the patient first reports pain during a standardized mechanical stimulus.

Secondary outcomes

  1. Correlation between preoperative pain threshold and total postoperative morphine consumption

    Time frame: From the day of surgery, prior to anesthesia induction, until 24 hours postoperatively.

    Correlation between preoperative pain threshold and total postoperative morphine consumption (particularly within the first 24 hours using patient-controlled analgesia).

    Postoperative pain scores assessed using standard pain scales in the post-anesthesia care unit.

    Intraoperative opioid (remifentanil) consumption in a standardized anesthesia setting.

    Post operative opioid (PCA, morphine) consumption recorded within the first 24H post surgery.

Sponsors and collaborators

Lead sponsor

Université Libre de Bruxelles

Other

Registry information

Official study title

L'Effet du rémifentanil Sur la sensibilité à la Douleur mesurée Objectivement

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
May 5, 2026
Registry last updated
May 5, 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.

Related clinical trials

Published trials that share one or more normalized conditions with this study.