The Effect of Remifentanil on the Objectively Measured Pressure Pain Threshold

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

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.

Study Overview

• Status: Enrolling by invitation
• Conditions: Postoperative Pain; Surgery; Intravenous Anesthesia; Pain Threshold
• Intervention / Treatment: Device: Pressure pain theshold measured under remifentanil (ultiva®) infusion; Drug: Postoperative PCA IV morphine (Sterop®) consumption and adverse events history

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Belgium
  • Brussels Capital
    • Brussels, Brussels Capital, Belgium, 1070
      • HUB Erasme

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Pressure pain theshold measured under remifentanil (Ultiva®) infusion and analgesic consumption; This is a single-arm study in which all patients will follow the same protocol. Study participation begins on the day of surgery, immediately prior to anesthesia induction, when the primary measurements are performed, and ends 24 hours postoperatively. During this period, analgesic consumption and adverse events will be monitored. Intervention 1: Pressure pain threshold under remifentanil infusion. Pressure pain threshold will be assessed using an algometer at baseline (0 ng/mL) and during stepwise increases in target-controlled intravenous remifentanil (Ultiva®) concentrations of 1, 2, and 3 ng/mL. Measurements will be obtained at each concentration level after achieving steady-state conditions. Intervention 2: Postoperative analgesic consumption and adverse events. Perioperative and postoperative analgesic drug consumption will be recorded. All adverse events will be systematically monitored and documented.

Device: Pressure pain theshold measured under remifentanil (ultiva®) infusion; 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.; Drug: Postoperative PCA IV morphine (Sterop®) consumption and adverse events history; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of the variation in the pressure pain threshold	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.	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.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between preoperative pain threshold and total postoperative morphine consumption	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.	From the day of surgery, prior to anesthesia induction, until 24 hours postoperatively.

Collaborators and Investigators

• Sponsor: Université Libre de Bruxelles

Study record dates

Study Major Dates

• Study Start (Actual): January 26, 2026
• Primary Completion (Estimated): June 15, 2026
• Study Completion (Estimated): June 15, 2026

Study Registration Dates

• First Submitted: March 17, 2026
• First Submitted That Met QC Criteria: April 30, 2026
• First Posted (Actual): May 5, 2026

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: pain threshold; remifentanil; posoperative pain
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Health Care Economics and Organizations; Economics
• Other Study ID Numbers: HUB2025549

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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