An interventional study of Pressure pain theshold measured under remifentanil (ultiva®) infusion and Postoperative PCA IV morphine (Sterop®) consumption and adverse events history in Pain Threshold, Surgery and Postoperative Pain, sponsored by Université Libre de Bruxelles. Enrolling by invitation at 1 site in Belgium. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-05.
Sponsored by Université Libre de Bruxelles · Not applicable, Interventional, and Prevention
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.
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.
5,640 studies on the registry are indexed under Pain, Postoperative; 1,230 are open to participants now.
This study's planned enrollment of 40 is below the median of 75 across 4,821 interventional studies indexed under Pain, Postoperative.
Browse Pain, Postoperative studies →Université Libre de Bruxelles is the lead sponsor of 45 studies on the registry; 13 are open to participants now.
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Exclusion Criteria:
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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 · Drug: Postoperative PCA IV morphine (Sterop®) consumption and adverse events history
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.
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.
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.
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.
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.
Time frame: From the day of surgery, prior to anesthesia induction, until 24 hours postoperatively.
Plan to share: No
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Université Libre de Bruxelles