Evaluating the Efficacy and Utility of the Automated Pupillometer in Pain Assessment and Opioid Administration Guidance During the Perioperative Period: A Randomized Controlled Trial

NCT07614607 | Active Not Recruiting

• 2 other identifiers: 202541314965BKP004-2025-ECRG
• Study Type: interventional
• Target: 68
• Locations: 1 country
• Sites: 1

Brief Summary

Effective intraoperative and postoperative pain management is critical for patient comfort and recovery, yet traditional methods for assessing pain under general anaesthesia are limited by their subjective nature and reliance on vital signs. Automated pupillometry, which gives the parameters of the pupillary light reflex (PLR) components, offers an objective and quantitative approach to evaluating nociception and pain. This study aims to evaluate the effectiveness of the automated pupillometry in enhancing early postoperative pain control and to assess its utility in guiding opioid administration during the perioperative period. A prospective, non-blinded randomized controlled trial will be conducted with 68 patients undergoing laparotomy for gastrointestinal surgery. Participants will be randomly assigned to either an interventional group, where analgesia is guided by automated pupillometry measurements, or a control group receiving standard pain management. Key outcomes include the time to first rescue analgesia, self-reported pain scores, opioid consumption. The automated pupillometry measurements will be taken at key surgical moments, including before induction, pre-incision, and during recovery. Pain scores and rescue analgesia use will be compared between groups using appropriate statistical tests, and Kaplan-Meier survival curves will analyze time to first rescue analgesia. Regression analyses will explore the relationship between pupillometry readings and postoperative pain. It is anticipated that the automated pupillometry guided group will experience longer intervals before requiring rescue analgesia and report lower pain scores, suggesting improved pain management and reduced opioid use. This study could validate automated pupillometry as an innovative tool for optimizing postoperative pain management, potentially improving patient outcomes by enabling more precise and effective analgesia in surgical settings.

Conditions

Postoperative Pain; Postoperative Pain Management

Keywords

pupillometry; automated pupillometry; post-operative pain; post-operative opiod consumption

Outcome Measures

Primary Outcomes (1)

• post operative opioid consumption

  the amount of post operative opioid consumption including rescue analgesia and patient controlled analgesia morphine usage would be recorded

  first 24 hours post operatively

Secondary Outcomes (1)

• The correlation between pupillary response metrics (% change, constriction velocity, dilatation velocity, NPi) and opioid dosage administered.

  automated pupillometry measurements will be done before induction, after induction, before skin incision, during skin incision, after skin incision, during skin closure, and at post anaesthesia recovery unit 10 min and 30 min.

Study Arms (2)

Intervention

ACTIVE COMPARATOR

Participants in the interventional group will receive an initial dose of 100 mcg IV fentanyl during induction. Remifentanil will be administered via effect-site target-controlled infusion (TCI), with a concentration effect (Ce) ranging from 2 to 8 ng/ml, titrated according to the anaesthetist's discretion. TCI remifentanil is increased by 0.5 ng/ml if pupillary diameter changes \> 20% of the baseline. Automated pupillometry will be measured before induction , after induction(baseline), before the surgical incision, after surgical incision and during skin closure. Additional analgesics could be administered as control arm. At the post anaesthesia recovery area, PLR will be measured at 10 min and at 30 min.Anaesthetists will give rescue morphine when the pupillary diameter changes \> 20% and repeat the measurement after 5 minutes

Drug: Opioid Analgesic; Device: automated pupillometry

Control

OTHER

Participants in the control group will receive anaesthetic and analgesic management as per the standard practice followed by the attending anaesthetist. Additional analgesics, including intravenous paracetamol, intravenous parecoxib, and abdominal plane blocks, will be provided if there are no contraindications. Automated pupillometry will be measured before induction , after induction(baseline), before the surgical incision, after surgical incision and during skin closure. At the post anaesthesia recovery area, PLR will be measured at 10 min and at 30 min.

Device: automated pupillometry

Interventions

Opioid Analgesic DRUG

Participants in the interventional group will receive an initial dose of 100 mcg IV fentanyl during induction. Remifentanil will be administered via effect-site target-controlled infusion (TCI), with a concentration effect (Ce) ranging from 2 to 8 ng/ml. TCI remifentanil is increased by 0.5 ng/ml if pupillary diameter changes \> 20% of the baseline after induction. The automated pupillometry measurement is repeated 5 mins after increment. Prior to skin closing, IV morphine 0.1 mg/kg during skin closing and automated pupillometry measurement is repeated to aim pupillary diameter is within 20% of baseline. Analgesics is titrated according to the anaesthetist's discretion and reason is documented if it is deviated from the protocol.

Intervention

automated pupillometry DEVICE

For both arms, automated pupillometry will be measured before induction , after induction(baseline), before the surgical incision, after surgical incision, during skin closure, at PACU 10 mins and at PACU 30 mins. For intervention arm only, the additional automated pupillometry measurement will be performed after administration of analgesia.

Control; Intervention

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• \. Patients aged 18 - 70 years old scheduled for elective/emergency laparotomy with clear awareness and good communication
• \. ASA (American Society of Anaesthesiologists) physical status I-III
• \. Expected to have moderate to severe pain in the early postoperative period

You may not qualify if:

• \. Patient with known pupillary abnormality (such as anisocoria, pharmacologic dilation, previous intraocular surgery)
• \. Pre-existing neurological disorder affecting pupillary reflexes
• \. Patients on chronic opioid therapy or with a history of substance abuse
• \. Non-consenting patients or those with cognitive impairments affecting informed consent

Sponsors & Collaborators

• University of Malaya: lead

Study Sites (1)

Universiti Malaya Medical Centre

Kuala Lumpur, Kuala Lumpur, 59100, Malaysia

Location

MeSH Terms

Conditions

Pain, Postoperative

Interventions

Analgesics, Opioid

Condition Hierarchy (Ancestors)

Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Pain; Neurologic Manifestations; Signs and Symptoms

Intervention Hierarchy (Ancestors)

Narcotics; Central Nervous System Depressants; Physiological Effects of Drugs; Pharmacologic Actions; Chemical Actions and Uses; Analgesics; Sensory System Agents; Peripheral Nervous System Agents; Central Nervous System Agents; Therapeutic Uses

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctor

Model Details: prospective, pragmatic, randomized controlled trial

Study Record Dates

• First Submitted: May 20, 2026
• First Posted: May 29, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): February 1, 2027
• Last Updated: May 29, 2026

Record last verified: 2026-05

Locations

MY (1)