Pupillary Dilation Reflex (PDR) Evaluation During General Anesthesia

Study Overview
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Brief Summary
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In this study, the pupillary dilation reflex is measured as a nociceptive indicator during elective abdominal surgery under general anesthesia.

Detailed Description
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An infrared camera of the video pupillometer measures the pupillary dilation reflex (PDR) in response of a nociceptive stimulus. This autonomic reflex, parasympathetic mediated in sedated patients, can be generated by various pain stimuli (built in standardized protocol, surgical incision, …) The PDR is a robust reflex, even in patients under general anesthesia, and provides a potential evaluation of the autonomous circuit within the nociceptive evaluation based on pupil dilation upon A-delta and C fibers in both electrical or mechanic stimulation. This mono-centric project involving American Society of Anesthesiologists (ASA) classification I-II patients undergoing elective abdominal surgery under general anesthesia are recruited. Enrolled patients perioperative undergo PDR measurements at four different standardized times.

Official Title
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Pupillary Dilation Reflex (PDR) Evaluation During General Anesthesia: a Pilot Study

Conditions
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Pain

Intervention / Treatment
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* Device: Pupil dilation reflex measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled abdominal surgery ASA I-II Exclusion Criteria: History of eye deformity, invasive ophthalmologic surgery, impaired pupil reflex in advance Kown cranial nerve(s) deficit Infection of the eye Predicted difficult airway management (DAF Guidelines) Chronic opioid use (>3 months) Ongoing treatment with beta-blockers, dopamine antagonists, topical atropine

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pupil dilation reflex measurement<br>Four measurements of PDR during surgery at standardized times | Device: Pupil dilation reflex measurement<br>* Pupillometry (PDR) at four standardized times perioperatively after induction, before opioid administration after opioid administration, steady state surgical incision end of procedure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pupillary Reflex Dilation | Pupillary Reflex Dilation is measured four times intraoperatively as a possible indicator of success of analgesia | Perioperative phase | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient Movement | Patient movement during surgery as a common used indicator for pain | Perioperative phase | 
| Vital signs | Increased vital signs (heart rate, blood pressure) during surgery as a common used indicator for pain | Perioperative phase | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Heart Rate, Reflex, Pupillary, Monitoring, Intraoperative