Pupillometry in Identifying Risk of Postoperative Opioid-induced Respiratory Depression in Children Undergoing Tonsillectomy

Pupillometry in Identifying Postoperative Opioid-induced Respiratory Depression in Children Undergoing Tonsillectomy

This study will evaluate whether quantitative pupillometry measurements can be used to identify children at risk for postoperative opioid-induced respiratory depression (OIRD) following tonsillectomy. Opioid-induced respiratory depression is a serious and potentially life-threatening complication that can occur after surgery, and current monitoring approaches are limited in their ability to predict which patients are at highest risk.

In this prospective observational cohort study, approximately 300 pediatric patients undergoing tonsillectomy will undergo non-invasive pupillometry measurements at defined perioperative time points, including preoperative, intraoperative, and postoperative periods. Pupillometry measurements will be collected using a commercially available, FDA-regulated infrared pupillometer. These measurements will include pupil size, constriction and dilation velocities, and latency in response to light stimulation.

Pupillometry data will be collected for research purposes only and will not be used to guide clinical care or treatment decisions. Standard clinical care will not be altered as part of this study. Clinical outcomes, including the occurrence of postoperative opioid-induced respiratory depression, opioid use, sedation levels, pain scores, and other postoperative events, will be recorded from the medical record.

The goal of this study is to evaluate the relationship between pupillary response patterns and the occurrence of postoperative respiratory depression, and to support the development of predictive models that may improve early identification of patients at risk for opioid-related adverse events.

Study Overview

• Status: Recruiting
• Conditions: Respiratory Complications Due to Anesthesia; Postoperative Complications (Cardiopulmonary); Opioid-Induced Respiratory Depression
• Intervention / Treatment: Device: Infrared Pupillometry

Detailed Description

This is a prospective, observational cohort study designed to evaluate the relationship between perioperative pupillary responses and postoperative opioid-induced respiratory depression (OIRD) in pediatric patients undergoing tonsillectomy.

Approximately 300 participants aged 3 to less than 18 years will be enrolled across participating clinical sites. Pupillometry measurements will be obtained using a portable, automated infrared pupillometer at predefined perioperative time points, including preoperative baseline, intraoperative periods, and postoperative recovery. Measurements will include resting pupil diameter, pupillary light reflex parameters (including percent constriction, constriction velocity, dilation velocity, and latency), and pupillary unrest in ambient light.

Pupillometry measurements will be collected solely for research purposes and will not be used to guide clinical management. All patients will receive standard perioperative care as determined by the clinical team.

The primary outcome is the occurrence of postoperative opioid-induced respiratory depression, defined as persistent oxygen desaturation (SpO2 <90%) or respiratory rate <8 breaths per minute in the absence of airway obstruction in the post-anesthesia care unit. Secondary outcomes include opioid consumption, sedation scores, pain scores, and postoperative complications such as nausea and vomiting.

Data will be analyzed to assess the association between pupillary response parameters and the occurrence of respiratory depression, and to support development of predictive models for identifying patients at increased risk of opioid-related adverse events.

• Study Type: Observational
• Enrollment (Estimated): 300

Contacts and Locations

• Study Contact: Name: Alisha Maslanka, BS, CCRC; Phone Number: 412-491-2748; Email: alisha.maslanka@chp.edu
• Study Contact Backup: Name: Senthilkumar Sadhasivam, MD; Phone Number: 513-253-4684; Email: sadhasivams@upmc.edu

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94158
      • Not yet recruiting
      • UCSF Benioff Children's Hospital
      • Contact: Rachel Eshima McKay, MD; Phone Number: 415-310-7722; Email: Rachel.Eshima@ucsf.edu
      • Contact: Travis Rimando, BS; Phone Number: 415-260-8568; Email: Travis.Rimando@ucsf.edu
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15213
      • Recruiting
      • UPMC Children's Hospital of Pittsburgh
      • Contact: Alisha Maslanka, BS, CCRC; Phone Number: 412-491-2748; Email: alisha.maslanka@chp.edu
      • Contact: Himali Vyas, M.B.B.S; Phone Number: 734.203.9987; Email: vyash3@upmc.edu
      • Principal Investigator: Mihaela Visoiu, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of pediatric patients aged 3 to less than 18 years undergoing tonsillectomy with or without adenoidectomy at participating clinical sites. Participants will be enrolled from routine clinical care settings and will receive standard perioperative management. The study will include patients across a range of clinical characteristics representative of the typical pediatric tonsillectomy population.

Description

Inclusion Criteria:

• Age 3 to less than 18 years
• Scheduled to undergo tonsillectomy with or without adenoidectomy
• Planned postoperative recovery in a monitored clinical setting (e.g., post-anesthesia care unit)
• Ability to obtain informed consent from parent or legal guardian and assent from the participant when developmentally appropriate

Exclusion Criteria:

• Known neurologic or ophthalmologic conditions that may affect pupillary function
• Use of medications known to significantly alter pupillary response outside of standard perioperative care
• Inability to obtain adequate pupillometry measurements (e.g., due to eye injury or inability to safely perform measurement)
• Patients not receiving opioids as part of perioperative care
• Any condition that, in the opinion of the investigator, would interfere with study participation or data interpretation

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Pediatric Tonsillectomy Patients; Pediatric participants aged 3 to less than 18 years undergoing tonsillectomy. Participants will undergo non-invasive pupillometry measurements at predefined perioperative time points. Pupillometry data are collected for research purposes only and will not be used to guide clinical care. All participants will receive standard perioperative management as determined by the clinical team.

Device: Infrared Pupillometry; Non-invasive pupillometry measurements will be performed using a commercially available, FDA-regulated infrared pupillometer. Measurements will be collected at predefined perioperative time points for research purposes only and will not be used to guide clinical care.; Other Names: Quantitative Pupillometry

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of Postoperative Opioid-Induced Respiratory Depression	Postoperative opioid-induced respiratory depression is defined as the occurrence of either (1) oxygen saturation (SpO2) <90% for a sustained period, or (2) respiratory rate <8 breaths per minute, in the absence of airway obstruction, during the post-anesthesia care unit stay. Events will be identified from clinical monitoring data and medical record documentation.	From arrival in post-anesthesia care unit (PACU) through PACU discharge (up to 4 hours postoperatively)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Opioid Consumption	Total opioid dose administered during the intraoperative and immediate postoperative period, recorded from the medical record and normalized to body weight where appropriate.	From induction of anesthesia through transfer to the post-anesthesia care unit (PACU) (up to 2 hours) through PACU discharge (up to 4 hours postoperatively); data collection across these periods may extend up to 6 hours in total.
Sedation Level	Sedation level assessed using clinically documented sedation scales recorded during routine care in the post-anesthesia care unit (PACU), including scales such as the Richmond Agitation-Sedation Scale (RASS; range -5 to +4, where more negative values indicate deeper sedation) or equivalent institution-specific scales. Higher levels of sedation correspond to lower (more negative) scores.	During PACU stay (up to 4 hours postoperatively)
Pain Scores	Pain intensity scores measured using age-appropriate validated scales (e.g., Numeric Rating Scale or FLACC) as recorded during routine clinical care. The Numeric Rating Scale (0 to 10, where 0 indicates no pain and 10 indicates worst possible pain) and for the Face, Legs, Activity, Cry, Consolability (FLACC) scale (0 to 10, where higher scores indicate greater pain), as recorded during routine clinical care in the post-anesthesia care unit (PACU). Scale selection will be based on patient age and clinical appropriateness.	During PACU stay (up to 4 hours postoperatively)
Postoperative Nausea and Vomiting	Occurrence of nausea and/or vomiting documented in the medical record during the PACU stay.	During PACU stay (up to 4 hours postoperatively)

Collaborators and Investigators

• Sponsor: NeurOptics Inc
• Collaborators: National Institute on Drug Abuse (NIDA); University of California, San Francisco; University of Pittsburgh Medical Center
• Investigators: Study Director: Jeffrey W Oliver, PhD, NeurOptics Inc

Study record dates

Study Major Dates

• Study Start (Actual): May 4, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): April 30, 2027

Study Registration Dates

• First Submitted: April 28, 2026
• First Submitted That Met QC Criteria: May 4, 2026
• First Posted (Actual): May 7, 2026

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Analgesia; Pediatrics; Sedation; Anesthesia; Opioids; Postoperative Period; Hypoventilation; Pupillometry; Respiratory Depression; Pupillary Light Reflex; Oxygen Desaturation; Perioperative Monitoring; Opioid-Induced Respiratory Depression
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Pathologic Processes; Respiratory Tract Diseases; Neurobehavioral Manifestations; Respiration Disorders; Signs and Symptoms, Respiratory; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Respiratory Insufficiency; Agnosia; Postoperative Complications; Hypoventilation
• Other Study ID Numbers: NIH-OiRD; R44DA055407 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The study team has not yet determined whether individual participant data will be shared. Any future data sharing will be evaluated following study completion and will consider participant privacy, institutional policies, intellectual property considerations, and applicable NIH and regulatory requirements.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No