Pupillary Unrest in Ambient Light, and Relationship to Opioid-Induced Respiratory Depression

University of California San Francisco (UCSF)

Status and phase: Completed; Phase 1

Conditions: Overdose of Opiate; Safety Issues; Respiratory Depression; Opioid; Intoxication, Perception Disturbance (Acute); Acute Pain

Treatments: Behavioral: Continuous conversational interaction; Drug: Remifentanil infusion

Study type: Interventional

Funder types: Other

Identifiers

NCT04301895

221163

Details and patient eligibility

About

Volunteers will receive a weight-based opioid (remifentanil) infusion for 10 minutes. In the first run, serial pupillary measurements (pupillary unrest, pupil diameter) will be taken at baseline, and at 2.5-minute intervals during the infusion and a 25-minute recovery period afterwards. After a washout period, the experiment will be repeated in each subject (second run). The two runs differ only by presence versus absence of verbal interaction.

Full description

Healthy volunteers aged 20-55 will receive a weight-based opioid (remifentanil) infusion for 10 minutes. Vital signs including SpO2, transcutaneous CO2, and respiratory rate will be continuously measured.

In the first run, serial pupillary measurements (pupillary unrest, pupil diameter) will be taken at baseline, and at 2.5-minute intervals during the infusion and a 25-minute recovery period afterwards. After a washout period, the experiment will be repeated in each subject (second run). The two runs differ only by presence of ongoing verbal interaction versus complete avoidance of verbal interaction.

Incidence of respiratory depression will be compared in the two protocols with or without verbal interaction. Correlation between pupil diameter and pupillary unrest with estimated opioid concentrations will be determined by regression. Difference between pupil measurement versus opioid concentration regressions will be compared by chi2.

Enrollment: 20 patients

Sex: All

Ages: 20 to 55 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy
• Able to provide informed consent

Exclusion criteria

• Active substance use disorder
• Prior opioid use disorder
• Opioid use within 30 days.

Trial design

Primary purpose: Diagnostic

Allocation: Non-Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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20 participants in 2 patient groups

Interactive

Other group

Description:

Subject will be asked to continually interactive with the investigators, answering a series of standard questions during the remifentanil infusion and recovery periods.

Treatment:

Drug: Remifentanil infusion

Behavioral: Continuous conversational interaction

Non-interactive

Other group

Description:

All verbal interaction will be avoided and extraneous sounds will be eliminated from the environment during the remifentanil infusion and recovery periods.

Treatment:

Drug: Remifentanil infusion