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Quantitative Assessment of Pupillary Light Reflex in Acute Carbon Monoxide Poisoning

NCT ID: NCT05110820

Last Updated: 2021-11-08

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

104 participants

Study Classification

OBSERVATIONAL

Study Start Date

2019-08-01

Study Completion Date

2021-01-31

Brief Summary

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Neurological complications after acute carbon monoxide (CO) poisoning can range from transient headache or dizziness to cognitive dysfunction, seizure, permanent anoxic brain damages or death. A recent study reported that a lack of standard pupillary light reflex (sPLR), assessed using a pen light, was a predictor of 30-day neurological sequelae in patients with CO poisoning. Given that the basic sPLR has a poor inter-rater reliability, more objective and quantitative methods are required in the assessment of PLR.

An automated pupillometer has been used in the intensive care unit to quantitatively assess the PLR. Therefore, we hypothesized that quantitative assessment of PLR might be associated with neurocognitive sequelae after acute CO poisoning. The purpose of this study was to assess the value of quantitative pupillary reactivity (NPi and qPLR) in comparison to that of sPLR in predicting neurocognitive outcome at 1 month after acute CO poisoning.

Detailed Description

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Neurological complications after acute carbon monoxide (CO) poisoning can range from transient headache or dizziness to cognitive dysfunction, seizure, permanent anoxic brain damages or death. Although hyperbaric oxygen therapy (HBO2) has been tried to minimize the neurological complications, a significant percentage of patients still suffer from neurocognitive sequelae after acute CO poisoning. A recent study reported that a lack of standard pupillary light reflex (sPLR), assessed using a pen light, was a predictor of 30-day neurological sequelae in patients with CO poisoning. Given that the basic sPLR has a poor inter-rater reliability, more objective and quantitative methods are required in the assessment of PLR.

An automated pupillometer has been used in the intensive care unit to quantitatively assess the PLR. Quantitative PLR (qPLR), which is expressed as the percentage pupillary constriction in response to a calibrated light stimulus, was better in predicting neurological outcome after cardiac arrest (CA) compared to standard light reflex. In addition, the Neurological Pupil index (NPi) has been validated as a tool for assessing prognosis after CA because it is not influenced by medications (especially opioids and neuromuscular blocking agents) or small pupil size.

Therefore, the investigators hypothesized that quantitative assessment of PLR might be associated with neurocognitive sequelae after acute CO poisoning. The purpose of this study was to assess the value of quantitative pupillary reactivity (NPi and qPLR) in comparison to that of sPLR in predicting neurocognitive outcome at 1 month after acute CO poisoning.

Conditions

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Carbon Monoxide Poisoning

Study Design

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Observational Model Type

COHORT

Study Time Perspective

PROSPECTIVE

Study Groups

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Acute CO poisoning

A diagnosis of CO poisoning was made according to medical history and carboxyhaemoglobin \>5% (\>10% in smokers).

Automated quantitative pupillometer

Intervention Type DIAGNOSTIC_TEST

Quantitative measurement of pupillary variables was performed at the time of arrival at the ED (0 h), and at the 6-, 12-, and 24-h time points on hospital day (HD) 1. The worst value among those recorded within 24 h and during the total measurement period was selected as the 24-h and total lowest values. If a patient was discharged before HD 3, measurements were taken only until discharge. The initial value was measured within 1 h after arrival at the ED because of the requisite time for obtaining informed consent before enrollment. At each time point, the lowest values for the NPi and qPLR of each eye were retained for analysis. The sPLR (standard PLR) was serially measured in the ED and after admission by emergency physicians using a manual penlight. We classified the reactivity of the sPLR as reactive, sluggish, or non-reactive. Non-reactive sPLR was defined when pupillary reactivity was not identified bilaterally.

Interventions

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Automated quantitative pupillometer

Quantitative measurement of pupillary variables was performed at the time of arrival at the ED (0 h), and at the 6-, 12-, and 24-h time points on hospital day (HD) 1. The worst value among those recorded within 24 h and during the total measurement period was selected as the 24-h and total lowest values. If a patient was discharged before HD 3, measurements were taken only until discharge. The initial value was measured within 1 h after arrival at the ED because of the requisite time for obtaining informed consent before enrollment. At each time point, the lowest values for the NPi and qPLR of each eye were retained for analysis. The sPLR (standard PLR) was serially measured in the ED and after admission by emergency physicians using a manual penlight. We classified the reactivity of the sPLR as reactive, sluggish, or non-reactive. Non-reactive sPLR was defined when pupillary reactivity was not identified bilaterally.

Intervention Type DIAGNOSTIC_TEST

Eligibility Criteria

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Inclusion Criteria

* Acute CO poisoning

Exclusion Criteria

* Age \<19 years
* Patients with a history of ophthalmic surgery which might have affected the PLR
* Patients with baseline cognitive deficit
* Refusal to enroll in this study
* Discharge from the ED or transfer to another hospital within 24 hours
* Expired in the ED
* Co-ingestion of drugs, such as hypnotics, that may affect the PLR
* No follow-up for the neurocognitive outcome
Minimum Eligible Age

19 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Seoul National University Bundang Hospital

OTHER

Sponsor Role collaborator

Wonju Severance Christian Hospital

OTHER

Sponsor Role lead

Responsible Party

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Yong Sung Cha

Assistant Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

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Wonju Severance Christian Hospital

Wŏnju, Gangwon-do, South Korea

Site Status

Countries

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South Korea

Other Identifiers

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CO-pupillometer

Identifier Type: -

Identifier Source: org_study_id