Hyperbaric Oxygen Therapy Initiation Time in Acute Carbon Monoxide Poisoning

NCT ID: NCT04656912

Last Updated: 2020-12-29

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

706 participants

Study Classification

OBSERVATIONAL

Study Start Date

2020-09-01

Study Completion Date

2020-10-30

Brief Summary

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Hyperbaric oxygen therapy (HBO2) is recommended for symptomatic patients within 24 h of carbon monoxide (CO) poisoning. However, previous major studies found significantly better outcomes with HBO2 in patients treated within 6 h. Currently, there is no consensus on a CO poisoning-to-HBO2 interval that would not be beneficial.

Therefore, the investigators aimed to evaluate the difference in therapeutic effect depending on the poisoning-to-HBO2 interval after CO exposure in patients with acute CO poisoning who received HBO2 within 24 h. The investigators compared the neurocognitive outcomes of patients according to HBO2 time intervals based on the outcomes of patients treated within 6 h (control group) with propensity score matching using the CO poisoning registry of our hospital.

Detailed Description

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In the United States, 50,000 patients with carbon monoxide (CO) poisoning are admitted to the hospital emergency departments annually, resulting in 1,500 deaths. CO poisoning can have serious neurologic sequelae. Immediate treatment, within 24 h after poisoning, is a reasonable recommendation for patients with CO poisoning. Most physicians do not treat with hyperbaric oxygen therapy (HBO2) 24 h after CO poisoning.

Weaver et al. conducted a double-blind randomized control trial (RCT) satisfying all Consolidated Standards for the Reporting of Trials guidelines, which showed that HBO2 significantly reduced the rate of cognitive sequelae than normobaric oxygen therapy (NBO2) 6 weeks and 12 months post-treatment in patients with acute symptomatic CO poisoning. Although the aforementioned study used a maximum poisoning-to-HBO2 interval of 24 h in the inclusion criteria, more than 60% of enrolled patients were treated with HBO2 in less than 6 h after CO poisoning and the mean poisoning-to-HBO2 time was 5.8 h. In addition, in a subgroup with poisoning-to-HBO2 interval \> 6 h, the mean interval was 8.6 h. Therefore, their study results were actually powered to determine the benefit of HBO2 within 6 h post-CO poisoning; hence, it is unknown whether HBO2 reduces the neurocognitive sequelae occurrence rate if performed beyond 6-12 h from CO poisoning.

Currently, there is no consensus on a CO poisoning-to-HBO2 interval that would not be beneficial. Therefore, the investigators aimed to evaluate the difference in therapeutic effect depending on the poisoning-to-HBO2 interval after CO exposure in patients with acute CO poisoning who received HBO2 within 24 h. The investigators compared the neurocognitive outcomes of patients according to HBO2 time intervals based on the outcomes of patients treated within 6 h (control group) with propensity score matching to make tight adjustments to significant differences in patient baseline characteristics using the CO poisoning registry of our hospital.

The investigators classified the patients included in the study into two groups: an early group (≤ 6 h, control group) and a late group (6-24 h, case group), based on the time from patient rescue from CO source to the start of the first HBO2 session. In addition, patients who received HBO2 at 6-24 h were divided into case 1 group (\> 6 h and ≤ 12 h) and case 2 group (≥ 12 h and ≤ 24 h), and outcomes were compared with those of patients who received HBO2 within 6 h from CO exposure. Moreover, the investigators classified poisoning severity based on the necessity for intubation; mildly and severely poisoned patients were defined as those not requiring and requiring intubation, respectively

Conditions

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Hyperbaric Oxygenation Carbon Monoxide Poisoning Time

Study Design

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Observational Model Type

COHORT

Study Time Perspective

RETROSPECTIVE

Study Groups

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Acute CO poisoning

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

Hyperbaric oxygen therapy

Intervention Type PROCEDURE

Patients with any symptoms and signs were treated with HBO2. During the first HBO2, initial compression was performed to 2.8 atmospheres absolute (ATA) for 45 min, followed by 2.0 ATA for 60 min. If an additional HBO2 was possible within 24 h, then 2.0 ATA was administered for 90 min. Moreover, if necessary, patients were treated with HBO2, even after 24 h, until all symptoms resolved.

Interventions

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Hyperbaric oxygen therapy

Patients with any symptoms and signs were treated with HBO2. During the first HBO2, initial compression was performed to 2.8 atmospheres absolute (ATA) for 45 min, followed by 2.0 ATA for 60 min. If an additional HBO2 was possible within 24 h, then 2.0 ATA was administered for 90 min. Moreover, if necessary, patients were treated with HBO2, even after 24 h, until all symptoms resolved.

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

* CO poisoned patients

Exclusion Criteria

1. Not treated with HBO2
2. \< 16 years old
3. Non-acute CO poisoning
4. Received HBO2 more than 24 h after poisoning
5. A history of previous stroke or neurocognitive diseases
6. Did not undergo follow-up until 6 months
7. Received specific treatment other than HBO2, such as therapeutic hypothermia
8. A history of previous CO exposure
9. A serious illness that can affect the patient's prognosis such as advanced cancer
10. A cardiac arrest before ED arrival
11. No recorded data on important variables, such as time from CO exposure to the start of first HBO2
Minimum Eligible Age

16 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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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

References

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Lee Y, Cha YS, Kim SH, Kim H. Effect of Hyperbaric Oxygen Therapy Initiation Time in Acute Carbon Monoxide Poisoning. Crit Care Med. 2021 Oct 1;49(10):e910-e919. doi: 10.1097/CCM.0000000000005112.

Reference Type DERIVED
PMID: 34074856 (View on PubMed)

Other Identifiers

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CO-HBO

Identifier Type: -

Identifier Source: org_study_id