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.


Objectives: Hyperbaric oxygen therapy (HBO2) is recommended for symptomatic patients within 24-hour postcarbon monoxide poisoning. Previous studies have reported significantly better outcomes with treatment administered within 6 hours after carbon monoxide poisoning. Thus, we aimed to compare the neurocognitive outcomes according to HBO2 delay intervals.

Design: Retrospective analysis of data from our prospectively collected carbon monoxide poisoning registry.

Setting: A single academic medical center in Wonju, Republic of Korea.

Patients: We analyzed the data of 706 patients older than 16 years treated with HBO2 with propensity score matching. Based on carbon monoxide exposure-to-HBO2 delay intervals, we classified patients into the early (control, less than or equal to 6 hr) and late (case, 6-24 hr) groups. The late group was further divided into Case-1 (6-12 hr) and Case-2 (12-24 hr) groups. We also compared mild (nonintubated) and severe (intubated) groups.

Interventions: HBO2.

Measurements and main results: After propensity score matching, Global Deterioration Scale scores at 6 months postcarbon monoxide exposure showed significantly fewer poor outcome patients in the early than in the late group (p = 0.027). The early group had significantly fewer patients with poor outcomes than the Case-2 group (p = 0.035) at 1 month and than the Case-1 (p = 0.033) and Case-2 (p = 0.004) groups at 6 months. There were significantly more patients with poor prognoses at 6 months as treatment interval increased (p = 0.008). In the mild cohort, the early group had significantly fewer patients with poor 6-month outcomes than the late group (p = 0.033).

Conclusions: Patients who received HBO2 within 6 hours of carbon monoxide exposure had a better 6-month neurocognitive prognosis than those treated within 6-24 hours. An increase in the interval to treatment led to an increase in poor outcomes.

Trial registration: ClinicalTrials.gov NCT04656912.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Carbon Monoxide Poisoning / physiopathology
  • Carbon Monoxide Poisoning / therapy*
  • Cohort Studies
  • Female
  • Humans
  • Hyperbaric Oxygenation / methods
  • Hyperbaric Oxygenation / statistics & numerical data*
  • Male
  • Middle Aged
  • Propensity Score
  • Registries / statistics & numerical data
  • Republic of Korea
  • Retrospective Studies
  • Time-to-Treatment / statistics & numerical data*

Associated data

  • ClinicalTrials.gov/NCT04656912