To date, there has been no consensus about the effect of hyperbaric oxygen therapy (HBOT) on the mortality of patients with carbon monoxide poisoning (COP). This retrospective nationwide population-based cohort study from Taiwan was conducted to clarify this issue.
Using the Nationwide Poisoning Database, we identified 25,737 COP patients diagnosed between 1999 and 2012, including 7,278 patients who received HBOT and 18,459 patients who did not. The mortality risks of the two cohorts were compared, including overall mortality, and stratified analyses by age, sex, underlying comorbidities, monthly income, suicide, drug poisoning, acute respiratory failure, and follow-up periods until 2013 were conducted. We also tried to identify independent mortality predictors and evaluated their effects.
Patients who received HBOT had a lower mortality rate compared to patients who did not (adjusted hazard ratio [AHR]: 0.74; 95% confidence interval [CI]: 0.67–0.81) after adjusting for age, sex, underlying comorbidities, monthly income, and concomitant conditions, especially in patients younger than 20 years (AHR: 0.45; 95% CI: 0.26–0.80) and those with acute respiratory failure (AHR: 0.43; 95% CI: 0.35–0.53). The lower mortality rate was noted for a period of 4 years after treatment of COP. Patients who received two or more sessions of HBOT had a lower mortality rate than those who received once only. Older age, male sex, low monthly income, diabetes, malignancy, stroke, alcoholism, mental disorders, suicide attempts, and acute respiratory failure were also independent mortality predictors.
HBOT is associated with a lower mortality rate in patients with COP, especially in those who were younger than 20 years and those with acute respiratory failure. The results provide important references for decision making in the treatment of COP.