Acetylcysteine for delayed cognitive deterioration after acute carbon monoxide poisoning: A pilot randomized controlled trial

Background Delayed neurological complications are an important cause of disability after acute carbon monoxide (CO) poisoning, but an effective pharmacological preventive treatment has not been established. Acetylcysteine may reduce oxidative injury after CO exposure and could therefore lower the risk of later cognitive deterioration. Methods In this single-blinded randomized pilot trial, 63 adults with acute CO poisoning were assigned to receive either intravenous acetylcysteine at 300 mg/kg/day for 3 days or placebo, in addition to standard hyperbaric oxygen. The primary outcome was delayed cognitive deterioration, measured as change in Mini-Mental State Examination category between recovery from the acute episode and 3-month follow-up, signaling worsening cognitive status. Results In the intention-to-treat population, delayed cognitive deterioration occurred in 2 of 31 patients (6.5%) in the acetylcysteine group, and in 5 of 32 patients (15.6%) in the placebo group. The difference did not reach statistical significance (odds ratio: 0.37, 95% CI: 0.07–2.08, Fisher’s exact p=0.426). No serious adverse effects were observed. Conclusion Adjunctive intravenous acetylcysteine did not significantly reduce delayed cognitive deterioration in this pilot study. Any apparent inter-group difference should be interpreted cautiously given the limited sample size and the MMSE-based outcome definition. Further studies with larger samples and more standardized outcome assessment are needed.