Background and Aim: Carbon monoxide (CO) poisoning is a significant public health issue that can cause delayed neuropsychological sequelae (DNS). DNS mechanisms involve oxidative stress, inflammation, and immune injury. Although hyperbaric oxygen therapy is widely used, its efficacy in preventing DNS remains inconclusive. Preclinical and retrospective studies suggest that Dexamethasone (anti-inflammatory and immunosuppressive) and N-acetylcysteine (antioxidant) may reduce DNS risk. This study hypothesizes that their combination can effectively prevent DNS.

Methods: This prospective pre-post intervention study will enroll CO poisoning patients into treatment (Dexamethasone + N-acetylcysteine) and control groups. The primary outcome is the incidence of DNS within six weeks post-treatment.

Objective: To determine whether combining Dexamethasone and N-acetylcysteine reduces the incidence of DNS following CO poisoning.

Inclusion Criteria:

• History and clinical symptoms consistent with CO poisoning (initial blood carboxyhemoglobin (COHb) levels >5%, or >10% for smokers).

Exclusion Criteria:

• Concurrent use of other potentially lethal toxins. Severe trauma or burns that could be fatal. No spontaneous heartbeat or blood pressure before arrival. Poisoning time exceeding 24 hours before hospital arrival. Minors (under 18 years of age). Pregnant women. Patients or their families refuse to sign the consent form. Contraindications for the use of Dexamethasone or N-acetylcysteine (such as severe allergies) or when the physician assesses the risks outweigh the benefits.