Inhaled nitric oxide in advanced paraquat intoxication

Area of Science:

• Toxicology
• Pulmonology
• Critical Care Medicine

Background:

• Severe paraquat poisoning presents significant challenges with no established effective treatments for critical complications like adult respiratory distress syndrome, pulmonary hypertension, and lung fibrosis.
• Current supportive care for advanced paraquat intoxication often involves mechanical ventilation and high oxygen concentrations, with limited success in improving gas exchange.

Observation:

• A case study involving a 52-year-old female with severe paraquat intoxication, presenting with profound hypoxemia (PaO2 ≤ 50 mm Hg) despite maximal ventilatory support.
• Administration of inhaled nitric oxide (25 ppm) led to a significant increase in partial arterial oxygen pressure (PaO2) and a decrease in mean pulmonary artery pressure and right-to-left shunt.

Findings:

• Inhaled nitric oxide therapy demonstrated a potentially beneficial effect on gas exchange and hemodynamics in a patient with advanced paraquat poisoning.
• Discontinuation of nitric oxide resulted in rapid deterioration of respiratory parameters, highlighting its temporary efficacy.
• Despite temporary stabilization, the patient developed pleural effusions and ultimately died, with post-mortem findings revealing extensive myonecrosis, suggesting paraquat-induced myopathy.

Implications:

• Inhaled nitric oxide therapy warrants further investigation as a potential adjunctive treatment for severe paraquat intoxication, particularly for managing pulmonary complications.
• The findings underscore the complex and potentially prolonged toxicity of paraquat, with late-onset myopathy or neuromyopathy being a possible manifestation.
• This case highlights the critical need for novel therapeutic strategies to improve outcomes in paraquat poisoning.