High-Dose Inhaled Nitric Oxide for Drug-Resistant Pneumonia

Why in News?

Recently, researchers reported that high-dose inhaled nitric oxide reduced drug-resistant bacteria in a large-animal ICU model and was found safe in early human testing.

Pneumonia

• It is an infection of the lungs that causes inflammation of air sacs (alveoli) and accumulation of fluid or pus in the lungs.
  • Type – It can range from mild to severe and may be life-threatening, and can affect one or both lungs.
• Causes – Bacterial causes – Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila, Mycoplasma pneumoniae.
• Viral causes – Influenza, COVID-19, respiratory syncytial virus, human metapneumovirus.
• Fungal cause – Pneumocystis jirovecii (PCP), especially in immunocompromised (weakened immune system) individuals.
• Symptoms – Fever, chills, cough with mucus, breathlessness, chest pain, fatigue, loss of appetite, bluish lips/nails, nausea/vomiting in children, and confusion in the elderly.
• Risk factors – Chronic diseases, weak immunity, smoking, pollutant exposure, indoor biomass fuel use, crowded living conditions, parental smoking.
• Transmission – Community-acquired, hospital/ventilator-associated, or aspiration of food/liquids into lungs.
• Diagnosis – Clinical exam, imaging, blood tests, sputum test, pulse oximetry.
• Treatment – Antibiotics/other drugs, pain and fever medicines, oxygen or IV fluids in severe cases, hospitalisation if needed, rest and hydration.

Nitric Oxide Therapy for Drug-Resistant Pneumonia

• Caused by – Drug-resistant Pseudomonas aeruginosa.
  • Causes about one in five hospital pneumonias and resists multiple drugs.
• Nitric oxide – Naturally produced by the human body.
• Medical use – Low doses are used to widen blood vessels in acute respiratory failure.
• Key Findings – High-dose inhaled nitric oxide (300 ppm) reduced lung bacterial counts by 99% in ventilated pigs with multidrug-resistant pneumonia.
• Improved oxygenation and lung function and reduced need for blood pressure drugs.
• Human Testing – Phase-1 human study showed no serious adverse effects in healthy volunteers.
• Feasibility tested in critically ill ICU patients without immediate serious complications.
• Risk and Limitations – Potential toxic effects – Elevated methemoglobin and direct lung injury.
• Bacterial rebound is possible after stopping treatment.
• Long-term benefits are not proven and require clinical efficacy trials.
• Practical barriers – Requires specialised equipment, trained staff, and continuous monitoring for high-dose delivery.

Reference

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