Can a common hospital gas help fight drug-resistant pneumonia? Premium

Researchers find high-dose inhaled nitric oxide may reduce drug-resistant pneumonia, but long-term efficacy and feasibility need further study.

Drug-resistant pneumonia remains a serious complication in intensive care units, where treatment options are limited. Pseudomonas aeruginosa in particular causes about one in five hospital pneumonias and often resists multiple drugs.

A research team at the Massachusetts General Hospital, Boston, affiliated with Harvard Medical School, has reported that a gas already used in neonatal care may have a role in addressing such infections. In a study published in Science Translational Medicine, researchers found that a high dose of inhaled nitric oxide reduced drug-resistant Pseudomonas in a large-animal ICU model.

The human body naturally produces nitric oxide; doctors also use it at low doses, typically 20-80 ppm, to widen blood vessels in the lungs of patients with acute respiratory failure.

Lorenzo Berra, associate professor of anaesthesia at Harvard Medical School and a senior author of the study, said the decision to test much higher concentrations was guided by earlier findings.

“At the low doses commonly used in clinical practice, nitric oxide mainly acts as a selective pulmonary vasodilator,” he said. In 2021, a mouse study by his colleagues “provided the biological rationale for selecting 300 ppm as the threshold likely required for antimicrobial activity.”

To test the approach in a setting mirroring a human ICU, the researchers studied 16 ventilated pigs with pneumonia caused by multidrug-resistant P. aeruginosa. They introduced the bacteria directly into the lungs and afforded the animals intensive care for three days.