Another study found that giving nitric oxide to premature babies with breathing trouble can reduce their risk of death, lingering lung problems and brain damage - a finding that could help make the gas standard treatment in a few years.

In a study of 207 babies, doctors at the University of Chicago found major benefits from giving a low dose of nitric oxide gas to premature newborns with respiratory distress, or inability to breathe in enough air.

The one-week treatment cut their risk of death or lung problems to 49 per cent, compared with 64 per cent in preemies getting just oxygen from a breathing machine. The preemies breathing nitric oxide were 47 per cent less likely to develop severe bleeding in the brain and damage to brain tissue.

Those babies also spent less time on a breathing machine and went home sooner.

'This is not a baby step. This is a major step in the advancement of care for premature infants,' said Dr. Jessie Roberts, associate professor at Harvard Medical School and a neonatologist at Massachusetts General Hospital.

Nitric oxide - not to be confused with the 'laughing gas' nitrous oxide - is produced by many cells in the body. Among other things, it reduces inflammation and dilates blood vessels in the lungs, getting more oxygen into circulation.