Premature babies lungs are vulnerable

Many pre-term babies develop breathing difficulties and suffer tissue damage because their under-developed lungs cannot cope.

But use of the gas, which relaxes the blood vessels, cut rates of death and disease by a quarter.

The research, by the University of Chicago, is published in the New England Journal of Medicine.

Inhaled nitric oxide gives neonatologists a simple and effective tool to help protect premature infants. Dr Michael Schreiber

The researchers also found that the gas can cut the risk of severe bleeding into the brain, and loss of brain tissue by almost half.

Respiratory distress syndrome is particularly common among premature babies born weighing less than 1,500 grams (3.3 pounds).

Not only is the condition life-threatening, but even among those who survive it can cause permanent tissue damage, slow growth and increase susceptibility to infection.

It is also associated with abnormal brain development.

Big difference

In the study, 64% of the 102 infants who received standard oxygen therapy died or developed chronic lung disease.

However, among the 105 who received standard therapy and inhaled nitric oxide the figure was cut to 49%.

Treatment was continued for one week. Now the researchers plan to test the impact of extending treatment to one month.

Study director Dr Michael Schreiber said: "Inhaled nitric oxide gives neonatologists a simple and effective tool to help protect premature infants.

"Our data demonstrate that starting nitric oxide soon after birth in at-risk babies has few downsides and makes a major difference in their long-term health.

"It did not rescue the sickest infants, but it was able to limit the extent of lung disease in many newborns at risk, preventing the lung damage that can cause lifelong illness."

Nitric oxide is produced naturally by the body, and is used to transmit chemical signals.

It can dilate constricted blood vessels by relaxing the muscles that line them, and has been used to treat infants with a life-threatening condition called pulmonary hypertension.

Fear of complications

However, it can also interfere with the blood's clotting mechanism, and the Chicago team were concerned that giving it to premature babies might increase the risk of bleeding and tissue damage in the brain.

These complications are the primary cause of serious long-term brain damage in premature babies and are associated with the subsequent development of cerebral palsy and mental retardation.

The researchers found that nitric oxide did not cause either problem. Instead, it seemed to prevent the most severe brain injuries.

Although nitric oxide did not reduce the risk of all neurologic complications, only 12% of the infants who received it suffered a severe brain haemorrhage or tissue damage, compared to 24% of those who did not.

Infants who received nitric oxide also tended to spend less time on the ventilator and required less time in the hospital.

However, Dr Richard Martin, of Case Western Reserve University in Cleveland, warned that treatments for premature babies sometimes turned out to cause more harm than good.

He said: "The jury is still out. Extreme caution is justified."