An increase in the use of “gentler” less invasive breathing support for premature babies over the last quarter of a century hasn’t translated to better respiratory function in the long-term, Victorian research concludes.

The study by the Victorian Infant Collaborative Study Group followed all extremely preterm infants (22 to 27 weeks gestation) born in the state during 1991-92, 1997 and 2005.

They discovered that the 2005 group received more assistance with breathing for a longer period than the earlier groups, but their lung function at age eight was worse.

Rates of oxygen dependence at 36 weeks were also higher in the 2005 birth cohort than in the other infants, the study found.

Professor Lex Doyle, from neonatal services at the Royal Women’s Hospital in Melbourne, told the limbic prolonged oximetry in recent years might have contributed to overuse of nasal CPAP.

“These oximeters are very useful and we can leave them on for a long time – even when they are breathing normally. We might be leaving them on too long, seeing more than we need to see and treating more than we need to treat.”

The study also found expiratory flows at eight years of age were lower than expected and worse in the 2005 birth cohort than the earlier 1997 cohort.

“Because we were using more of a gentler way of assisting breathing, we had hoped that the lungs would be a little better,” Professor Doyle said.

“I should emphasise that most children are fine – for example, their rates of asthma were similar across the group at about 25%.”

Professor Doyle highlighted the ongoing need for research on newer ways of assisting babies to breathe such as high-flow nasal prong therapy. Importantly, there should be sufficient funding to measure long-term outcomes, he said.

Professor Doyle added that keeping babies in the uterus for as long as possible was one way to minimise the risks.

“Certainly, in the US 10-15 years ago, there was a lot of over-diagnosis and over-intervention to deliver babies just a bit early. Even babies born three to five weeks too early are at a disadvantage.”

He said respiratory physicians should be aware that patients with a history of prematurity would have more airway obstruction and present with more respiratory problems.

An accompanying editorial  said the Australian study provided evidence that prolonged, noninvasive support and oxygen therapy was associated with unanticipated adverse outcomes.

It said neonatologists should “critically appraise the indications for noninvasive ventilation in every preterm infant”.

The findings also suggested that we should not rush to embrace newer, noninvasive approaches to respiratory support in the belief that less is always more.