Baby cooling cap turns conventional wisdom on its head

A plastic bathing cap filled with cool water may hold the key to preventing brain damage in new-born babies.

The results of a global study, published online in the Lancet today, demonstrate for the first time that the damage may not be irreversible.

The $100 head-cooling cap was developed in Auckland and is designed to cool the head to stop brain cells dying after a bruising birth.

The affliction devastates hundreds of families each year and is the commonest cause of multi-million pound lawsuits against Britain's National Health Service.

The polythene hat, worn for three days immediately after birth, saved one in six babies who suffered oxygen deprivation at birth from death or lifelong disability in a trial conducted in four countries, including New Zealand.

Doctors believe there is further potential to save more babies by refining the treatment. Studies are underway into total body cooling which could be simpler to control.

One or two babies in every 1000 born in New Zealand, or about 100 babies a year, are at risk of brain damage during birth. Brain damage caused by oxygen deprivation at birth affects 600-700 babies a year in the UK.

As well as being a catastrophe for the family, it is a major burden on society. The lifelong costs of care for a severely brain damaged baby can be as high as $13 million.

Often there is no warning of a problem throughout pregnancy until in the last critical moments disaster occurs. The umbilical cord may become trapped round the baby's head or the womb may rupture down a previous Caesarean scar. Once the baby is born the oxygen supply is restored - but by then it is too late. Any restriction of the blood flow to the brain was thought to cause damage within minutes.

Research a decade ago showed that when the brain is starved of oxygen damage does not occur immediately and there is a window of a few hours when the effects are treatable.

By cooling the brain, doctors believe they can interrupt the "chemical cascade" triggered by the lack of oxygen which leads to brain damage hours or days afterward.

John Wyatt, professor of neonatology at University College Hospital, London, said: "What this confirms is the brain damage is not irreversible at the moment of delivery which is what we have always believed. This is the clearest evidence that intervention at birth can improve the outcome."

For the trial, researchers in hospitals in Canada, the US, New Zealand and the UK selected 234 babies who were deprived of oxygen at birth and whom tests of electrical activity in the brain showed were at high risk of brain damage.

The cool cap was fitted to the baby's head within a few hours of birth lowering the temperature by 3-4 degrees. It was removed after 72 hours.

When the babies were examined 18 months later, the results showed the proportion who had suffered severe disability or death was reduced from 66 per cent in the group given conventional care to 55 per cent in those treated with the cooling cap.

This was improved to 48 per cent, achieving statistical significance, when the one fifth most severely affected babies who had least chance of recovery were excluded.

"It confirms what we would expect, that some babies are so severely affected that therapy can't help them. But what is encouraging is the larger group of whom one in six showed benefit," Professor Wyatt said.

"For the last 40 years it has been paediatric orthodoxy that babies should be kept warm. We are not changing the advice to parents - it is very important babies are kept warm - but this does turn conventional wisdom on its head."

Auckland University's Dr Peter Gluckman, who led the US$5-7 million ($8-11 million) trial, told the Herald last year that brain cells took time to die after an injury such as losing oxygen at birth.

"Cooling slows body processes down. One of the body processes it slows down is the process by which cells actually die," he said.

"We think the cooling slows the cell death down for long enough for protective mechanisms to repair the brain."

The Auckland team is not taking any commercial gain from the research and has sold its cooling cap design to a Seattle company, Olympic Medical, which paid for the trial and is expected to sell caps for about $100 apiece.

Dr Gluckman and the late Professor Tania Gunn, who died of cancer in 1999, tried cooling caps on newborn lambs and rats before testing them on the first babies.

Researchers at Auckland University's Liggins Institute and elsewhere will keep trying variations of the technique and work on the tricky problem of how to apply the cooling method to premature babies, who are much less robust.

But Dr Gluckman expects that hospitals will not wait for the perfect system now that the first big trial has shown that cooling can save lives.

Professor Andrew Whitelaw from the University of Bristol, another of the researchers, said: "We need to get further information on the timing and methods of cooling, as well as which babies are most suitable for treatment, before cooling becomes the standard care for oxygen deprived babies."

How it works

* Cold water is pumped round a skull cap to cool a baby's head from 37.8C to 34C.

* The rest of the baby's body is kept under a heat lamp to maintain the body temperature above 34.5C.

* Cooling slows down all body processes.

* In particular, cooling stops some brain cells that were damaged during birth from dying - helping the baby to recover.

- THE INDEPENDENT AND NZ HERALD