26 Jan 2017

Screen all babies for heart disease, specialists urge

7:19 am on 26 January 2017

New Zealand must consider screening all newborn babies for congenital heart disease, medical specialists say.

Though congenital heart defects are rare, it is estimated that four babies a year die because of late diagnosis.

Researchers from the Liggins Institute and elsewhere are studying the feasibility of screening all newborns with pulse oximetry, already carried out in some hospitals.

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Pulse oximetry screening involves placing a probe, attached to a monitor, against a newborn's foot or hand to measure the amount of oxygen circulating in the blood. Photo: 123rf

The procedure involves a doctor or midwife placing probes against a child's foot or foot and hand, typically before they are discharged home, in the first day of life. The probe is attached to a monitor which measures the amount of oxygen circulating in the blood. Low levels could indicate critical congenital heart disease, which would mean a rapid trip to Auckland's Starship Children's Hospital for likely heart surgery.

Wellington Hospital neonatologist Helen Miller said two such cases several years ago convinced Capital and Coast District Health Board to begin screening all newborns.

"Prior to this happening we did have ... a couple of babies a year that would be transported up in a quite unwell situation to Starship Hospital for cardiac surgery who had presented quite late."

According to a recent New Zealand Medical Journal article, congenital heart disease is rare, at between four and 10 cases for every 1000 live-born infants.

But the director of the Liggins Institute at Auckland University and head of neonatology Frank Bloomfield estimates four babies die every year because of late diagnosis.

"In addition there will be other babies who fortunately do not die but will have suffered significant compromise because they were detected late.

"Late diagnosis often results in a baby becoming critically unwell, maybe collapsing at home and needing an emergency transfer to intensive care and then significant stabilisation before any attempt can be made to fix the cardiac problem that's there.

"That sort of clinical scenario can result in the baby suffering damage to organs including the brain."

Ultrasound tests during pregnancy detect up to half of cases, but Professor Bloomfield said it could be difficult to pick up at that stage.

Clinical examination of newborns can also detect problems, but pulse oximetry is more sensitive and more reliable, he said.

Professor Bloomfield is involved in a feasibility study to help officials decide whether national screening should be introduced. Questions include what the barriers to a successful programme might be and whether it would be cost effective.

With screening already under way in at least two centres, he worries about the development of a piecemeal approach.

"The concern about that approach is that it is not likely to be available to every single newborn baby and every family in New Zealand, and it would result in inequality.

"We believe that only a national screening programme can really mean that there is universal access to screening tests."

He said the pulse oximetry test was easy to do. "It doesn't take very long, it ... takes about five minutes to perform the screening test but of course every time you add another thing [that] takes five minutes, things all add up."

Lesley Dixon, of the College of Midwives, said the test was needed. "It's a simple, straightforward test that actually helps us identify babies that may have a congenital cardiac disease. And it's non-intrusive, it's not harmful to the babies essentially ... it's a useful test.

Dr Dixon points out that about 10 percent of women in this country give birth in a birthing unit, 3 percent give birth at home and many other women go home within a few hours of birth. The study would consider the right time for screening, within those limitations.

"Obviously there's always a midwife involved in care following the birth, so pragmatically obviously midwives are going to be the best people to undertake the screening."

Dr Miller said Wellington Hospital bought five extra oxygen saturation monitors, at about $900 each, when it decided several years ago to provide the screening to all those born at the hospital. Junior doctors and hospital midwives did the test, along with other well-child checks before babies were discharged home.

"But also in the community, I know that a number of community midwives have seen the value of this and have purchased saturation monitors for infants that perhaps aren't in the hospital system."

The Health Ministry's group manager for the National Screening Unit, Astrid Kornkeef, said advisers were supportive of screening but it was unclear how it should be implemented. Options included a nationally-led screening programme, a nationally-led quality improvement programme, or screening as part of improvements in routine care.

Ms Kornkeef said a pilot of pulse oximetry being run in Auckland "will help address a number of unanswered questions regarding the feasibility of implementing pulse oximetry as a national screening programme".