New baby screening test proposed to detect more heart defects

A pulse oximeter can help detect congenital heart defects in newborns by checking the level of oxygen in the blood. Photo / Supplied.

A group of baby experts wants a new screening programme established, to help reduce deaths and disease from congenital heart defects.

In today's New Zealand Medical Journal, they promote the idea of a national newborn screening programme based on testing with a device called a pulse-oximeter.

The screening test uses a light sensor to assess the level of oxygen in a baby's blood. It is quick, painless and safe. Detection of low oxygen levels prompts further examination by doctors.

A pulse oximeter. Photo / Supplied.

Babies are already screened, before or after birth, for a number of conditions, including hearing problems, metabolic disorders and Down syndrome.

Between four and 10 in every 1000 liveborn infants in New Zealand are diagnosed with a congenital heart defect each year, say the authors of the article.

Less than half of infants with critical congenital heart defects are diagnosed prior to birth, and 20 per cent are diagnosed after discharge from hospital.

"It is estimated that four babies die each year in New Zealand as a result of late-diagnosed CHD [congenital heart defects].

"The impact on permanent disability, especially neuro-developmental deficit, is likely to be greater, as late diagnosis of CHD is associated with a greater risk of hypoxaemia [oxygen shortage in the blood] and acidosis [excessive acidity], both of which are associated with neurological damage."

"Researchers are in agreement that the question no longer is whether pulse oximetry screening should be performed on newborn infants, but rather how best to deliver the test."

The test is already routinely done at five New Zealand hospitals, including the Auckland City, Wellington and Dunedin hospitals, and at the three community birthing units in Counties Manukau.

One of the authors of the article, neonatal specialist Dr Elza Cloete, is involved in a feasibility study to assess the impact and cost-effectiveness of a screening programme.

She said she and colleagues had talked with Health Ministry representatives about the options for expanding the screening nationwide, either as a national programme or as separate schemes run in each of the 20 district health boards.

Cloete said a national programme would be preferable as it would enable national auditing and other systems known to improve the quality of screening programmes.

The ministry's national screening advisory committee told her by letter that it supports the idea of pulse oximetry screening but isn't sure which option would be best:
• A programme run by the ministry's National Screening Unit;
• Screening run by DHBs, with a national "quality improvement programme"; or
• "Sector-led implementation with screening part of improvements in routine care ..."

The committee said it would review pulse-oximetry screening after the completion of the feasibility programme.