September 8, 2011

Special heart rate monitor reducing infant mortality

Featured Image

Judy Aschner, M.D., in the NICU with the HeRO heart rate monitoring system that can detect signs of infection before symptoms appear. (photo by Joe Howell)

Special heart rate monitor reducing infant mortality

There’s a HeRO in the Neonatal Intensive Care Unit at Monroe Carell Jr. Children's Hospital at Vanderbilt, and it’s saving lives.

A recent study published in The Journal of Pediatrics shows that a specialized heart rate monitoring system, appropriately named HeRO, can reduce infant mortality by more than 20 percent. One infant’s life was saved for every 48 monitored, results showed.

The monitoring system for premature infants checks the heart’s beat-to-beat variability, and can use that information to detect early signs of an infection long before any symptoms appear. The Children’s Hospital NICU is the only nursery in Nashville to have the HeRO system.

Researchers had set out to examine if heart rate characteristic monitoring improves outcomes in neonates, such as reducing hospital stays. The six-year, randomized trial involved 3,003 low-birth weight infants (less than 1,500 grams) at nine sites around the country, including Children’s Hospital. About 230 infants at Vanderbilt were enrolled in the trial.

“We never dreamed it would reduce mortality,” said Judy Aschner, M.D., chief of Neonatology and Julia Carell Stadler Professor of Pediatrics. “We didn’t imagine that something as non-invasive, simple and safe as creating a mathematical algorithm out of a heart rate would allow us to save lives.”

Children’s Hospital has had the system for four years. Once the clinical trial finished, every infant in the unit was placed on the monitoring system, which is connected to the bedside heart monitor in each room.

The system analyzes the heart rate variability continuously and generates a digital score from 0 up to 7. If the heart rate becomes too constant (looses variability) or there are decelerations — a sign the infant may have an infection — the score rises. Scores above a 2 start to draw attention.

Doctors are able to get out ahead of any illness the infant may be developing, using antibiotics and drawing blood cultures to confirm an infection.

“The hero score seems to be an early harbinger of an infant who is starting to get an infection,” said Aschner. “It will start to rise in a baby who is getting ill long before the baby has any symptoms that we can tell. It’s an extra piece of information that, it turns out, when used appropriately can save lives.”

Among the trial participants in the nine centers, there were 152 deaths in the group that received standard NICU care. In the group that received standard care plus HeRO monitoring, there were 122 deaths, representing an absolute risk reduction of 2.1 percent. For the smallest infants (less than 1000 grams or 2.2 pound) who are at greatest risk of infection, one life was saved for every 23 infants monitored.

This multi-center study was co-sponsored by the National Institutes of Health (NIH) and Medical Predictive Science Corporation (MPSC).