CHARLOTTESVILLE, Va. - Medical researchers at the University of Virginia Health System have developed a method that may alert physicians to early stages of severe infection in newborn infants.
In a recent edition of the journal Pediatrics, two University of Virginia researchers - neonatologist Dr. M. Pamela Griffin and cardiologist Dr. J. Randall Moorman - describe a new system for detecting subtle abnormalities of the heartbeat that may forewarn doctors about infection before the baby looks sick.
"Infection is a major cause of illness and death in newborn babies, and especially in premature infants," Griffin said. "As many as 25 percent of very premature babies in intensive-care units develop serious bloodstream infections, making their death rate twice as high and hospitalizations much longer," she said.
Griffin and Moorman suspected that closer examination of heart- rate patterns or characteristics in premature or sick newborns might show changes that were too subtle to detect with heart rate monitors currently used in neonatal intensive care units.
Using a new kind of mathematical analysis, they found that infants did have abnormal heart rate characteristics hours before other signs of illness were evident.
"The characteristics we see in newborns who are developing infection are similar to the abnormalities we see in cases of fetal distress," Griffin said.
"Our point of view is that newborns are fetuses that have graduated into a new environment and are experiencing stress from different factors, like bacterial infections, but have a similar physiological response," she added.
The researchers worked with computer software engineers at Medical Automation Systems in Charlottesville to develop a continuous online monitoring procedure that requires no contact with the infant other than standard skin patches to monitor heart rate.
Three study groups
Griffin and Moorman studied three groups: babies showing signs of illness whose blood tested positive for infection; infants who had similar signs but had blood testing negative for infection; and a control group without signs of illness.
The infants were at high risk for infection because of low birth weight, prematurity and more than two weeks' hospitalization.
"We found that abnormal heart rate characteristics preceded visible symptoms by as much as 24 hours," Moorman said.
"That means something was happening early that doctors would not yet be aware of. By the time signs and symptoms show and prompt doctors to do blood tests, sepsis can have quickly developed to a severe level," he said.
Since the published work was completed, the researchers have studied 350 infants in intensive- care units at the University of Virginia and Wake Forest University School of Medicine in North Carolina. They found that the monitoring strategy developed at the University of Virginia was also effective at the second hospital.
Griffin and Moorman believe the earlier detection method will cut mortality and illness rates among babies in intensive-care units and save health-care dollars by shortening hospital stays.
The two medical researchers will soon begin a multicenter clinical study of their device to monitor heart rate characteristics to prepare to apply for approval by the federal Food and Drug Administration.