Stanford University researchers have developed a method for predicting health problems in premature babies that they say is much more reliable than the standard Apgar score used to evaluate newborns’ health.
The method, which the researchers have named the PhysiScore, rates infants’ health based on vital signs taken at birth and during the first three hours of life. In a study of 138 infants at Lucile Packard Children’s Hospital, the score was able to predict a baby’s chances of developing serious illnesses with an accuracy of 91 to 98 percent.
The Apgar score has been favored for more than 50 years because it’s simple and fast — in the seconds after birth, doctors consider five health factors, such as how well an infant cries and how much he or she squirms, and they assign a score.
But the Apgar test is more subjective. The PhysiScore relies on hard data, including a newborn’s weight, heart rate and respiratory rate. At the same time, the PhysiScore is fairly easy to determine because it takes data that are already being collected and uses a computer algorithm to spit out a health score.
“At the three-hour point, out pops a prediction number,” said Dr. Anna Penn, a neonatologist at Packard Children’s Hospital and a co-author of the study, which was published this month in the journal Science Translational Medicine. “What this will likely be is one piece of information used among several others. It’s something that can be valuable for decision making.”
The Apgar score is useful to doctors for determining the broad treatment course of a baby born prematurely, or with other health problems. Babies born with a low Apgar score will probably be taken to a neonatal intensive care unit, or may even be transferred to a hospital able to provide more specialized care.
But in the Stanford study, the new method was far more accurate. For example, the Apgar score could predict whether a baby would develop a dangerous infection with 74 percent accuracy; the PhysiScore could make the same prediction with 97 percent accuracy.
Part of the reason for the increased accuracy may be the new scoring system’s use of a computer algorithm to assess raw electronic data.
The PhysiScore uses vital signs like a newborn’s heart rate and oxygen saturation, as well as how those vital signs change over time. These are all numbers that have long been available to doctors, but it’s been impossible for medical staff to constantly process all of the information and evaluate every infant based on the data collected.
In other words, for years hospitals have been collecting useful medical information on infants, but not taking full advantage of it, said Daphne Koller, a computer science professor in the Stanford University School of Engineering, who helped design the scoring system.
Researchers already are thinking about how similar scoring methods could be applied to other patients — people who have had heart attacks, for example, Penn said. With more hospitals keeping electronic medical records, there is a large amount of information automatically collected on patients, and much of it isn’t being put to use, she said.
It remains to be seen whether the PhysiScore will be reliable when applied to larger groups of infants. The babies in the Stanford study were born prematurely — six weeks or more short of a full-term, 40-week pregnancy — and weighed less than 4 pounds, 6.5 ounces.
Dr. Chris Retajczyk, a neonatologist at California Pacific Medical Center, said he will be paying attention to further studies of the new score. He said he’s done research into other scoring systems to improve on the Apgar and found them often more reliable. But they’re also overly complicated, he said. The appeal of Apgar is that it’s simple and quick — a score that shows up automatically on a medical monitor would be even better, he said.
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