Between 16 and 58 percent of the patients in pediatric intensive care units (PICU) don't need to be there, researchers concluded in last week's Journal of the American Medical Association. These patients consume between 5 and 35 percent of all patient-days of pediatric ICU care.

The appropriate use of intensive care units has been under close examination for the past few years because treatment in such a unit is so expensive. Twenty percent of all hospital charges, equivalent to 1 percent of the gross national product, are consumed by critical-care medicine.

Previous studies showed that more than three quarters of the admissions to adult medical-coronary care units were only monitored and did not receive intensive therapies. One study of PICUs concluded that more than a quarter of the patients did not receive therapies that couldn't be provided elsewhere in the hospital.

Researchers at George Washington University School of Medicine and the Children's Hospital National Medical Center, both in the District, examined PICU admissions of 1,668 patients in eight university or university-affiliated hospitals and whether they stayed there longer than was necessary.

Even when children needed the intensive care initially, they tended to stay there too long, so that during the last days in the PICU, they did not need, and did not receive, intensive care. Because they were in the PICU, however, they continued to be charged for the most expensive care a hospital can provide.

The researchers developed their own scale for rating the efficiency of a PICU and found that the efficiency with which the eight hospitals used their units ranged from 54.7 percent to 89.4 percent.

"This analysis has national importance for the containment of pediatric intensive care costs," the authors concluded. They said that criteria for exactly when a child should be admitted to a PICU is not precise and that there is a "threshhold of uncertainty" among physicians.