07/03/91
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An effective treatment for a serious and common illness in infants -- called respiratory syncytial virus infection (RSV) -- can reduce by an average of seven days the hospital stay of infants with the most severe infections, Stanford University researchers reported in the July 4 issue of the New England Journal of Medicine.
RSV is estimated to cause respiratory tract infections in 80,000 to 100,000 infants and children each year. In about 5 percent of those children infected, the disease is so severe that they must receive help with breathing from a machine called a ventilator.
Over three years, 28 seriously ill infants who needed mechanical assistance to breathe participated in the Stanford study. Half of the babies received an antiviral drug called ribavirin and half received a placebo and standard care for the disease. On average, children receiving the drug required less time on ventilators, less oxygen, and less time in the hospital than their counterparts on placebo, the researchers reported.
Care for patients with severe RSV infections averages $5,000 per day, so in addition to improving the health of children, the therapy provides significant cost savings.
Of the 28 infants who participated, seven had underlying diseases that put them at risk of infection, while the other 21 infants were healthy before becoming infected with RSV. The researchers stressed that the study's results apply only to the children who were previously healthy, since the number of children with a combination of diseases was so small.
"Further work has to be done with children who have underlying diseases because they are more likely to die or have serious long-term problems as a result of RSV infection," said Dr. David Smith, associate professor of pediatrics and lead author of the report. The mortality rate for previously normal children is 1 to 5 percent, explained Smith, while up to 30 percent of children with underlying diseases may die from RSV infection. In the current study, one child of the 28 who participated died from complications of RSV.
Ribavirin is given in an aerosol form and breathed in by infected children. It was approved by the FDA in December 1986 for use in infants with mild to moderate RSV who are able to breathe effectively by themselves. Several studies had indicated that ribavirin treatment is successful in these patients, but no studies had been done to determine whether ribavirin is effective in more seriously ill children who require mechanical ventilation. Some physicians who tried the drug in conjunction with breathing machines reported problems with the drug crystalizing inside the equipment and blocking breathing tubes.
In view of such concerns, physicians at Stanford's Pediatric Intensive Care Unit felt ribavirin deserved more scrutiny in a carefully controlled clinical trial.
Smith emphasized that much of the credit for the success of the study belongs to the Stanford nurses and therapists who agreed to participate at a time when the use of ribavirin was considered controversial. Some medical centers had stopped using the drug when concerns arose that excess drug not absorbed by the patient is released into the atmosphere and could be hazardous to caretakers.
"We didn't want to needlessly and carelessly expose our staff to the drug," said Smith. "Our best assessment indicated that the risk to people taking care of children on ventilators is negligible because we use a system whereby the excess drug that's not breathed in by the child is filtered out before the air is released from the ventilator into the room."
Even so, any caretakers concerned about the risks could choose not to work with patients on ribavirin, explained staff nurse Lisa DiMercurio. "We always have enough staff that are willing and able to work with the drug," she said. "We were committed to finding out if the drug really worked."
Smith and colleagues are currently interested in determining whether ribavirin is also effective in children with underlying chronic disease by establishing a four or five institution collaborative study. "In three years we had only seven children at Stanford with RSV and chronic disease, so it would take us 15 years to answer the question," he said. "But with a combined effort, it should take only two or three years."
The FDA is considering whether to approve ribavirin as standard care for RSV patients who require ventilator support. The drug is currently widely available for such use, but requires informed consent before treatment can begin. Ribavirin is sold under the trade name Virazole by ICN Pharmaceuticals of Costa Mesa, Calif.
The study was supported by the Stanford Division of Intensive Care Pediatrics, a grant from the Stanford University Medical Center Technology Transfer Program, and a National Institutes of Health General Clinical Research Center grant. Smith's collaborators included Drs. Lorry Frankel, associate professor of pediatrics; Larry Mathers, assistant professor of pediatrics; Allen Tang, visiting fellow; Ronald Ariagno, professor of pediatrics; and Charles Prober, associate professor of pediatrics. --lbj--
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