TUESDAY, Aug. 19 (HealthDay News) -- The use of silver-coated endotracheal tubes reduced the risk of pneumonia among intensive-care patients on ventilators, a U.S. study found.

Ventilator-associated pneumonia can lead to longer hospital stays, increased costs, and infection with antibiotic-resistant bacteria. Currently, no single prevention strategy eliminates ventilator-associated pneumonia, according to background information in the study.

Previous laboratory and animal tests showed that silver has antimicrobial properties and blocks the formation of harmful bacteria on ventilator tubes.

In this study, Dr. Marin H. Kollef, of the Washington University School of Medicine, and colleagues looked at 2,003 patients randomly assigned to undergo intubation with either a silver-coated tube or an uncoated tube.

Of 1,509 patients who were intubated for 24 hours or longer, ventilator-associated pneumonia developed in 4.8 percent of those with silver-coated tubes and in 7.5 percent of patients with uncoated tubes -- a 35.9 percent relative reduction in risk.

Of 1,932 patients who were on ventilators for any length of time, pneumonia developed in 3.8 percent of patients with silver-coated tubes and in 5.8 percent of patients with uncoated tubes -- a 34.2 percent relative reduction in risk.

The researchers also found that silver-coated tubes delayed the onset of pneumonia.

The findings are published in the Aug. 20 issue of the Journal of the American Medical Association. The study, including design, data collection, statistical analysis and manuscript preparation, was supported by a research grant from C. R. Bard Inc.

The study results suggest that silver-coated tubes may benefit patients at high-risk of developing early-onset ventilator-associated pneumonia, such as neurologically impaired patients and trauma patients, Dr. Jean Chastre, of the Groupe Hospitalier Pitie-Salpetriere, in Paris, wrote in an accompanying editorial.

"Important uncertainties exist regarding the exact benefit of silver-coated endotracheal tubes," Chastre noted. "Consequently, silver-coated tubes should not be viewed as the definitive answer for ventilator-associated pneumonia prevention, and, until additional data confirm the clinical effectiveness and cost benefit of these devices, their issue should be restricted to high-risk patients treated in ICUs with benchmark value-based infection rates that remain above institutional goals despite implementation of a comprehensive strategy of usual preventive measures to prevent ventilator-associated pneumonia."

More information

The American Thoracic Society has more about mechanical ventilation.