Among intensive care unit patients who require mechanical ventilation, use of a silver-coated endotracheal tube resulted in reduced incidence of pneumonia associated with ventilators, according to a report in the August 20 issue of JAMA.1
Ventilator-associated pneumonia is associated with longer hospital stays, increased health care costs and infection with antibiotic-resistant pathogens, according to background information in the article. It is likely to develop when pathogenic bacteria colonize the aerodigestive tract or when patients breathe out contaminated secretions. “Prevention strategies often focus on modifiable risk factors for colonization and aspiration and can successfully reduce ventilator-associated pneumonia rates, but no single strategy completely eliminates ventilator-associated pneumonia,” the authors write. “Adherence to prevention guidelines is variable due to costs and lack of education, resources and leadership.”
Silver has displayed antimicrobial activity in the laboratory and has blocked the formation of harmful pathogens on ventilator tubes in animal models. Marin H. Kollef, M.D., of the Washington University School of Medicine, and colleagues in the NASCENT Investigation Group report on a randomized controlled trial involving patients at 54 centers expected to require mechanical ventilation for 24 hours or longer. Between 2002 and 2006, 2,003 patients were randomly assigned to undergo intubation with either a silver-coated tube or a similar tube that was not coated.
Of 1,509 patients who were intubated for 24 hours or longer, 4.8 percent of those with silver-coated tubes developed ventilator-associated pneumonia, compared with 7.5 percent of those with uncoated tubes—a 35.9 percent relative reduction in risk. Among 1,932 patients who were on ventilators for any length of time, the silver coating was associated with a 34.2 percent relative reduction in risk of developing pneumonia (3.8 percent of those with silver-coated tubes vs 5.8 percent with uncoated tubes).
In addition, the silver-coated tubes were associated with a delayed occurrence of ventilator-associated pneumonia. No differences were seen between the two groups in median (midpoint) duration of intubation, length of stay in the intensive care unit (ICU) or in the hospital, death rates or frequency and severity of adverse events.
“In conclusion, the results of this large, randomized, multicenter study demonstrated that the silver-coated endotracheal tube significantly reduced the incidence of microbiologically confirmed ventilator-associated pneumonia and had its greatest benefit during the peak time of ventilator-associated pneumonia occurrence, without any notable adverse events,” the authors conclude. “The silver-coated endotracheal tube appears to offer a unique approach because it is the first intervention that becomes user-dependent after intubation, requiring no further action by the clinician.”
“Based on the results of this trial, should clinicians reconsider guidelines for ventilator-associated pneumonia prevention and use a silver-coated endotracheal tube in all patients requiring intubation and mechanical ventilation in the ICU?” writes Jean Chastre, M.D., of the Groupe Hospitalier Pitie-Salpetriere, Paris, in an accompanying editorial2.
“The answer is probably yes for the subset of patients at very high risk of developing early-onset ventilator-associated pneumonia, such as neurologically impaired patients or trauma patients, because the greatest effect of the intervention appeared to occur during the first 10 days of mechanical ventilation and was clinically relevant, with minimal effect on clinician workload,” Dr. Chastre writes.
“Important uncertainties exist regarding the exact benefit of silver-coated endotracheal tubes,” Dr. Chastre concludes. “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.”
1. JAMA. 2008;300:805-813.
2. JAMA. 2008;300:842-844.