Efficacy of silver nanoparticles-impregnated external ventricular drain catheters in patients with acute occlusive hydrocephalus.

INTRODUCTION: Catheter-associated infection of cerebrospinal fluid (CSF) is a potentially life-threatening complication of external ventricular drainage (EVD). The purpose of this pilot study was to address the efficacy of silver-impregnated EVD catheters in neurological and neurosurgical patients requiring external CSF drainage due to acute occlusive hydrocephalus. METHODS: Nineteen consecutive patients were enrolled in the treatment arm of the study and data were prospectively recorded for these patients. The control group consisted of 20 patients for whom data were retrospectively assessed. CSF samples were drawn at least three times a week and routine bacterial cultures and CSF analyses were done according to standard protocols. The primary endpoint of the study was the occurrence of catheter-associated ventriculitis (CAV) proven by positive CSF culture. Secondary endpoints were bacterial colonization of the catheter tip and CSF pleocytosis. RESULTS: In 20 control patients, 5 CAVs were microbiologically diagnosed. In contrast, no positive CSF cultures were found in the treatment group. This difference was statistically significant (P < 0.05). All CAVs occurred later than day 10 after catheter placement. Colonization of the catheter tip was found in 6 patients in the control group and in 5 patients in the treatment group (not significant). CONCLUSIONS: This pilot study indicates that EVD catheters impregnated with silver nanoparticles might be a new option for preventing CAV in neurocritical care patients, and therefore evaluation in a large prospective randomized study is warranted.

Silver segregation and bacterial growth of intraventricular catheters impregnated with silver nanoparticles in cerebrospinal fluid drainages.

OBJECTIVES: Intraventricular catheters impregnated with silver nanoparticles are developed to reduce catheter-associated infections in cerebrospinal fluid (CSF) drainages. Silver released from these new catheters should have an anti-microbacterial effect. This study examines the silver ion release and a potential effect of bacterial growth in an in vitro experiment. METHODS: Seven original silver-coated ventricle catheters were rinsed thoroughly with an artificial CSF for 6 days. The collecting containers were replaced every 24 hours. In these samples, ion concentrations of silver were determined via trace analysis through atomic absorption spectroscopy. Furthermore, a bacterial growth was conducted on silver-impregnated and non-impregnated catheters. RESULTS: In none of the samples, a concentration of silver ions could be detected. For Staphylococcus aureus, a slightly decreased bacterial growth could be observed with silver-impregnated catheters. DISCUSSION: There is no risk of a toxic effect due to silver release into the CSF. However, the in vivo antibacterial effect has to be further investigated. We recommend clinical trials to prove the oligodynamic and anti-microbacterial effects of silver-impregnated ventricular catheters.