(704d) Assessment of Nanomodified Endotracheal Tubes in a Bench Top Airway Model

Ventilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, 8 to 28% of all patients receiving mechanical ventilation with endotracheal tubes (ETT) develop VAP. This disease is especially hard to diagnose and treat leading to a high mortality rate. Cost effective ETT that are resistant to bacterial infection would provide a necessary solution to this problem. In addition to bacterial resistance, ETT with magnetic nanoparticles could aid in the diagnosis of VAP allowing physicians to locate infections with greater accuracy.

The objective of this study was twofold, first to develop strategies to decrease bacterial infection on currently used ETT and secondly to develop better methods to assess in vitro infection of ETT. In preliminary tests, nanomodified polyvinyl chloride (PVC) endotracheal tubes have been shown to be effective at reducing bacterial infection. Moreover preliminary results demonstrated promise towards decreasing bacterial infection using both magnetic nanoparticles and selenium coated ETT. This study also sought to evaluate the bacterial resistance of these ETT more effectively by creating a bench top airway model, which can more accurately model the fluid effects that ETT are exposed to in vivo.

The airway model designed to test ETT under airway conditions has two plexiglas chambers representing the oropharynx and the lungs, a tube representing the trachea and finally an intricate pumping system to both contaminate the oropharynx with bacteria and accurately simulate compliance and resistance within the lung model. ETTs were connected to a ventilator and extended from the oropharynx into the trachea subjecting these tubes to both mechanical ventilation and continuous bacterial contamination. In addition, the study examined dual gas flow conditions and their effect on bacterial contamination of ETT.

In no less than three separate trials in the airway chamber, each ETT was tested for its effectiveness at the reduction of bacterial growth within the airway. Special attention was given to the long-term effects on the ETT by including a study that lasted longer than ten days. Both the bacterial proliferation in the two chambers and on the ETT itself were carefully analyzed. This specialized testing yielded valuable information on the efficacy of nanomodified ETT in airway conditions and provided further evidence to determine if nanomodified ETT are a valid solution to VAP.