Ventilator associated pneumonia (VAP) is a serious and costly clinical problem. Patients receiving mechanical ventilation over 24 hours have an increased the risk of contracting VAP, which is associated with high morbidity, mortality and medical costs. VAP is especially difficult to diagnose in children because of non-specific clinical and radiographic signs as well as a lack of sensitive diagnostic methods. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would help to prevent this problem. The objective of this study was twofold, first to develop an in vitro airway model to simulate the dynamic conditions of the pediatric airway and secondly to assess in vitro bacterial adhesion or biofilm formation on clinically used ETTs and nanomodified (with surface features less than 100 nm in at least one direction) ETTs under these dynamic conditions. In preliminary tests, nanomodified polyvinyl chloride (PVC) ETTs have been shown to be effective at reducing bacterial adhesion. To evaluate the bacterial resistance of these ETTs more effectively, this study designed a bench top airway model to create a similar environment to the natural flow system that ETTs are exposed to in vivo.

The airway model designed to test ETTs has two plexiglas chambers representing the oropharynx and the lungs, a tube representing the trachea and finally an intricate pumping system to the oropharynx with bacteria flow and to the lung with simulated compliance and resistance. Endotracheal tubes will be connected to a ventilator and will pass through the oropharynx chamber into the trachea and will be observed under both mechanical ventilation and continuous contamination within the artificial flow system. In no less than three separate trials in the airway chamber, each ETT will be tested for its effectiveness at the reduction of bacterial growth within the airway by sampling from both lung and oropharynx chambers during continuous operation. Special attention will be given to the long-term effects on the ETT by including a study that lasts longer than five days. Both the bacterial proliferation in the two chambers and on the ETT itself will be carefully analyzed. This specialized testing should yield valuable information on the efficacy of nanomodified ETT in airway conditions and will provide further evidence to determine if nanomodified ETTs are a valid solution to VAP.