A 48-Hour Comparison of 4 Subglottic Suction Endotracheal Tube Models in Ex-Vivo Porcine Tracheas

Abstract

Background: Endotracheal tube (ETT) intubation is the single largest risk factor for the development of a ventilator-associated pneumonia (VAP) in the ICU. ETT intubation compromises the cough reflex, mucocilliary clearance, injures the tracheal epithelial surface, provides a direct conduit for rapid access of bacteria, and provides a surface for the formation of biofilms. The use of single suction port subglottic suction endotracheal tubes (SSETT) for the prevention of VAP has been endorsed by many professional medical societies. Numerous random controlled trials demonstrate that SSETTs reduce the duration of mechanical ventilation, length of ICU stay, antibiotic treatment, and delays the onset of VAP. There are several industry approved single port SSETTs used clinically with reports of variable performance outcomes. We aim to evaluate the performance of two brands of single port SSETTs in a trachea model over a clinically relevant period, under manufacturer recommended guidelines. Methods: Five porcine tracheas which were set up in simulate a 30-degree semi-recumbent position. The study apparatus was designed to mimic a realistic clinical setting to observe the functionality of various subglottic endotracheal tubes over a period of at least 48 hours. The porcine tracheas mimic anatomic structures in a patient and tissues provide a more realistic model when compared to clear acrylic tubes. Positioning each ETT such that the subglottic region above the cuff balloon came into direct contact with the posterior tracheal wall simulates real clinical positioning of the tube. This helps to also simulate the phenomenon that as fluid is aspirated the mucosa would be drawn closer to the suction lumen and would likely increase the risk of occlusion. Results: A control model using a tapered polyurethane cuffed tube without subglottic suction was established and demonstrated 95% of solution leaked pass the cuff and was recovered over 51.5 hours. Conclusions: The findings in the four other models involving two brands of SSETTs, revealed that both brands experienced suction failure due to herniation of tissue into the single suction port. This was observed at manufacturer recommended intermittent and continuous suction pressure settings and both single suction port SSETTs were unable to prevent fluid accumulation above their respective cuffs.