Investigating the failure to aspirate subglottic secretions with the Evac endotracheal tube

BACKGROUND: Aspiration of subglottic secretions is a widely used intervention for prevention of ventilator-associated pneumonia. However, using the Hi-Lo (R) Evac enclotracheal tube (Hi-Lo Evac; Mallinckrodt; Athlone, Ireland) (Evac ETT), dysfunction of the suction lumen and subsequent failure to aspirate the subglottic secretions are common. Our objective in this study was to determine the causes of suction lumen dysfunction experienced with the Evac ETT. METHODS: We studied 40 adult patients intubated with the Evac ETT. In all cases for which dysfunction of the suction lumen was observed, the subglottic suction port was examined visually using a flexible bronchoscope. RESULTS: Dysfunction of the suction lumen occurred in 19 of 40 patients (48%). In 17 of these (43%), it was attributed to blockage of the subglottic suction port by suctioned tracheal mucosa. CONCLUSION: Evacuation of subglottic secretions using the Evac ETT is often ineffective due to prolapse of tracheal mucosa into the subglottic suction port.