Blowing the pipes clean works!

We would like to congratulate Gentile and Siobal on their review article concerning the recent advances in equipment for the treatment of ventilator-associated pneumonia,1 in which they reported different techniques to clear the subglottic secretions that accumulate during intubation. At the time of extubation, they described applying a positive pressure gradient just prior to cuff deflation. The cuff is then deflated and the endotracheal tube removed. Theoretically, any secretions would be pushed from the subglottic space by the escaping gas into the oropharynx where they can be suctioned away. They considered that further investigations into this technique are warranted. WeinvestigatedwhetherusingPEEPduring cuff deflation and extubation might be advantageous.2 We designed a bench-top study to compare the ability of a tracheal suction catheter, adjusting the PEEP setting on the ventilator or squeezing a selfinflating bag to minimize aspiration during cuff deflation and extubation. We intubated a model trachea and attached the proximal end of the endotracheal tube to a mechanical ventilator. Next we placed 10 mL of water above the inflated cuff and then applied one of a number of test protocols. The volume of water “aspirated” into the lungs was determined by weighing the apparatus before and after extubation. In this model, a PEEP level of 35 cm H2O was the most efficacious (mean SD pulmonary aspiration volume 1.6 0.1 mL), when compared to the use of tracheal suction catheter (mean SD pulmonary aspiration volume 8.2 0.1 mL) or squeezing a self-inflating bag (mean SD pulmonary aspiration volume 5.7 1.2 mL). There was an 81% reduction in mean pulmonary aspiration volume using this level of PEEP, compared to a tracheal suction catheter (P .001). We found having a high level of PEEP was the key to the efficacy of this technique. Although, a high pressure can be generated by squeezing a self-inflating bag, the flow rate cannot be sustained long enough to prevent considerable aspiration as the bag quickly empties. Our study supports the hypothesis generated by Bahhady et al that the application of PEEP is protective against aspiration, compared to the use of a tracheal suction catheter during extubation.3 Subsequently, in a survey of routine practice in critical care units in the United Kingdom of 532 healthcare workers, we found that 87% of respondents used a tracheal suction catheter, 6% squeezed a self-inflating bag, and only 1.3% adjusted the PEEP setting on the ventilator during extubation.2 In light of these findings, we now plan to instigate a clinical trial to confirm the clinical efficacy of this technique, in the hope that it will be used more widely.