Re: Effect of the endOclear ® Device on Biofilm in Endotracheal Tubes

1. The information regarding purpose, effectiveness, and previous testing were taken from the company website at the time of drafting the manuscript. It is stated that the device removes mucous, bacteria and biofilm. The relation to pneumonia quotes from the references on the company website. On reflection, it is the reference making the statement, and technically not the company. We also note the information on the website has changed since the drafting of this manuscript.

2. This was an observational study of a new intensive care unit respiratory practice, which included clearance of the endotracheal tube during the daily ventilator check. The therapist completed the manual questionnaire and placed it in a common, secured collecting area. We used the data sheets that were available. This is a potential source of bias, as we cannot determine whether the sheet was completed and turned in, nor can we confirm the cleaning.

3. Whether evaluating the change in tidal volumes (mean 29.9 mL) or the change in peak pressure (mean 0.39 cm H₂O), neither was dramatic or substantial in the context of the volumes and pressures ordinarily utilized in adult mechanical ventilation.

4. We could not mandate an exact number of minutes or seconds after the device was used for the exact reason described in the query; that the patient may be coughing, etc. and there was a need for the patient to return to baseline status.

5. We do think that biofilm stage is most likely related to an inherent patient factor that science has not yet elucidated. From previous work, the distribution of time of mechanical ventilation and stage of biofilm appears to be random (Chest, 2009). If one reviews Table 3 in this manuscript, the device group had more stage II biofilms than did the control group. The control group had more stage III biofilms which are more progressive and mature biofilms. This actually may support the company claim that it assists in removal, though not elimination, of some biofilm.

6. The study was not designed in any way to evaluate the impact of utilization of the device on the ability to liberate a patient from mechanical ventilation. The aims of the study were to evaluate the changes in pressure and the endotracheal tube (ETT) and to define the biofilm stages. No conclusions were drawn regarding extubation or successful spontaneous breathing trials.

7. A little over half of the treatments with the device resulted in removal of more than 1 mL of accretions, which is different from biofilm. The other half may be a reflection of effective removal of previous accretions, and continued use of the device could result in decreasing amounts of indwelling accretions with time. Regarding the change in resistance, we reported the mean difference, that is, the change between the pre and post measurements. The mean decrease was reported (1.67 cm H₂O), along with the standard deviation and range. We agree that the patient with a −17 cm H₂O change most likely noted an appreciable change in the work of breathing, but these data were not collected in this study.

8. We would like to clarify that the endOclear™ device is not U.S. Food and Drug Administration (FDA) approved. It is listed with the FDA as a Class 1 510K exempt device.

9. The scrapings from inside and outside the tube were separated. There is very poor understanding of the content of bacteria in ETT biofilms. This is our prime area of interest, although not the main focus of this study. We find it intriguing that across multiple studies, the bacteria in the ETT often are very divergent from those grown from quantitative samples. If there is no linkage and convergence, how can regulatory agencies claim that the tube and ventilator are the cause of a pneumonia? Indeed, if there are not microbiologic data showing a direct alignment of ETT bacteria and protected lung samples of bacteria, perhaps this pneumonia is not nosocomial at all. Although we do not have enough data from this limited study to make such strong claims, the finding certainly raises a most interesting question.

10. There was a difference in the number of pneumonias in the two groups, but, as seen in Table 2 in the paper, the difference was not statistically significant. We used the U.S. Centers for Disease Control and Prevention Guidelines for PNEU2. We did not exclude patients with emergency intubation, intubation in the field, aspiration, etc., as is often done when collecting numbers for ventilator-associated pneumonia (VAP). Because this was not a study regarding VAP, we did not eliminate these patients and recognize that these are confounding factors. However, we believe that although national and institutional cases of VAP continue to decrease, the problem of pneumonia in the critical care patient has not been eliminated.