Abstract
To the Editor:
I
I also thank the authors for their agreement (on further reflection) that the Company has never represented that the use of any of our devices decreases the likelihood of ventilator-associated pneumonia (VAP). We have many references on many different aspects of caring for ventilated patients on our website. Clearly, not all of these references will represent the Company's position on any specific issue, nor should they, but the references are important in the interest of fairness and debate. And yes, we do alter the website content regularly to present new information of interest in the field.
To not know whether the process or procedure being investigated was in fact performed according to the study design remains the most glaring and significant shortcoming of the study and invalidates any conclusions drawn regarding the value of routine daily cleaning of the endotracheal tube (ET).
Also the authors' response confirms that the timing of pre- and post-procedure measurements was not controlled in any fashion, which may obscure significant findings.
If we do not know whether the procedure was actually performed, or when it was performed in relation to extubation and biofilm stage assessment, how can any reasonable conclusion be drawn about the results in the two groups? This was a small study, and calculations of statistical significance were either not performed or simply not presented.
One of the stated aims of the study was to evaluate changes in pressure. Here, I believe the authors miss the point of the criticism I made. If the patient ventilator mode was pressure controlled, clearing of an ET would not be expected to change the peak pressure but could result in larger tidal volumes. However, if the ventilator was volume controlled, clearing of the ET would not change the tidal volume but could reduce the peak pressure. To not stratify by patient ventilator mode makes assertions about the effect of the cleaning device on tidal volume and peak pressure unreliable.
I thank the authors for correcting the information about the FDA approval of the device.
What we do know is that if a pneumonia-causing microorganism that is recovered from the lungs is also in the ET biofilm, the patient is more likely to suffer treatment failure or pneumonia recurrence. “The idea of bacterial survival on ETT biofilm as a pathogenic mechanism for microbial persistence and impaired response to antibiotic therapy highlights the importance of discovering new strategies focused in the removal of biofilm from the ETT (Gil-Perotin S, Ramierez P, Marti V, et al. Implications of endotracheal tube biofilm in ventilator-associated pneumonia response: A state of concept. Crit Care 2012;16:R93).
Although we understand the VAP diagnosis bias that may have been introduced by West Virginia University, an overall VAP rate of 42.5% in all intubated patients at any institution measured by whatever criteria is an exceptionally high number.