We know that the risk for infection increases the longer a patient is mechanically ventilated. There are probably several mechanisms that contribute to this risk, but certainly microaspiration or leakage of secretions around the tracheal tube cuff is a primary one.
With increasing time on the ventilator and time in the ICU, a patient’s secretions become colonized, and the ability to precipitate pneumonia from microaspiration is a real phenomenon. Venilator-associated pneumonia also is part of a much broader problem with a large impact on the health care system: post-intubation or post-operative pulmonary complications, sometimes called PIPC. Post-intubation pulmonary complications are surprisingly common and are associated with significant mortality. As with VAP, microaspiration may be the primary cause of or may further exacerbate a wide range of these complications.
The problem needs to be attacked with a multitude of strategies, from oral care and oral hygiene, to keeping the head of the bed elevated, to managing sedation in the ICU, and striving for earlier ventilator weaning and earlier removal of the endotracheal tube.
One of the strategies that has been highly productive has to do with removing secretions from above the endotracheal cuff. Subglottic secretions drainage has been shown to reduce VAP by up to 75 percent. When we look at the data, combining subglottic secretions drainage with endotracheal tubes that feature a taper-shaped cuff design may be even more effective in reducing leakage past the cuff.
The way most endotracheal cuffs are designed hasn’t changed since the mid-1970s. Because they’re designed to be larger than the trachea, they tend to form folds or micro-channels when they’re inflated in the trachea. Those micro-channels allow fluid to move past the cuff and down into the lungs. Their ability to seal out fluid has marked limitations.
What is revolutionary about a taper-shaped tube cuff is that it allows the cuff diameter to match the diameter of the trachea at some point along the cuff. That reduces the micro-channels at the sealing zone, which markedly improves sealing characteristics and offers a 90 percent reduction in microaspiration as compared to a traditional tube cuff.
There are significant opportunities for the medical community to advance the prevention of VAP and PIPC. Can we eliminate them? Perhaps not, but we have the ability with existing technologies to change the game and make some major in-roads.
Douglas M. Hansell, MD, MPH is chief medical officer and vice president of respiratory and monitoring solutions for Covidien, Boulder, Colo.
