Vol. 19 • Issue 8 • Page 26
photo / courtesy Omneotech
Clearance of obstructing secretions from the artificial airway of patients receiving mechanical ventilatory support is a simple task for patients with tracheostomy tubes equipped with inner canulas. However, removing luminal secretions from an endotracheal tube (ET) is considerably more problematic.
Most clinicians think of an ET as being obstructed by secretions only when the obstruction is severe enough to present in its most dramatic form. Yet, secretion-related ET obstruction is a spectrum of disease varying in severity from partial to complete, and it results in clinical manifestations that vary accordingly.
How do ET secretions manifest clinically? They can present in three ways: failure to wean from mechanical ventilation, sudden airway obstruction, and ventilator-associated pneumonia (VAP). The first two clinical presentations are related to the mass effect of the secretions, whereas the third is dependent on their microbiological content and the infectivity of biofilms.
Partially obstructing secretions increase airflow resistance and imposed work of breathing through the ET, which can delay weaning from mechanical ventilation. Partial ET obstruction is a frequently occurring clinical phenomenon that is underappreciated due to its insidious presentation. If a partial ET obstruction progresses to a completely or near-completely obstructed ET, also commonly referred to as a plugged tube, removal of the offending plug ameliorates or resolves the patient’s respiratory distress. Timely intervention can avert a cardiopulmonary arrest episode, along with a variety of resultant ischemic insults.
Bacterial biofilm within the ET has been implicated in the pathogenesis of VAP, as a result of biofilm clumps becoming dislodged from the ET and propelled into the lungs. Removal of bacteria-laden ET secretions may therefore help reduce the size of the bacterial reservoir from which the patient is at risk for being inoculated. This is the basic premise behind the recommendation by the Centers for Disease Control and Prevention stating that condensate pooled in the ventilator tubing should be drained away from (rather than toward) the patient, in order to reduce the risk of aspiration and inoculation by contaminated secretions.
Strategies to manage ET secretions
Humidification of the breathing circuit is an important component of a comprehensive approach to minimizing the accumulation and clinical impact of ET secretions, but it is not a panacea. Despite practicing acceptable humidification strategies, several clinical thought leaders have reported that ET narrowing due to secretion accumulation was a common occurrence in their own intensive care units.
Suctioning via a suction catheter or through a bronchoscope, sometimes accompanied by saline irrigation, is common practice to attempt to clear ET secretions. However, under experimental conditions, only 26 percent and 46 percent of ET secretions were removed by 12 French and 18 French suction catheters, respectively. Use of the larger suction catheter also resulted in considerable loss of PaO2.
Saline irrigation has been used as a method for diluting inspissated secretions, although this practice has been shown to dislodge a greater quantity of bacteria from the ET than that dislodged by passage of a suction catheter. Instillation of saline through the ET, which effectively translates into an iatrogenic aspiration episode, is counter to the basic premise of draining contaminated fluids away from the patient, as recommended by the CDC.
Exchange of the ET, emergent extubation with reintubation, and performance of a tracheostomy are the most dramatic approaches to dealing with obstructing ET secretions that cannot be cleared by other means. These invasive interventions re-establish airway patency and may be life-saving, but they also may result in a variety of serious complications.
The CAM Rescue CathTM, a new device with the dual ability to suction or mechanically remove ET secretions, is a less invasive alternative to extubation with reintubation, ET exchange, or tracheostomy. The catheter is equipped with a standard airway suction port, but it is narrower and more rigid than standard 14 French suction catheters. Its unique cleaning assembly expands at the distal tip of the ET and effectively removes secretions more effectively than by suctioning alone and without saline irrigation.
The intervention takes seconds to perform, and no complications have been reported. It may avoid significant risks to the patient, institutional costs, and potential liability to the practitioner and institution associated with invasive airway procedures performed for ET obstructions. Furthermore, clearance of partial ET obstructions with reduction of imposed work of breathing may expedite weaning from mechanical ventilation, a desirable goal that could affect a significant percentage of intubated patients and improve ICU throughput.
Orlando Morejon, MD, is president of Omneotech®, Tavernier, Fla., developer of the CAM Rescue CathTM.