Current methods for secretion removal in the upper airways of the ICU ventilated patient
In mechanically ventilated patients, an artificial airway (intubation tube) is present either as an endotracheal tube (ETT) or tracheostomy tube (TT). On these tubes a cuff (a small balloon) is placed and inflated, which allows the mechanical ventilator to control or support the patients breathing. But the inflated cuff introduces the following issues:
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Patients are not able to adequately cough up secretions below the cuff (A). Therefore, endotracheal suctioning (ET or Tracheal suctioning) is an important activity in reducing the risk of consolidation and atelectasis that may lead to inadequate ventilation and the risk of pneumonia infection, also known as ventilator-associated pneumonia (VAP) [9,10,11,18].
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Underinflation of the tracheal cuff frequently occurs in critically ill patients and represents a risk factor for microaspiration of contaminated oropharyngeal secretions and gastric contents into the lower respiratory tract (so-called subglottic secretions) which accumulate above the cuff (B). This can also result in VAP [7,8] if not removed by suctioning.
The occurrence of VAP has an undeniable impact. It increases the duration of mechanical ventilation (MV) and the length of stay in intensive care unit (ICU) by a factor of 2 to 3 [20], as well as incurring an increase in antibiotics administered and hospital expenditures. The attributable mortality of VAP remains controversial: recent published studies (analysis from a large-scale database or meta-analysis based on VAP prevention studies) estimated it to range between 4.4% and 9% [20]. Thus, a prevention policy aiming to reduce VAPs remains an important element of the overall management for patients admitted to ICUs and requiring MV.
As the intubated patients are unable to adequately cough up secretions, tracheal suctioning has become an important activity in reducing the risk of consolidation and atelectasis that may lead to inadequate ventilation and VAP. But, the procedure is associated with complications and risks including [10,17,19]:
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Tracheal or upper airway bleeding (the tube grips onto the trachea and “rips” it)
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Increased risk of infections (as all the secretions are not removed – especially not thicker secretions and secretions above the ETT tip and below the cuff)
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Atelectasis (complete or partial lung collapse due to PEEP loss)
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Hypoxemia (also referred to as desaturation due to FiO2 loss)
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Cardiovascular instability (suctioning stresses the patient)
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Elevated intracranial pressure (not optimal for neuro ICU patients)
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Lesions in tracheal mucos (bleeding)
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Stimulated coughing (suctioning stresses the patient)
As the primary route of bacterial entry into the lower respiratory tract is via aspiration of bacteria-contaminated secretions which accumulate above the cuff, the focus has increased on removing secretions above the cuff and ensuring optimal cuff pressure to prevent aspirations of bacterial-contaminated secretions. Currently, the best options are:
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Subglottic secretion drainage (SSD) has been proposed to be included in the bundles of VAP prevention. Nevertheless, the SSD requires specific intubation tubes including a separate dorsal lumen that opens immediately above the ET tube cuff [20,21]
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Maintaining the cuff pressure, in order to secure that the tube cuff-pressure should be sufficiently high to prevent bacterial entry into the lower respiratory tract in order to reduce the appearance of VAP. On the other hand, tracheal-tube cuff pressure should not be too high to avoid vascular compromise of the trachea, which could result in tracheomalacia and even tracheal necrosis[9]
However, these options still come with issues:
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Subglottic secretion drainage (SSD) requires extensive workload as the nurse or respiratory therapist multiple times a day have to drainage the separate dorsal lumen above the intubation tube cuff, and if not drained frequently, the tube will block with thick and hardened secretion, making subglottic secretion removal in-efficiently and will allow bacterial entry into the lower respiratory tract [27].
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Maintaining the cuff pressure manually requires extensive workload as the nurse or respiratory therapist multiple times a day have to check and adjust the cuff pressure, and if not maintained frequently, the cuff pressure will slowly deflate and will allow bacterial entry into the lower respiratory tract [9].
As shown above, the tools today for Tracheal and Subglottic secretion removal:
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Comes with complications and risks including bleeding, infection, atelectasis, hypoxemia, cardiovascular instability, elevated intracranial pressure, and may also cause lesions in the tracheal mucosa, which will increase the need for continuous ET suctioning [17,18,19]
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Is described by patients as painful and uncomfortable and may result in a choking sensation initiating a violent cough [14], and also causes an unpleasant sensation that the lungs are actually being suctioned into the catheter,
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Discomfort and the potential complications of suctioning may intimidate inexperienced nurses [8],
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Have shown to be in-efficient if the secretion is thick, making secretion removal in-efficiently and will allow bacterial-contaminated secretions develop into VAP [17]
However, recently the TrachFlush device has been introduced to the market. TrachFlush™ allows for continuous and automatic maintenenance of cuff pressure, blocking microaspirations, potentially reducing the VAP and infection rate [4,5]. Additionally, TrachFlush allows the nurse or respiratory therapist to remove secretion below and above the cuff with the push of a button, and without suctioning [1,2,3].