A tracheostomy tube may be either "cuffed" or "cuffless (uncuffed)." A cuffed tracheostomy tubes has a balloon-like feature at the distal end of the tube. There are three main types of cuffs: low-pressure cuffs, low-volume cuffs and foam-filled cuffs. The cuff can be inflated or deflated with air or water depending on which type of cuff is present.
Patients with COVID-19 with tracheostomy are a high risk for aerosolizing A cuffed tracheostomy tube with the cuff inflated allows for a closed system and is the most likely to prevent cross-contamination of staff, equipment, other patients.
For more information on patients with COVID-19 and tracheostomy and mechanical ventilation please see our article, COVID-19 Tracheostomy and Mechanical Ventilation.
Cuffs with a high volume have low-pressure and are called "high volume low-pressure cuffs." As per manufacturer recommendation, Bivona Aire-Cuf (Smiths Medical North America, Dublin, Ohio) and Shiley cuffs (Covidien, Mansfield, Massachusetts) should be inflated with air only.
High volume-low pressure cuffs are generally dual cannula tracheostomy tubes. Dual cannula tubes have an inner cannula and an outer cannula. Because of the large volume, a larger surface area is in contact with the tracheal wall, which lowers the incidence of damaging the tracheal mucosa. However, these cuffs occupy a large amount of space when the cuffs are deflated during ventilator weaning. The resistance from the cuff may result in difficulty exhaling through the upper airway when the cuff is deflated or difficulty tolerating a speaking valve or cap.
High volume-low pressure cuffs are the most frequently used tracheostomy tube in the US.
Cuffs with a low volume have a high pressure and are called "low volume high-pressure cuffs." These are single cannula tracheostomy tubes such as the Bivona Tight to Shaft (TTS). As per manufacturer recommendations Bivona TTS tracheostomy tubes should be filled with sterile water only. If filled with air, the cuff will deflate over time due to gas impermeability.
Low volume high-pressure cuffs are just as the name describes. There is a smaller surface area that is in contact with the tracheal wall, resulting in a high pressure seal. Although the seal may be more effective for positive pressure ventilation to be maintained, there may be a higher risk of tracheal injury. However, when the cuff is deflated, there is no resistance to airflow through the upper airway and essentially act as a cuffless tracheostomy tube.
These may be a good option for patients who are off mechanical ventilation during the day, and on nocturnal ventilation and requiring a cuffed tube. These patients should have limited secretions if using a TTS tracheostomy tube since there is no inner cannula. The inner cannula can be removed if there is a blockage from mucous, whereas if the tube does not have an inner cannula and it becomes blocked the entire tube may need to be removed.
Foam filled cuffs are made out of foam material to prevent injury to the tracheal mucosa for patients with tracheal abnormalities. When the foam filled tracheostomy tube is in place, the pilot tube remains open to the atmosphere, so the intracuff pressure is at ambient levels. The open pilot port also permits compression and expansion of the cuff during the ventilatory cycle. The degree of expansion of the foam is a determining factor of the degree of tracheal wall pressure. As the foam further expands, lateral tracheal wall pressure increases. When used properly, this pressure does not exceed 20 mm Hg (27 cm H2O) (Hess, 2014).
Because a foam filled cuff cannot be completely deflated it is an absolute contraindication to speaking valve and capping use. There is also risk for spontaneous reinflation with a foam filled cuff.
Foam filled cuffs are not used frequently. They are typically used in patients with known tracheal damage due to the cuff.
Regardless of the type of cuffed tracheostomy tube, the purpose of the cuff is to maintain the air delivered from the mechanical ventilator to the lungs. It may be necessary to keep the cuff of the tracheostomy tube inflated so all the air delivered from the ventilator goes to the lungs and then back to the ventilator on exhalation to be measured and monitored. This is often the case during the acute disease process. Once the patient is stabilized, the cuff may be deflated or the tube may be changed to a cuffless tracheostomy tube. Even patients on mechanical ventilation may be candidates for deflating the cuff or cuffless tracheostomy tubes.
It is a common misconception that the cuff of the tracheostomy tube prevents aspiration. The definition of aspiration is any material that passes below the level of the vocal folds. The cuff is located below the level of the vocal folds. So any material that reaches the cuff has already been aspirated. The cuff does not form an impenetrable seal and therefore aspirated material that reaches the cuff, passes around the cuff and into the lower airways. There are some patients who have excessive secretions and poor airway protection in which the cuff can help to reduce the amount of secretions that enter the lungs.
Some research has shown that an inflated cuff may cause impaired swallow physiology. The cuff may reduce the ability for the larynx to elevate, which is important for protecting the airway from aspiration. The cuff may also reduce sensation through the oropharynx, impair subglottic pressures for swallowing, and impair the natural cough reflex. Increased cuff pressures may actually make it more difficult to elicit a swallowing reflex (Ametheiu, 2012).
On rare occasions, a patient may have a severe swallowing impairment with inability to clear the airway for airway protection. These patients are unable to tolerate cuff deflation noted by a significant change in vital signs or respiratory distress during cuff deflation. An inflated cuff can provide a means of bypassing the secretions that are unable to be cleared during cuff deflation through the upper airway.
A physician order is needed prior to cuff deflation. Always educate the patient on any procedure to reduce anxiety and improve cooperation. Staff should wear appropriate PPE during cuff deflation.
Cuff deflation is a aerosol generating procedure and is particularly high risk for spreading SARS-CoV-2 (the virus that causes COVID-19) when patients are on mechanical ventilation. For patients with COVID-19, caution should be used prior to cuff deflation. The patient should be in an isolated room or cohorted with other patients with COVID-19 prior to cuff deflation.
The first time the cuff is deflated may be uncomfortable for the patient and may take time for the patient to get used to the sensation of airflow through the upper airway. Therefore, multiple attempts may be required before the patient is able to manage a fully deflated cuff.
The cuffs should be checked routinely, adjusted to the appropriate pressure, and the tube replaced if the cuff is not holding air (Mitchel et al, 2012). Cuff pressure should be checked regularly with a cuff manometer. High cuff pressure can lead to mucosal ischemia and eventual injury with complications such as tracheal stenosis, necrosis, bleeding, ulcers, and fistulas. It is recommended that cuff pressures be maintained at 20-30cmH20 (15–22 mm Hg).
Due to the complications that can occur with a cuffed tracheostomy, cuff deflation or a cuffless tracheostomy tube should be considered if the patient is weaned from mechanical ventilation and is able to tolerate a deflated cuff without respiratory distress. More information about cuff management can be found here.
If the tracheostomy tube has a pilot line and pilot balloon, this is an indicator that the patient has a cuffed tracheostomy tube. The flange of the tracheostomy tube also indicates if the tracheostomy tube has a cuff in place. For example the original Legacy Shiley tracheostomy tubes indicate CFS on the flange for cuffless and may also say "No Cuff." DCT indicates disposible cuffed tracheostomy. The newer Shiley flexible tracheostomy tubes "cuffed" written on the flange.
When the pilot balloon is inflated, this indicates that the cuff is inflated. When the pilot balloon is deflated, this indicates that the cuff is deflated. Prior to placing a speaking valve or cap, always use a syringe to remove all air from the pilot balloon to make sure that the cuff is fully deflated even if the pilot balloon appears to be deflated. This is because sometimes there is a small amount of air in the pilot balloon that may not be visually observed. If the cuff is not completely deflated, the patient may have difficulty breathing with a valve in place. A speaking valve or cap is contraindicated with foam filled cuffs.
A cuffless tracheostomy tube does not have a cuff (balloon like feature) at the end of the tube. If the patient does not require that the air from the ventilator is monitored and measured and is able to tolerate cuff deflation without respiratory distress, then a cuffless tracheostomy tube may be placed. Sometimes a adult patients on mechanical ventilation are managed with cuffless tracheostomy tubes, but it is not common. Typically patients are weaned from mechanical ventilation prior to placement of a cuffless tracheostomy tube. Pediatric and neonatal patients typically have cuffless tracheostomy tubes to prevent mucosal injury.
When a cuffless tracheostomy tube is placed, the flow of air is different then with a tracheostomy tube with an inflated cuff. With a cuffless tracheostomy tube air will flow in and out of the tracheostomy tube, however, air may also leak around the tracheostomy tube and through the upper airway. Some speech is possible with a cuffless tracheostomy tube depending on how much space is around the tracheostomy tube for airflow through the upper airway.
A cuffless tracheostomy tube does not have a pilot line or pilot balloon. The flange of the tracheostomy tube will indicate that the tracheostomy tube is cuffless.
Patients sometimes breathe easier when a tracheostomy tube is changed to a cuffless tracheostomy tube during speaking valve trials. As mentioned above, particularly with the high volume, low pressure cuffs, the bulk of the cuff occupies space even when deflated.
It is important to understand the difference between a cuffed and cuffless tracheostomy tube and when it is appropriate to deflate the cuff or change to a cuffless tracheostomy tube. Once the patient no longer requires mechanical ventilation and is able to tolerate cuff deflation without distress, a cuffless tracheostomy tube may be placed. Since cuff deflation can increase aerosol generation, care must be taken prior to this procedure. Staff must ensure appropriate PPE and it should be performed in isolation or with cohorted COVID-19 patients.
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